Journal of Insect Science

Food preferences of the rubber plantation litter beetle, Luprops tristis, a nuisance pest in rubber tree plantations

Thomas K. Sabu and K.V. Vinod

Massive invasion of the litter dwelling beetle, Luprops tristis Fabricius (Coleoptera: Tenebrionidae), numbering about 0.5 to 4 million per residential building following summer showers, and their prolonged stay in a state of dormancy, make them the an extreme nuisance in rubber tree plantation belts of the Western Ghats in south India. Food preference of post-dormancy adults, larvae and teneral adults stages towards tender, mature and senescent leaves were assessed in three choice and no choice leaf disc tests. All stages have strong preference towards fallen tender leaves and lowest preference towards senescent leaves indicating that leaf age is a major attribute determining food selection and food preference of L. tristis. Ready availability of the preferred, prematurely fallen, tender rubber tree leaves as a food resource is suggested as being responsible for the exceptionally high abundance of L. tristis in rubber tree plantation belts.

Comparison of similarity coefficients used for cluster analysis with amplified fragment length polymorphism markers in the silkworm, Bombyx mori

Establishing accurate genetic similarity and dissimilarity between individuals is an essential and decisive point for clustering and analyzing inter and intra population diversity because different similarity and dissimilarity indices may yield contradictory outcomes. We assessed the variations caused by three commonly used similarity coefficients including Jaccard, Sorensen-Dice and Simple matching in the clustering and ordination of seven Iranian native silkworm, Bombyx mori L. (Lepidoptera: Bombycidae), strains analyzed by amplified fragment length polymorphism markers. Comparisons among the similarity coefficients were made using the Spearman correlation analysis, dendrogram evaluation (visual inspection and consensus fork index - CI_C), projection efficiency in a two-dimensional space, and groups formed by the Tocher optimization procedure. The results demonstrated that for almost all methodologies, the Jaccard and Sorensen-Dice coefficients revealed extremely close results, because both of them exclude negative co-occurrences. Due to the fact that there is no guarantee that the DNA regions with negative co-occurrences between two strains are indeed identical, the use of coefficients such as Jaccard and Sorensen-Dice that do not include negative co-occurrences was imperative for closely related organisms.

Digestive proteolytic activity in the Sunn pest, Eurygaster integriceps

Vahid Hosseininaveh, Alireza Bandani, and Fatemeh Hosseininaveh

The Sunn pest, Eurygaster integriceps Puton (Heteroptera: Scutelleridae), is one of the most important pests of wheat and causes considerable damage to this valuable crop annually. Digestive proteinase activity of adult insects was investigated using general and specific substrates and inhibitors. Proteolytic activity was low when the common conventional substrates, azoalbumin, azocasein and hemoglobin were used to assay salivary glands and midguts. Using the fluorescent casein substrate (BODIPY FL casein), total proteolytic activity was measured at different pH. Maximum proteolytic activity was detected at pH 7 (100%) and 8(65 %) which suggested the presence of serine proteinases in the salivary glands. There was no detectable proteolytic activity in midgut extracts. The inhibitors; PMSF (inhibitor of serine proteinases) and TPCK (a specific chymotrypsin inhibitor) showed greater than 50% inhibitory effect on total proteolytic activity, however, TLCK (specific trypsin inhibitor) and E-64(specific cysteine proteinase inhibitor) did not inhibit total proteolytic activity. Using fluorescent specific substrates for serine and cysteine proteinases (Z-Arg-AMC, Z-Arg-Arg-AMC, Z-Arg-Phe-AMC and Suc-Ala-Ala-Pro-Phe-AMZ) revealed the presence of tryptic and chymotryptic activity in the salivary gland extract. Zymogram analysis under non-reducing SDS-PAGE conditions and using the substrate APNE showed at least 8 tryptic and chymotryptic activity bands in salivary gland extracts. A single high molecular weight band with tryptic activity (165 kDa) was detected using the substrate BApNA in a zymogram analysis uisng native-PAGE. Kinetic studies showed a k_m value of 0.6 mM for this enzyme against the substrate BApNA .The inhibitor TLCK decreased activity of the trypsin-like enzyme up to 73% and almost completely eliminated the only band related to this proteinase in the zymogram. Soybean Kunitz type trypsin inhibitor showed no effect on proteolytic activity of the trypsin-like serine proteinase. In general, the results revealed the presence of chymotrypsin- and trypsin-like serine proteinases in the salivary gland of E. integriceps, and it seems that the major total proteolytic activity is due to chymotrypsin proteinases.

Genetic differentiation between resistance phenotypes in the phytophagous flea beetle, Phyllotreta nemorum

The flea beetle Phyllotreta nemorum L. (Coleoptera: Chrysomelidae) is genetically polymorphic for resistance against the defences of one of its host plants, Barbarea vulgaris R.Br. (Brassicales: Brassicaceae). Whereas resistant flea beetles are able to use B. vulgaris as well as other cruciferous plants as food, non-resistant beetles cannot survive on B. vulgaris. This limitation to host plant use of non-resistant beetles could potentially lead to asymmetric gene flow and some degree of genetic isolation between the different resistance-genotypes. Therefore, we studied the extent of genetic differentiation at neutral allozyme loci between samples of flea beetles that were collected at different locations and first tested for resistance phenotype. Since earlier work has shown a weak, but significant, effect of geographical distance between the samples on their genetic differentiation, in the present study variation at the neutral allozyme loci in P. nemorum was partitioned between geographical distance and resistance-phenotype. Both sources independently contributed statistically significantly to population differentiation. Thus, there appears to be a limitation to genetic exchange between the resistant and non-resistant flea beetles when corrections are made for their geographic differentiation. This is consistent with the presence of some degree of host race formation in this flea beetle.

High temperature effects on water loss and survival examining the hardiness of female adults of the spider beetles, Mezium affine and Gibbium aequinoctiale

Jay A. Yoder, Michael J. Chambers, Justin L. Tank, and George D. Keeney

A remarkable ability to tolerate temperatures as high as 52°C for Mezium affine Boieldieu and 56°C for Gibbium aequinoctiale Boieldieu (Coleoptera: Anobiidae) was discovered as part of a water balance study that was conducted to determine whether desiccation-resistance (xerophilic water balance classification) is linked to survival at high temperature. Characteristics of the heat shock response were an intermediate, reversible level of injury, appearing as though dead; greater recovery from heat shock by G. aequinoctiale (57%) than M. affine (30%) that supplemented higher temperature survival by G. aequinoctiale; and lack of protection generated by conditioning at sublethal temperature. Heat-induced mortality is attributed to an abrupt, accelerated water loss at 50°C for M. affine and 54°C for G. aequinoctiale, not to the species (M. affine) that loses water the slowest and has the lower activation energy, E_a, as a measure of cuticular boundary effectiveness. These temperatures where water loss increases sharply are not critical transition temperatures because Arrhenius analysis causes them to be erased (uninterrupted Boltzmann function) and E_a fails to change when cuticular lipid from these beetles is removed. Our conclusion is that the temperature thresholds for survival and accelerated water loss closely match, and the key survival element in hot and dry environments contributing to wide distribution of G. aequinoctiale and M. affine derives from rising temperature prompting entry into quiescence and a resistance in cuticular lipid fluidity.

Olfactory perception of oviposition-deterring fatty acids and their methyl esters by the Asian corn borer, Ostrinia furnacalis

Guo Lei and Guo Qing Li

Olfactory perception of myristic, palmitic, stearic and oleic acids and their corresponding methyl esters by Asian corn borer moths, Ostrinia furnacalis (Guenée) (Lepidoptera: Crambidae) were investigated. It was found that mated females with both antennae amputated, in contrast to intact females and females with one antenna removed, could not discriminate between simultaneously provided control filter papers and filters treated with a blend of oviposition-deterring fatty acids. Oviposition by mated females exhibited a very marked periodicity, with all egg masses deposited during the scotophase and most egg masses laid before midnight. According to the peak and trough period of oviposition, electroantennogram (EAG) responses from both mated females and males to the four fatty acids and four methyl esters were tested within two two-hour periods from 3 to 5 hours after the start of darkness and from 1 to 3 hours after light onset, respectively. Significant EAG responses above solvent and background were elicited by all test chemicals from females, and by most of the test compounds from males. EAG values of all test chemicals from mated females were not statistically different between the two test periods except for methyl myristate. Conversely, EAG responses from mated males to myristic acid, stearic acid and their methyl esters significantly differed between the two test periods.

Longevity and developmental stability in the dung fly Sepsis cynipsea, as affected by the ectoparasitic mite, Pediculoides mesembrinae

Oliver Y. Martin and David J. Hosken

Fluctuating asymmetry (FA) is a widely employed measure of developmental stability. It has been found to increase with many stressors including parasite infection. Associations between parasites and FA may exist for several reasons in addition to parasites being the direct cause of increased FA. Developmentally stable individuals may have superior immune systems, and be less susceptible to parasite infection, and/or may be less exposed to parasites than developmentally unstable ones. Mites negatively impact host fitness in a number of insects, and if FA is a reflection of general genetic quality, as has been proposed, associations between mite number and FA are predicted. Potential relationships were investigated between an ectoparasitic mite, Pediculoides mesembrinae (Canestrini) (Phthiraptera: Menoponidae) and FA in the common dung fly Sepsis cynipsea (L.) (Diptera: Sepsidae). While it was found that mite infested flies died much faster than flies without mites, indicating that mites indeed stress their hosts, counter to expectations, no associations between mites and FA were found in any analyses. Additionally, FA in mite-infected flies generally did not differ from previously published FA data from uninfected S. cynipsea. Nevertheless, parasitized males tended to be somewhat less asymmetrical than non-parasitized males, but based on our data, it does not appear that mite infestation is generally associated with developmental stability in S. cynipsea.

Evaluation of the susceptibility of the pea aphid, Acyrthosiphon pisum, to a selection of novel biorational insecticides using an artificial diet

Amin Sadeghi, Els J.M. Van Damme, and Guy Smagghe

An improved technique was developed to assay the toxicity of insecticides against aphids using an artificial diet. The susceptibility of the pea aphid Acyrthosiphon pisum (Harris) (Hemiptera: Aphidoidea) was determined for a selection of novel biorational insecticides, each representing a novel mode of action. Flonicamid, a novel systemic insecticide with selective activity as feeding blocker against sucking insects, showed high toxicity against first-instar A. pisum nymphs with an LC₅₀ of 20.4 μg/ml after 24 h, and of 0.24 μg/ml after 72 h. The toxicity was compared with another feeding blocker, pymetrozine, and the neonicotinoid, imidacloprid. In addition, four insect growth regulators were tested. The chitin synthesis inhibitor flufenoxuron, the juvenile hormone analogue pyriproxyfen, and the azadirachtin compound Neem Azal-T/S showed strong effects and reduced the aphid population by 50% after 3 days of treatment at a concentration of 7–9 μg/ml. The ecdysone agonist tested, halofenozide, was less potent. In conclusion, the improved aphid feeding apparatus can be useful as a miniature screening device for insecticides against different aphid pests. The present study demonstrated rapid and strong toxicity of flonicamid, and other biorational insecticides towards A. pisum.

Toxicity, tunneling and feeding behavior of the termite, Coptotermes vastator, in sand treated with oil of the physic nut, Jatropha curcas

Menandro N. Acda

Oil of the physic nut, Jatropha curcas L. (Malpighiales: Euphorbiaceae), was evaluated in the laboratory for its barrier and repellent activity against the Philippine milk termite Coptotermes vastator Light (Isoptera: Rhinotermitidae). The study showed that J. curcas oil had anti-feeding effect, induced reduction in tunneling activity and increased mortality in C. vastator. Behavior of termites exposed to sand treated with J. curcas oil indicated that it is toxic or repellent to C. vastator. Toxicity and repellent thresholds, were higher than those reported for other naturally occurring compounds tested against the Formosan subterranean termite.

Hygienic behavior, liquid-foraging, and trophallaxis in the leaf-cutting ants, Acromyrmex subterraneus and Acromyrmex octospinosus

Freddie-Jeanne Richard and Christine Errard

Neotropical leaf-cutting ants (tribe Attini) live in obligate symbiosis with fungus they culture for food. To protect themselves and their fungus garden from pathogens, they minimize the entry of microorganisms through mechanical and chemical means. In this study, focusing on the species Acromyrmex subterraneus and A. octospinosus, (Hymeoptera: Formicidae). Self- and allo-grooming behavior were quantified and it was found that A. octospinosus workers spend less time in self-grooming than A. subterraneus. In the experimental absence of fungus in A. subterraneus, the times spent in these two behaviors are not affected; however workers spend significantly more time immobile. Hygienic and trophallaxis behaviors were examined as well as the possibility that workers exchange food, and the grooming behavior of foraging and non-foraging workers were compared. Behavioral observations revealed that large workers spent more time grooming than small workers, and more than 62% of replete foragers passed collected liquid food via trophallaxis to a nestmate. However, trophallaxis was rarely observed between non-forager workers. These results suggest that trophallaxis permits the exchange of alimentary liquid between colony members, but it is not important for spreading the colony odor signature.

Spitting performance parameters and their biomechanical implications in the spitting spider, Scytodes thoracica

Robert B. Suter and Gail E. Stratton

Spitting spiders Scytodes spp. subdue prey by entangling them at a distance with a mixture of silk, glue, and venom. Using high-speed videography and differential interference contrast microscopy, the performance parameters involved in spit ejection by Scytodes thoracica (Araneae, Scytodidae) were measured. These will ultimately need to be explained in biomechanical and fluid dynamic terms. It was found that the ejection of “spit” from the opening of the venom duct (near the proximal end of the fang) was orderly. It resulted in a pattern that scanned along a lateral-medial axis (due to fang oscillations) while traversing from ventral to dorsal (due to cheliceral elevation). Each lateral-to-medial sweep of a fang produced silk-borne beads of glue that were not present during each subsequent medial-to-lateral sweep. The ejection of “spit” was very rapid. A full scan (5–57 fang cycles, one upsweep of a chelicera) typically occupied less than 30 ms and involved fang oscillations at 278–1781 Hz. Ejection velocities were measured as high as 28.8 m/s. The “spit” was contractile. During the 0.2 s following ejection, silk shortened by 40–60% and the product of a full scan by both of the chelicerae could exert an aggregate contractile force of 0.1 – 0.3 mN. Based on these parameters, hypotheses are described concerning the biomechanical and fluid dynamic processes that could enable this kind of material ejection.

Distributional patterns of Pseudacteon associated with the Solenopsis saevissima complex in South America

Classical biological control efforts against imported fire ants have largely involved the use of Pseudacteon parasitoids. To facilitate further exploration for species and population biotypes a database of collection records for Pseudacteon species was organized, including those from the literature and other sources. These data were then used to map the geographical ranges of species associated with the imported fire ants in their native range in South America. In addition, we found geographical range metrics for all species in the genus and related these metrics to latitude and host use. Approximately equal numbers of Pseudacteon species were found in temperate and tropical regions, though the majority of taxa found only in temperate areas were found in the Northern Hemisphere. No significant differences in sizes of geographical ranges were found between Pseudacteon associated with the different host complexes of fire ants despite the much larger and systemic collection effort associated with the S. saevissima host group. The geographical range of the flies was loosely associated with both the number of hosts and the geographical range of their hosts. Pseudacteon with the most extensive ranges had either multiple hosts or hosts with broad distributions. Mean species richnesses of Pseudacteon in locality species assemblages associated with S. saevissima complex ants was 2.8 species, but intensively sampled locations were usually much higher. Possible factors are discussed related to variation in the size of geographical range, and areas in southern South America are outlined that are likely to have been under-explored for Pseudacteon associated with imported fire ants.

Soybean flour and wheat germ proportions in artificial diet and their effect on the growth rates of the tobacco budworm, Heliothis virescens

Soybean flour and wheat germ are the two most important protein components of wheat germ-based insect artificial diets. The effect of modifying the proportion of these two ingredients in a Noctuidae-specific diet was investigated utilizing the tobacco budworm Heliothis virescens (F.) (Lepidoptera: Noctuidae), with the goal of developing a suboptimal diet that, without drastically affecting this insect’s growth and reproductive rates, could manifest subtle negative effects in this insect. The original diet formula contained 2.51% protein. When the proportions of soybean flour and wheat germ were changed to 2.15% protein the net reproductive rate of the first generation was significantly lower. In the second generation, the net reproductive rate, development time, percent female survivorship, fertility, intrinsic rate of increase, finite rate of increase and female longevity were significantly lower in both the 2.15% and 2.26% protein diets. The survival rate of immatures to the adult stage was 1% in the 2.05% protein diet in the first generation. Interestingly, females exposed to these suboptimal diets produced a significantly higher number of eggs but the survival of their larvae was significantly reduced. It is evident from these results that modifications to the protein content and the nutrient composition profile of the original wheat germ-based insect artificial formula can be used to produce subtle negative effects on the growth of tobacco budworm.

Preliminary results on evaluation of chickpea, Cicer arietinum, genotypes for resistance to the pulse beetle, Callosobruchus maculatus

F. Erler, F. Ö. Ceylan, T. Erdemir, and C. Toker

The chickpea, Cicer arietinum L. (Fabales: Fabaceae), seeds are vulnerable, both in the field and in storage, to attack by seed-beetles. Beetles of the genus Callosobruchus are major storage pests of chickpea crops and cause considerable economic losses. In the present study, a total of 11 chickpea genotypes including five ‘kabuli’ (Mexican white, Diyar, CA 2969, ILC 8617 and ACC 245) and six ‘desi’ chickpeas (ICC 1069, ICC 12422, ICC 14336, ICC 4957, ICC 4969 and ICC 7509) were evaluated for resistance to the pulse beetle Callosobruchus maculatus F (Coleoptera: Bruchidae). Resistance was evaluated by measuring percent damage to seeds. Damage to seeds by C. maculates was manifested by the round exit holes with the ‘flap’ of seed coat made by emerging adults. Of the 11 genotypes tested, only one (ICC 4969) exhibited a complete resistance to C. maculatusin both free-choice and no-choice tests; no seed damage was found over the test period. In general, the ‘desi’ chickpeas were more resistant to C. maculates than the ‘kabuli’ chickpeas. Among the tested chickpea genotypes, only ICC 4969 can be used as a source of C. maculates resistance in breeding programmes that could then be grown in organic cultivation free from pesticides.

Physiological activity of neuropeptide F on the hindgut of the blood-feeding hemipteran, Rhodnius prolixus

Ronald Gonzalez and Ian Orchard

Current hypotheses propose that, in the invertebrates, neuropeptide F (NPF), the vertebrate NPY homologue, may be capable of regulating responses to diverse cues related to nutritional status and feeding. An investigation into the effects of Drosophila melanogaster NPF (DrmNPF) and Anopheles gambiae NPF (AngNPF) on hindgut physiology of Rhodnius prolixus Stal (Heimptera: Reduviidae) suggests a myoinhibitory role for these peptides and the R. prolixus native peptide. Extracts of the central nervous system of R. prolixus were processed and several HPLC-fractions revealed NPF-like activity within the nanomolar equivalent range when tested using the hindgut contraction assay. Although NPF has been shown to decrease epithelial membrane potential in Aedes aegypti larval midgut preparations, NPF does not appear to play a role in epithelial transport of potassium in the hindgut. While the function of NPF has yet to be established, NPF-like effects suggest multiple physiological roles for NPF among invertebrates.

Population dynamics of the rubber plantation litter beetle Luprops tristis, in relation to annual cycle of foliage phenology of its host, the para rubber tree, Hevea brasiliensis

Thomas K. Sabu and K.V. Vinod

The population dynamics of the rubber plantation litter beetle, Luprops tristis Fabricius 1801 (Coleoptera: Tenebrionidae) was assessed in relation to the phenology of leaf shedding and defoliation pattern of para rubber trees, Hevea brasiliensis Müll. Arg (Malpighiales: Euphorbiaceae), during a two year study period. The abundance of adults, larvae and pupae per 1m2 of litter sample was recorded. Post dormancy beetles appeared in leaf litter following annual leaf shedding, whereas larvae, pupae and teneral adults were present after leaf flush. No stages were recorded from plantations following the summer rains until the annual litter fall in the next season. Parental adults peaked at the time of leaf sprouting and tender leaf fall. Larvae and teneral adults peaked at the time of premature fall of green leaves and flowers. Teneral adults of six age classes were recorded and all entered dormancy irrespective of the feeding time available to each age class. Females outnumbered males in the parent generation, while the sex ratio of new generation adults was not biased towards either sex. The phenological stages of rubber trees included leaf fall in late December and early January, leaf sprouting and new leaf production in January and flowering in February. All feeding stages of L. tristis peak in abundance when premature leaves are most abundant in the leaf litter. Prediction of the timing of appearance of various developmental stages of L. tristis in plantations, invasion into buildings and intensity of population build up in rubber belts is possible by tracking the phenology of leaf fall in rubber plantations, time of return of post dormancy adults and the onset of summer rainfall. Perfect synchrony was recorded between the field return of parental adults with annual leaf shedding, the oviposition phase of parental adults with tender leaf fall at the time of leaf sprouting, and larval and teneral adult stages with premature fall of leaves. Premature leaf availability is suggested as contributing to the reproductive efficiency of parental adults, the survival of early developmental stages and of new generation adults during dormancy.

Growth and differentiation of the larval mosquito midgut

Kathryn Ray, Maria Mercedes, Doris Chan, Chi Yan Choi, and James T. Nishiura

Factors affecting larval growth and nutrition have consequences on adult fecundity. Since the mosquito larval midgut is the primary organ of digestion and nutrient absorption, factors that affect the growth and development of the midgut may have potential consequences on the reproductive potential of the adult. To gain a better understanding of mosquito midgut development the growth and metamorphic remodeling of the Aedes aegypti L. and Culex pipiens L. (Diptera: Culicidae) midguts were investigated. Cytological evidence was obtained suggesting that, in both the anterior and posterior Ae. aegypti larval midgut, diploid regenerative cells give rise to new endoreplicating cells that significantly contribute to the growth and metabolism of the midgut. This hypothesis was supported by BrdU incorporation studies showing that diploid cells, as well as large and small endoreplicating cells, synthesize DNA during the 2nd, 3rd and 4th instars. Cytological studies of the Cx. pipiens larval midgut suggest that anterior midgut growth in this species is primarily by cell enlargement. To study metamorphic remodeling of the midgut, DNA synthesis in Ae. aegypti 4th instar midguts was followed by using 5-bromo-2-deoxyuridine (BrdU) incorporation. During the 24 hr period after the last larval-larval molt both endoreplicating and diploid cells incorporate BrdU. After the critical weight is achieved, endoreplicating cell BrdU incorporation gradually ceases while diploid cells continue to replicate. The period of maximum diploid cell incorporation correlated with the period of maximum ecdysone titer.

Daily activity patterns of two co-occurring tropical satyrine butterflies

Paulo Enrique Cardoso Peixoto and Woodruff W. Benson

Adult males and females of many insect species are expected to adjust their daily activity pattern in order to avoid stressful climatic conditions and increase the chances to encounter sexual partners. Using scan sampling methods associated with focal individual observations it was found that two satyrine butterflies of similar size and morphology, Hermeuptychia hermes (Fabricius) (Leptidoptera: Nymphalidae) and Paryphthimoides phronius (Godart), show completely different daily activity patterns on forest edges in southeastern Brazil. Hermeuptychia hermes presents one abundance peak in the morning and another in the late afternoon, while P. phronius abundance peaks in the mid-day, remaining stable until 1700 h. This difference is probably due to the occurrence of territorial behavior in the later species. The beginning of territorial defense by P. phronius males coincided with the time of new-born female activity. However, newly hatched females were not sexually receptive. The afternoon territoriality in male P. phronius may be in part related to mate acquisition. However, why the abundance of H. hermes decreases when the abundance of P. phronius increases is less clear.

Pathogenicity of the fungus, Aspergillus clavatus, isolated from the locust, Oedaleus senegalensis, against larvae of the mosquitoes Aedes aegypti, Anopheles gambiae and Culex quinquefasciatus

Fawrou Seye, Oumar Faye, Mady Ndiaye, Ebrima Njie, and José Marie Afoutou

The use of insect pathogenic fungi is a promising alternative to chemical control against mosquitoes. Among the Hyphomycetes isolated from insects for mosquito control, the genus Aspergillus remains the least studied. In September 2005, four fungi were isolated from the Senegalese locust, Oedaleus senegalensis Kraus (Orthoptera: Acrididae), collected in Dakar, Senegal. One of these fungi, identified as Aspergillus clavatus, Desmazières (Eurotiales: Trichocomacaea) was highly pathogenic against larvae of the mosquitoes Aedes aegypti L., Anopheles gambiae s.l. Giles and Culex quinquefasciatus Say (Diptera: Culicidae). An application of 1.2 mg/ml dry conidia yielded 100% mortality after 24 hours against both Ae. aegypti and Cx. quinquefasciatus while with An. gambiae it was 95%. With unidentified species in the genus Aspergillus, mortality after 24 h was <5% against all the larval species. Application of A. clavatus produced in a wheat powder medium using doses ranging between 4.3 to 21x107 spores/ml, caused 11 to 68% mortality against Cx. quinquefasciatus at 24h, and 37 to 100% against Ae. aegypti. Microscopic observations showed fungal germination on both Ae. aegypti and Cx. quinquefasciatus larvae. Histological studies revealed that A. clavatus penetrated the cuticle, invaded the gut and disintegrated its cells. Some Cx. quinquefasciatus larvae, treated with A. clavatus reached the pupal stage and produced infected adults. However, the infection was mainly located on the extremity of their abdomen. These results suggest that A. clavatus could be an effective tool to manage mosquito proliferation.

Response of the cutworm Spodoptera litura to sesame leaves or crude extracts in diet

Henry Ofosuhene Sintim, Toru Tashiro, and Naoki Motoyama

The effects of extracts of sesame, Sesamum indicum L. (Liamiales: Pedaliaceae), and whole leaves of some selected cultivars of sesame were tested using a natural host Spodoptera litura (F.) (Lepidoptera: Noctuidae). Indices taken using the immature stages include; diet utilization, growth and development and induction of detoxification enzymes. The results indicate that S. litura generally selects its food amongst cultivars within 6 hours after food presentation. Growth and development of the insect is controlled also by plant acceptability and quality. Although all the cultivars tested significantly limit insect growth and development the variety 56S-radiatum did not allow a complete life cycle as pupation from first instar stage was 0%. Generally the crucial period for immature S. litura was the larval period, especially the first two instars where the weight of an insect fed on an experimental diet was three times lower than that of a control diet. The larval developmental period was greater than 40 days as compared to 17 days for insects fed a control diet. S. litura also had lowered efficiency in utilizing ingested food, from a low of 13% in a sesame cultivar to 45% in the control diet. The key detoxification enzyme was a glutathione s-transferase that was confirmed by a 6-fold increase between S. litura fed a plant cultivar vs. a control diet towards the substrate 1,2-dichloro-4-nitrobenzene. First and second instars of S. litura have a relatively reduced detoxification of enzymes in response to plant cultivar diets leading to low survival. A 3% v/w crude extract of the cultivars increased enzyme induction towards all the tested substrates.

Demography and life history of the egg parasitoid, Trichogramma brassicae, on two moths Anagasta kuehniella and Plodia interpunctella in the laboratory

S Iranipour, A Farazmand, M Saber, and Jafarloo M Mashhadi

The egg parasitoid, Trichogramma brassicae Bezdenko (Hymenoptera: Trichogrammatidae) is the most important and widely distributed species of Trichogramma in Iran. It attacks eggs of several lepidopterous pests, and is a major biological control agent. Rearing parasitoids is necessary for experimental work, and, potentially, for mass release in the field. Selecting a suitable host is critical for developing a successful rearing method. If other conditions are the same, the rate of population increase will be a suitable indicator of parasitoid performance on different hosts. However, conclusions based on a single generation can be misleading because of the learning ability of parasitoids. Life history parameters of T. brassicae were studied on two hosts easily reared in the laboratory, Anagasta kuehniella Zeller, and Plodia interpunctella Hübner (Lepidoptera: Pyralidae). All the experiments were carried out at 24 ± 1°C, 65±10% RH, and 16:8 L:D photoperiod. Eight parameters including gross and net reproductive rates (GRR and R₀ respectively), intrinsic rate of natural increase (r_m), finite rate of population increase (λ), intrinsic birth and death rates (b and d respectively), cohort generation time (T), and doubling time (DT) were compared between two hosts for two generations. All parameters showed a highly significant difference (α = 0.01) between hosts. GRR, R₀, r_m, λ, and b were higher, while d, T, and DT were lower in Anagasta than Plodia. The intrinsic rate of natural increase was 0.2912 and 0.2145 female/female/day and net replacement rate was 45.51 and 19.26 female/female/generation in Anagasta and Plodia respectively. Differences between generations were significant except for r_m, λ, and d. The net replacement rate was 28.56 and 39 in the 1st and 2nd generations respectively. These results showed that A. kuehniella was a better host than P. interpunctella. Higher reproduction occurred in the second generation that may be due to increased adaptation to experimental conditions.

Egg formation in Lepidoptera

William H. Telfer

Reproductive biology in the Twentieth Century produced comprehensive descriptions of the mechanisms of egg formation in most of the major orders of insects. While many general principles of ovarian development and physiology emerged, every order turned out to have a set of its own special motifs. Discovery of the lepidopteran motifs is summarized in this essay. The emphasis is on developmental mechanisms, beginning with the early growth and differentiation of female germ cells and ending, after many turns in morphogenesis, physiology and biosynthesis, with eggs that are filled with yolk and encased in chorions. Examples of uniquely lepidopteran traits include the cellular composition of ovarian follicles, the number of tubular ovarioles in which they mature, the functions of cell-to-cell junctional complexes in their maturation, their use of glycosaminoglycans to maintain intercellular patency during vitellogenesis, the role of proton and calcium pumps in their ion physiology, a separate postvitellogenic period of water and inorganic ion uptake, and the fine structure and protein composition of their chorions. Discovery of this combination of idiosyncracies was based on advances in the general concepts and techniques of cell and molecular biology and on insights borrowed from studies on other insects. The lepidopteran ovary in turn has contributed much to the understanding of egg formation in insects generally.

Impact of darker, intermediate and lighter phenotypes of body melanization on desiccation resistance in Drosophila melanogaster

Ravi Parkash, Subhash Rajpurohit, and Seema Ramniwas

A possible link between melanization and desiccation resistance can be inferred if within population differences in melanization find significant correlations with desiccation resistance and its mechanistic basis i.e. rate of water loss/hr. Accordingly, darker, intermediate and lighter phenotypes of body melanization were analyzed in wild and laboratory reared Drosophila melanogaster L. (Diptera: Clyclorrapha) populations from highland and lowland sites located in close proximity at five different latitudinal locations (11.15 °N to 31.06°N) within the Indian subcontinent. In large population samples, occurrence of significant within population variability made it possible to assort non-overlapping phenotypes of body coloration (i.e. lighter (< 25%), intermediate (30 to 40%) and darker (> 45%)) for all the populations which were further investigated for desiccation resistance and rate of water loss/hr. Significantly, higher desiccation resistance but much reduced rate of water loss/hr were observed in darker and intermediate phenotypes in all the populations. By contrast, lighter phenotypes exhibited lower desiccation tolerance but higher rate of water loss/hr. A regression analysis between traits provided similar slope values for wild and laboratory populations. For all three physiological traits, predicted trait values from multiple regression analysis as a simultaneous function of annual average temperature and relative humidity, matched the observed values. We infer that parallel changes in melanization and desiccation resistance may result from decreasing annual average temperature and relative humidity along increasing latitude as well as altitude on the Indian subcontinent.

Distribution and abundance of parasites of the rhodesgrass mealybug, Antonina graminis: Reassessment of a classic example of biological control in the southeastern United States

Jillian M. Chantos, S. Bradleigh Vinson, and Ken R. Helms

Control of the rhodesgrass mealybug, Antonina graminis Maskell (Hemiptera: Pseudococcidae), by the encyrtid wasp Neodusmetia sangwani is considered a textbook example of classical biological control. However, recent evidence suggests that A. graminis is abundant in the southeastern United States and no recent surveys have been conducted to determine the status of N. sangwani or other A. graminis parasites. A survey was conducted and it was found that N. sangwani was uncommon overall, occurring at only 20 percent of survey sites. In addition, N. sangwani exhibited a patchy geographic distribution. Possible causes for these results are that N. sangwani has not dispersed widely since its introduction, or that the imported fire ant, Solenopsis invicta, is interfering with biological control. These results suggest that a reevaluation of the efficacy of biological control may be necessary. The survey also found two other encyrtid wasps utilizing A. graminis as a host. One, Acerophagus sp., is apparently native and was nearly as frequent as N. sangwani, while the other, Pseudectroma sp., is apparently introduced and relatively rare.

A survey of scale insects (Sternorryncha: Coccoidea) occurring on table grapes in South Africa

Vaughn M. Walton, Kerstin Krüger, Davina L. Saccaggi, and Ian M. Millar

Increasing international trade and tourism have led to an increase in the introduction of exotic pests that pose a considerable economic threat to the agro-ecosystems of importing countries. Scale insects (Sternorryncha: Coccoidea) may be contaminants of export consignments from the South African deciduous fruit industry to the European Union, Israel, United Kingdom and the United States, for example. Infestations of immature scale insects found on South African fruit destined for export have resulted in increasing rates of rejection of such consignments. To identify the risk posed by scale insect species listed as phytosanitary pests on table grapes to the abovementioned importing countries, a field survey was undertaken in 2004–2005 in vineyards throughout all grape-producing regions in South Africa. Coccoidea species found during the current field survey were Planococcus ficus (Signoret), Pseudococcus longispinus (Targioni-Tozzetti), Coccus hesperidum L. and Nipaecoccus viridis (Newstead). With the exception of Pl. ficus, which has only been collected from Vitis vinifera (Vitaceae) and Ficus carica (Moraceae) in South Africa, these species are polyphagous and have a wide host range. None of the scale insect species found to occur in vineyards in South Africa pose a phytosanitary risk to countries where fruit are exported except for Ferrisia malvastra (McDaniel) and N. viridis that have not been recorded in the USA. All scale insects previously found in vineyards in South Africa are listed and their phytosanitary status discussed. The results of the survey show that the risk of exporting scale insect pests of phytosanitary importance on table grapes from South Africa is limited.

Seasonality of litter insects and relationship with rainfall in a wet evergreen forest in south Western Ghats

Anto Anu, Thomas K Sabu, and PJ Vineesh

The seasonality of litter insect abundance and its relationship with rainfall was analyzed in a wet evergreen forest on the windward side of south Western Ghats. Monthly litter samples were collected using Berlese funnels during 4 seasons of a year: southwest monsoon season (June–August), northeast monsoon season (September–November), summer (March –May) and pre-summer season (December–February). Insect fauna as a whole showed no seasonal variation in abundance, however, some individual insect orders showed significant seasonal variation. Overall insect fauna and individual orders were distributed independently relative to rainfall. All insect orders with the exception of Psocoptera were present during all four seasons. Coleoptera (42%) was the dominant group in all seasons followed by Formicidae (12.3%), insect larvae (10.1%), Collembola (9.2%) and Thysanoptera (8.9%). Exceptionally high abundance of Ptiliidae contributed to the unprecedented abundance of litter Coleoptera. The aseasonality of litter insect fauna as a whole is attributed to year-round availability of rainfall and the absence of severe summer conditions.

Field and laboratory responses of male leaf roller moths, Choristoneura rosaceana and Pandemis pyrusana, to pheromone concentrations in an attracticide paste formulation

Tomislav Curkovic, Jay F. Brunner, and Peter J. Landolt

Male leafroller moths, Choristoneura rosaceana (Harris) (Lepidoptera: Tortricidae) and Pandemis pyrusana (Kearfott), were evaluated for responses to a paste formulation loaded with a range of concentrations of the two species’ pheromone blends and evaluated in a laboratory wind tunnel and in the field. Response criteria were flight, flight towards the pheromone source, and contact with the pheromone source for the wind tunnel assays, and capture of moths in traps for the field tests. In the wind tunnel and field, responses of males of both species to the paste generally increased as the pheromone concentration in the paste was increased. There was little response by either species to paste with less than 0.16% pheromone. The relationship between pheromone concentration and response for P. pyrusana was linear and for C. rosaceana was sinusoidal over the range of pheromone concentrations tested. These patterns were seen both in the wind tunnel and in the field. Initial release rates from the paste of (Z)-11-tetradecenyl acetate, the main component of the pheromone blends of both species was 3.6–3.8 ng/h. Inhibitory thresholds for responses were not reached for either species, using pheromone concentrations as high as 16%, in either the wind tunnel or the field. For both species, response of males to rubber septa with one mg pheromone loads was similar to the response to the paste with pheromone at concentrations greater than 3–4%. For C. rosaceana, rates of contact with the paste in the wind tunnel were statistically similar to rates of contact in response to conspecific females, with paste pheromone concentrations above 1.6%. Response rates for males of P. pyrusana were significantly lower to the paste than to conspecific females at all paste pheromone concentrations tested. Overall, the optimum pheromone concentration in the paste for moth attraction to contact was 3.2 % for C. rosaceana and 8% for P. pyrusana.

Future fitness of female insect pests in temporally stable and unstable habitats and its impact on habitat utility as refuges for insect resistance management

Michael A. Caprio, C. D. Parker, and John C. Schneider

The long-term fitness of individuals is examined in complex and temporally dynamic ecosystems. We call this multi-generation fitness measure “future fitness”. Helicoverpa zea (Boddie) (Lepidoptera: Noctuidae) is a polyphagous insect that feeds on many wild and cultivated hosts. While four generations of H. zea occur during the cropping season in the U.S. Mid Southern agroecosysem, the latter two generations were of most interest, as corn (which has been largely non-transgenic in the Mid-South) dominates the first two generations in the cropping system. In simulations of the evolution of resistance to Bt-transgenic crops, cotton refuge areas were found to be significantly more effective than similar soybean acreages at delaying the evolution of resistance. Cotton is a suitable host for H. zea during two late summer generations, while a soybean field is suitable for only one of these generations, therefore soybean fields of other maturity groups were simulated as being attractive during the alternative generation. A hypothetical soybean variety was tested in which a single field would be attractive over both generations and it was found to be significantly more effective at delaying resistance than simulated conventional soybean varieties. Finally, the placement of individuals emerging at the start of the 3rd (first without corn) generation was simulated in either refuge cotton, conventional soybean and the hypothetical long attractive soybean and the mean number of offspring produced was measured at the end of the season. Although females in conventional and long soybean crops had the same expected fecundity, because of differences in temporal stability of the two crops, the long soybean simulations had significantly more H. zea individuals at the end of the season than the conventional soybean simulations. These simulations demonstrate that the long-term fecundity associated with an individual is dependent not only on the fecundity of that individual in its current habitat, but also the temporal stability of habitats, the ecosystem at large and the likelihood that the individual’s offspring will move into different habitats.

Digestion of starch granules from maize, potato and wheat by larvae of the the yellow mealworm, Tenebrio molitor and the Mexican bean weevil, Zabrotes subfasciatus

Scanning electron microscopy images were taken of starch granules from different sources following exposure in vivo and in vitro to gut α-amylases isolated from Tenebrio molitor L. (Coleoptera: Tenebrionidae) and Zabrotes subfasciatus Boheman (Coleoptera: Bruchidae). One α-amylase was isolated from whole larval midguts of T. molitor using non-denaturing SDS-PAGE, while two other α-amylase fractions were isolated from whole larval midguts of Z. subfasciatus using hydrophobic interaction chromatography. , Digested starch granules from larvae fed on maize, potato or wheat were isolated from midgut contents. Combinations of starch granules with isolated α-amylases from both species showed similar patterns of granule degradation. In vitro enzymatic degradation of maize starch granules by the three different α-amylase fractions began by creating small holes and crater-like areas on the surface of the granules. Over time, these holes increased in number and area resulting in extensive degradation of the granule structure. Granules from potato did not show formation of pits and craters on their surface, but presented extensive erosion in their interior. For all types of starch, as soon as the interior of the starch granule was reached, the inner layers of amylose and amylopectin were differentially hydrolyzed, resulting in a striated pattern. These data support the hypothesis that the pattern of starch degradation depends more on the granule type than on the α-amylase involved.

Scaling of individual phosphorus flux by caterpillars of the whitemarked tussock moth, Orygia leucostigma

T. D. Meehan and R. L. Lindroth

We conducted a laboratory study to evaluate the effects of body mass, environmental temperature, and food quality on phosphorus (P) efflux by caterpillars of the whitemarked tussock moth, Orygia leucostigma, J. E. Smith (Lepidoptera: Lymantriidae). We found that individual phosphorus efflux rate (Q, the rate at which excreted and unassimilated P was egested in frass, mg P/day) was related to larval mass (M, mg dry) and environmental temperature (T, K) as Q = e14.69 M1.00 e−0.54/kT, where k is Boltzmann’s constant (8.62 × 10−5 eV/K, 1 eV = 1.60 × 10−19 J). We also found that P efflux was not related to food phosphorous concentration, and suggest that this result was due to compensatory feeding by larvae eating low quality leaves. The P efflux model resulting from this analysis was simple and powerful. Thus, it appears that this type of model can be used to scale P flux from individual larvae to the population level and link species of insect herbivores to ecosystem processes.

Detection of predation using qPCR: Effect of prey quantity, elapsed time, chaser diet, and sample preservation on detectable quantity of prey DNA

Donald C. Weber and Jonathan G. Lundgren

Using quantitative PCR that amplified a prey-specific mtDNA 214 bp amplicon from the COI mitochondrial gene of the Colorado potato beetle, Leptinotarsa decemlineata (Say) (Coleoptera: Chrysomelidae), prey eggs of known age and number were fed to larvae of the generalist predator lady beetle Coleomegilla maculata (De Geer) (Coleoptera: Coccinellidae), to elucidate the effects of time and diet since consumption, number of prey eggs, and methods for sample fixation and preservation, on the quantity of target DNA detected . Signal was strongly attenuated directly after cessation of feeding, even when predators were immediately frozen at −20°C. However, the quantity of target detected was significantly related to the number of eggs consumed and the time elapsed time since eating. Decrease in detected prey DNA was consistent with a negative exponential model. The target DNA sequence disappeared from starved predators (quantitative half-life estimate of 59 min) more slowly than those fed potato aphids after consuming the target prey eggs (half-life estimate 16 min), whereas those fed C. maculata eggs as a chaser were intermediate in the rate at which they degraded the target prey DNA sequence. Fixative protocols are of critical importance in proper use of the qPCR technique. Among seven methods tested, storing the predator immediately in 70% ethanol prechilled to 20°C yielded the highest amount of target sequence, 22.8% of that recovered directly from a single intact prey egg. Samples frozen without solvent at −80°C and −20°C yielded only 6.0% and 2.3% of the target DNA respectively, and room temperature ethanol and ethylene glycol-based antifreeze averaged below 1% recovery of target DNA. Nevertheless, target prey was detected in more than 80% of antifreeze-stored predators. Predators killed and held at room temperature for 4 h or 5 days yielded no target prey DNA in 18 of 20 cases. These results emphasize both the value and the complexities of application of the qPCR technique to field predation studies.

Economic injury level of the psyllid, Agonoscena pistaciae, on pistachio, Pistacia vera cv. Ohadi

The pistachio psylla, Agonoscena pistaciae Burckhardt and Lauterer (Hemiptera: Psyllidae) is a major pest of pistachio trees, Pistacia vera L. (Sapindalis: Anacardiaceae) throughout pistachio-producing regions in Iran. Different density levels of A. pistaciae nymphs were maintained on pistachio trees by different insecticide dosages to evaluate the relationship between nymph density and yield loss (weight of 1000 nuts). Psylla nymph densities were monitored weekly by counting nymphs on pistachio terminal leaflets. There was a significant reduction in weight of 1000 nuts as seasonal averages of nymphs increased. Regression analysis was used to determine the relationship between nymph density and weight of 1000 nuts. The economic injury levels varied as a function of market values, management costs, insecticide efficiency and yield loss rate and ranged from 7.7 to 30.7 nymphal days per terminal leaflet, based on weight of 1000 nuts.

Species richness and host associations of Lepidoptera-attacking Tachinidae in the northeast Ecuadorian Andes

John O. Stireman, Harold F. Greeney, and Lee A. Dyer

Most of the unknown biological diversity of macro-organisms remaining to be discovered and described lies in the tropical regions of the world and consists primarily of insects. Those insects with parasitoid lifestyles constitute a significant portion of insect diversity, yet parasitoids are among the most poorly known of major insect guilds in the humid tropics. Here we describe and analyze the richness of one diverse taxon of parasitoids, flies in the family Tachinidae, reared from Lepidoptera as part of a biological survey of Lepidoptera and their parasitoids in one mid-elevation (2000 m) area in the northeast Ecuadorian Andes. One hundred fifty-seven separable tachinid “morpho-species” were reared from approximately 160 species of Lepidoptera in 16 families. These tachinid flies were recovered from a sample of over 12,800 “successful” caterpillar rearing events that resulted in either adult Lepidoptera or parasitoids. Tachinid species accumulation and rarefaction curves exhibit no sign of reaching an asymptote and richness estimators indicate that the community likely consists of nearly twice this number of species (at minimum). Most tachinid species were reared infrequently, with 50% being represented by a single individual. The majority of species appeared to be relatively specialized on one or a few related hosts, but sampling was insufficient to make strong inferences regarding host range. The tribes Blondeliini and Goniini were the best represented, but some tribes that were expected to be common such as Tachinini and Winthemiini were poorly represented. The estimates of tachinid species richness derived here are suggestive of a far more diverse tachinid community than in temperate localities in North America. Additional rearing of Lepidoptera, as well as other herbivorous insect taxa, along with the use of additional collecting methods will be necessary to achieve a more accurate understanding of the richness of tropical Tachinidae and their contribution to broader patterns of tropical biodiversity.

The early stages of Pedaliodes poesia (Hewitson, 1862) in eastern Ecuador (Lepidoptera: Satyrinae: Pronophilina)

We describe the immature stages Pedaliodes poesia Hewitson, 1862 from northeastern Ecuador. Chusquea scandens (Poaceae, Bambusoidea) is the larval food plant. Eggs are laid singly or in pairs on the bottom side of host plant leaves. The duration of the egg, larval, and pupal stages, combined, is 99–107+ days.

Nine new species of Aleiodes Wesmael reared at Yanayacu Biological Station (Hymenoptera: Braconidae: Rogadinae) in eastern Ecuador

Andrew C. Townsend and Scott R. Shaw

Nine new species of Aleiodes (Braconidae: Rogadinae) are described and illustrated: A. aclydis, A. albiterminus, A. arbitrium, A. atripileatus, A. capillosus, A. greeneyi, A. nebulosus, A. speciosus and A. stilpnos. Because of the difficulties in distinguishing Neotropical species that belong to the circumscriptus and gastritor species-groups, a larger species-group combining the two, termed the circumscriptus/gastritor species-group, is created. The new species described in this study belonged to the seriatus, albitibia, gressitti, and circumscriptus/gastritor species-groups, respectively. Aleiodes capillosus represents the first Neotropical species belonging to the gressitti species-group. Of the 34 previously described Neotropical species in Aleiodes, only 13 have known biologies. The Aleiodes species in this study were reared from the families Geometridae and Noctuidae, two of the most common host families of other Aleiodes species worldwide.

A new species of Andesipolis Whitfield & Choi from the eastern Andes of Ecuador with notes on biology and classification (Hymenoptera: Braconidae: Rhysipolinae)

Andrew C. Townsend and Scott R. Shaw

A new species of braconid wasp, Andesipolis yanayacu, is described from the eastern Andes of Ecuador. Andesipolis yanayacu was reared as a gregarious koinobiont parasitoid of shelter building Pyralidae (Lepidoptera) larvae feeding on Urticaceae (Phenax rugosus and Boehmeria bullata). These are the first biological observations for the genus Andesipolis and the first species recorded from Ecuador. This is also the northern-most record for the genus as previously described species are from Chile. Based on morphological attributes and the newly discovered biology, Andesipolis is re-classified from the subfamily Mesostoinae into the subfamily Rhysipolinae.

The immature stages and natural history of Veladyris pardalis (Salvin, 1869) in eastern Ecuador (Lepidoptera: Nymphalidae: Ithomiinae)

We describe the immature stages and oviposition behavior of Veladyris pardalis (Salvin, 1869) from northeastern Ecuador. An unidentified species of Solanum (Solanaceae) is the larval food plant. Eggs are laid singly on leaves, stems or epiphytes growing on the host. Veladyris pardalis has four larval stadia, and takes 64–70 days to mature from oviposition to adult.

A new species of solitary Meteorus (Hymenoptera: Braconidae) reared from caterpillars of toxic butterflies (Lepidoptera: Nymphalidae) in Ecuador

Scott R. Shaw and Guinevere Z. Jones

A new species of parasitoid wasp, Meteorus rugonasus Shaw and Jones (Hymenoptera: Braconidae), is described from the Yanayacu Biological Station, Napo Province, Ecuador. The new species is diagnosed and compared to other species in the genus. It was reared from larvae of Pteronymia zerlina (Hewitson, 1855) (Lepidoptera: Nymphalidae, Ithomiinae) found feeding on leaves of Solanum (Solanaceae). The parasitoid is solitary. This is the first record of a Meteorus species attacking ithomiine Nymphalidae.

The immature stages and shelter building behavior of Falga jeconia ombra Evans, 1955 in eastern Ecuador (Lepidoptera: Hesperiidae: Hesperiinae)

Harold F. Greeney and Andrew D. Warren

We describe the immature stages and shelter building behavior of Falga jeconia ombra Evans, 1955 from eastern Ecuador. Chusquea scandens (Poaceae, Bambusoidea) is the larval food plant. Larvae in all stadia build shelters and forcibly eject frass with the aid of an anal comb. Later instars possess an eversible prothoracic “neck” gland. Larvae are associated with moving water.

The life history and shelter building behavior of Vettius coryna coryna Hewitson, 1866 in eastern Ecuador (Lepidoptera: Hesperiidae: Hesperiinae)

Harold F. Greeney and Andrew D. Warren

We describe all life-stages of Vettius coryna coryna Hewitson, 1866 in eastern Ecuador. The details of larval shelter structure and associated shelter building behavior are described and illustrated, as observed on two grass species (Poaceae). We provide brief observations on V. coryna adult behavior and a review of known life history information for other species of Vettius Godman, 1901.

The life history and shelter building behavior of Vettius coryna coryna Hewitson, 1866 in eastern Ecuador (Lepidoptera: Hesperiidae: Hesperiinae)

Harold F. Greeney and Andrew D. Warren

The life history and shelter building behavior of Vettius coryna coryna Hewitson, 1866 in eastern Ecuador (Lepidoptera: Hesperiidae: Hesperiinae)

Harold F. Greeney and Andrew D. Warren

Reared microgastrine wasps (Hymenoptera: Braconidae) from Yanayacu Biological Station and environs (Napo Province, Ecuador): Diversity and host specialization

James B. Whitfield, Josephine J. Rodriguez, and Paul K. Masonick

The microgastrine braconid wasps recovered up through 2007 by the NSF-sponsored rearing project “Caterpillars and Parasitoids of the Eastern Andes in Ecuador” are summarized in terms of their host specialization and faunistic uniqueness. Two hundred fifty eight rearings of caterpillars resulted in records of Microgastrinae, distributed among 14 genera (Apanteles Förster, Choeras Mason, Cotesia Cameron, Diolcogaster Ashmead, Distatrix Mason, Dolichogenidea Viereck, Exix Mason, Glyptapanteles Ashmead, Hypomicrogaster Ashmead, Papanteles Mason, Parapanteles Ashmead, Protapanteles Ashmead, Sathon Mason and Venanus Mason). Eleven records of hyperparasitoids of Microgastrinae are also summarized; Mesochorus Gravenhorst (Ichneumonidae) and Perilampidae are both recorded. The results are compared to those recovered by surveys in other parts of the world, especially by the Janzen-Hallwachs survey of the Area de Conservación Guanacaste (ACG) in Costa Rica. An annotated list of microgastrine genera not yet recorded at Yanayacu, but which we expect to eventually find there based on extrapolation from their known geographic distributions, is provided.

The early stages and natural history of Antirrhea adoptiva porphyrosticta (Watkins, 1928) in eastern Ecuador (Lepidoptera: Nymphalidae: Morphinae)

Here we describe the immature stages and ecological associations of Antirrhea adoptiva porphyrosticta Watkins, 1928 (Lepidoptera:Nymphalidae:Morphinae). The cloud forest bamboo, Chusquea scandens Kunth (Bambusoidea: Poaceae), serves as the larval food plant for this butterfly in eastern Ecuador, the first hostplant record for Antirrhea outside the family Arecaceae. The larvae of A. adoptiva porphyrosticta are superficially similar to those of other Antirrhea species. We also provide observations on adult and larval behavior. Caterpillars of this butterfly species are parasitized by tachinid flies, as well as by Ichneumonidae and a newly described braconid wasp.

The early stages and natural history of Antirrhea adoptiva porphyrosticta (Watkins, 1928) in eastern Ecuador (Lepidoptera: Nymphalidae: Morphinae)

A key to New World Distatrix Mason (Hymenoptera: Braconidae), with descriptions of six new reared Neotropical species

Six new species of the genus Distatrix Mason from Central and South America, D. loretta, D. xanadon, D. vigilis, D. pitillaensis, D. pandora Grinter, n. sp., and D. antirrheae Whitfield & Grinter, n. sp., are described from large-scale caterpillar inventory endeavors, mostly from the larvae of geometrid moths. Biological information and diagnostic features that distinguish these species from other previously described Distatrix, especially those from the Neotropical region, are provided; and the first key to New World species is presented. The new discoveries expand our knowledge of the World’s widespread Distatrix fauna by about a third, suggesting that similar survey efforts in other poorly sampled regions will reveal numerous additional undescribed species.

Geographic variation in host-specificity and parasitoid pressure of an herbivore (Geometridae) associated with the tropical genus Piper (Piperaceae)

The extraordinary diversity of tropical herbivores may be linked to hostplant specialization driven in part by variation in pressure from natural enemies. We quantified levels of host-specificity and parasitoid attack for the specialist herbivore, Eois (Geometridae). The goals of this research were to examine: 1) whether Eois are specialized on the genus Piper (Piperaceae) and if hostplant specialization varies geographically; 2) whether Eois are equally vulnerable to parasitoid attack across different geographic regions and by the same parasitoid families; and 3) whether parasitism levels vary with precipitation and elevation. Based on over 15,000 rearings, we found Eois caterpillars feeding exclusively on Piper. However, we did not detect geographic differences in host-specificity; each Eois species fed on an average of two Piper species. Parasitism levels of Eois varied significantly with climate and topography; Eois were most vulnerable to parasitoid attack in moist versus dry and wet forests and at low versus high elevations. The diversity of parasitoid families reared from Eois was greater in Ecuador and Costa Rica than in Panama, where parasitoids were primarily in the family Braconidae. The quantitative evidence for host-specificity provides support for the hypothesis that Eois are specialized on Piper. Our results also reveal that Eois are exposed to a mosaic of potential selective pressures due to variation in parasitoid attack over a large spatial scale.

Characterizing the cauline domatia of two newly discovered Ecuadorian ant plants in Piper: an example of convergent evolution

Eric J. Tepe, Walter A. Kelley, Genoveva Rodriguez-Castañeda, and Lee A. Dyer

The stems of some myrmecophytes in Piper are used as domatia by resident ant colonies. Hollow, ant-occupied stems were previously known only in four species of southern Central American Piper, all members of Section Macrostachys. Here we present two additional, unrelated, hollow-stemmed myrmecophytes from Ecuador: P. immutatum and P. pterocladum (members of sections Radula and Peltobryon, respectively). Although similar superficially, stem cavities of the Ecuadorian Piper species differ morphologically and developmentally from those of Central American taxa. The stem cavities of P. immutatum, and possibly P. pterocladum, are formed during stem development, and begin forming only a few millimeters behind the apical meristem. This mode of cavity formation differs markedly from myrmecophytes in section Macrostachys, where the stems remain solid unless excavated by the specialized ant partner Pheidole bicornis. The stems of P. immutatum and P. pterocladum do not produce wound-response tissue around the cavity, unlike the stems in section Macrostachys. The entrance holes in stems of P. immutatum are formed through apoptotic processes and are located at each node below the petiole, whereas those in section Macrostachys are excavated by the ants in the leaf axil. This study documents convergent evolution of ant-plant associations in Piper, and emphasizes the need for careful comparison of apparently homologous, ant-associated structures in specialized myrmecophytes.

Special Feature: Diversity of insect-plant interactions in the eastern Andes of Ecuador

James S. Miller and Lee Dyer

Host plant associations of an entomopathogenic variety of the fungus, Colletotrichum acutatum, recovered from the elongate hemolock scale, Fiorinia externa

A fungal epizootic has been detected in populations of the scale Fiorinia externa Ferris (Hemiptera: Diaspididae) in the eastern hemlock, Tsuga canadensis (L.) Carrière (Pinales: Pinaceae), of several northeastern states. Colletotrichum acutatum Simmonds var. fioriniae Marcelino and Gouli var. nov. inedit (Phyllachorales: Phyllachoraceae), a well-known plant pathogen, was the most commonly recovered fungus from these infected scales. This is the second report of a Colletotrichum sp. infecting scale insects. In Brazil C. gloeosporioides f. sp. ortheziidae recovered from Orthezia praelonga is under development as a biopesticide for citrus production. C. acutatum was detected growing endophytically in 28 species of plants within the epizootic areas. DNA sequences of the High Mobility Box at the MAT1-2, mating type gene indicate that Colletotrichum sp. isolates recovered from scale insects and plants within epizootic areas were identical. Results from plant bioassays showed that this entomopathogenic Colletotrichum variety grew endophytically in all of the plants tested without causing external symptoms or signs of infection, with the exception of strawberry plants where mild symptoms of infection were observed. The implications of these findings with respect to the use of this fungus as a biological control agent are discussed.

Novel pink bollworm resistance to the Bt toxin Cry1Ac: Effects on mating, oviposition, larval development and survival

J.A. Fabrick, L. Forlow Jech, and T. J. Henneberry

Bt cotton plants are genetically engineered to produce insecticidal toxins from the Bacillus thuringiensis (Bt) bacterium Berliner (Bacillales: Bacillaceae) and target key lepidopteran pests. In all previous strains of pink bollworm, Pectinophora gossypiella (Saunders) (Lepidoptera: Gelechiidae) selected in the laboratory for resistance to insecticidal Cry1Ac toxin using an artificial diet containing the toxin, resistance to Cry1Ac and to Bt cotton is linked to three cadherin alleles (r1, r2, and r3). In contrast, the BG(4) pink bollworm strain was selected for resistance to Bt cotton by feeding larvae for four days in each of 42 generations on bolls of ‘NuCOTN33B®‘ that expressed Cry1Ac toxin. After additional selection for eleven generations on Cry1Ac-incorporated diet, the susceptibility to Cry1Ac, fecundity, egg viability, and mating of this strain (Bt4R) was compared with the unselected Cry1Ac-susceptible parent strain. Some larvae of the Bt4R strain survived on diet containing ≥10 μg Cry1Ac per milliliter artificial diet, but none survived on transgenic cotton bolls. In contrast to strains selected exclusively on Cry1Ac diet, some survival of progeny of reciprocal moth crosses of Bt4R resistant and Bt-susceptible strains occurred on Cry1Ac-treated diet, suggesting differences in levels of dominance. The Bt4R resistant strain does not have the r1, r2, or r3 mutant cadherin genes as do all previous strains of pink bollworm selected on Cry1Ac-treated artificial diet. The combined results suggest a mechanism of resistance to Cry1Ac that is different from previously described cadherin mutations.

Evaluation of yeasts and yeast products in larval and adult diets for the oriental fruit fly, Bactrocera dorsalis, and adult diets for the medfly, Ceratitis capitata, and the melon fly, Bactrocera curcurbitae

Chiou Ling Chang

Several yeasts and yeast products were tested in adult diets for the medfly Ceratitis capitata (Wiedemann), oriental fruit fly Bactrocera dorsalis (Hendel), and melon fly, Bactrocera curcurbitae (Coquillett) (Diptera: Tephritidae) and in larval liquid diet for mass-rearing B. dorsalis. Three hydrolyzed brewer’s yeasts (FNILS65, FNI200 and FNI210), one glutamine enriched yeast (GSH), one vitamin-enriched yeast (RDA500), Korea yeast, whole cell yeasts, and combinations of them were evaluated. Adult flies fed on a diet with FNI210FNI210 + GSH and RDA500 produced the highest number of eggs in all three tested fruit fly species. However, no significant difference was seen in egg hatch from flies fed on these diets with yeast in comparison to the control standard diet. When these yeasts were incorporated into a larval liquid diet with wheat germ oil, FNI200 and FNIL65 showed significantly higher pupal recovery than those from FNI210 and better adult flying and mating than those from Korea yeast. Glutamine enriched yeast enhanced fly performance, especially with FNI200 + GSH and FNILS65 + GSH, but not vitamin enriched yeast. Among the larvae reared with FNI200 + GSH, FNILS65 + GSH and torula yeast, those reared in FNILS65 + GSH diet with wheat germ oil developed the best. In order to select the most cost-effective yeast for liquid diet, FNILS65 + GSH and wheat germ oil was combined with whole cell yeast (LBI2240 series) and compared to the control diet (conventional mill feed diet currently used in the rearing facility). A ratio of 3:1 of LBI2240 and FNILS65 + wheat germ oil was selected as the most effective yeast for oriental fruit fly liquid larval diet based on cost and performance parameters.

A primer for the use of insecticidal transgenic cotton in developing countries

Many developing countries face the decision of whether to approve the testing and commercial use of insecticidal transgenic cotton and the task of developing adequate regulations for its use. In this review, we outline concepts and provide information to assist farmers, regulators and scientists in making decisions concerning this technology. We address seven critical topics: 1) molecular and breeding techniques used for the development of transgenic cotton cultivars, 2) properties of transgenic cotton cultivars and their efficacy against major insect pests, 3) agronomic performance of transgenic cotton in developing countries, 4) factors affecting transgene expression, 5) impact of gene flow between transgenic and non-transgenic cotton, 6) non-target effects of transgenic cotton, and 7) management of pest resistance to transgenic cotton.

Analysis and functional annotation of expressed sequence tags from the Asian longhorned beetle, Anoplophora glabripennis

Wayne B. Hunter, Michael T. Smith, and Laura E. Hunnicutt

The Asian longhorned beetle, Anoplophora glabripennis (Motschulsky) (Coleoptera: Cerambycidae), is one of the most economically and ecologically devastating forest insects to invade North America in recent years. Despite its substantial impact, limited effort has been expended to define the genetic and molecular make-up of this species. Considering the significant role played by late-stadia larvae in host tree decimation, a small-scale EST sequencing project was done using a cDNA library constructed from 5th-instar A. glabripennis. The resultant dataset consisted of 599 high quality ESTs that, upon assembly, yielded 381 potentially unique transcripts. Each of these transcripts was catalogued as to putative molecular function, biological process, and associated cellular component according to the Gene Ontology classification system. Using this annotated dataset, a subset of assembled sequences was identified that are putatively associated with A. glabripennis development and metamorphosis. This work will contribute to understanding of the diverse molecular mechanisms that underlie coleopteran morphogenesis and enable the future development of novel control strategies for management of this insect pest.

Natural distribution of parasitoids of larvae of the fall armyworm, Spodoptera frugiperda, in Argentina

M. Gabriela Murúa, Jaime Molina-Ochoa, and Patricio Fidalgo

To develop a better understanding of the natural distribution of the fall armyworm, Spodoptera frugiperda (Smith) (Lepidoptera: Noctuidae), and to update the knowledge of the incidence of its complex of parasitoids. S. frugiperda, samplings in whorl-stage corn were carried out in provinces of Argentina from 1999 to 2003. S. frugiperda larvae were collected from corn in localities of the provinces of Tucumán, Salta, Jujuy, Santiago del Estero, La Rioja, Córdoba, San Luis, Chaco and Misiones. In each locality 30 corn plants were sampled and only larvae located in those plants were collected. The parasitoids that emerged from S. frugiperda larvae were identified and counted. The abundance of the parasitoids and the parasitism rate were estimated. The S. frugiperda parasitoids collected were Campoletis grioti (Blanchard) (Hymenoptera: Ichneumonidae), Chelonus insularis (Cresson) (Hymenoptera: Braconidae), Archytas marmoratus (Townsend) (Diptera Tachinidae) and/or A. incertus (Macquart), Ophion sp. (Hymenoptera: Ichneumonidae), Euplectrus platyhypenae Howard (Hymenoptera: Eulophidae), and Incamyia chilensis (Aldrich) (Diptera Tachinidae). C. grioti was the most abundant and frequent during the five-year survey. Similar diversity of parasitoids was obtained in all the provinces, with the exception of I. chilensis and E. platyhypenae that were recovered only in the province of Salta. In the Northwestern region, in Tucumán, C. grioti and species of Archytas were the most abundant and frequent parasitoids. On the contrary, in Salta and Jujuy Ch. insularis was the parasitoid most abundant and frequently recovered. The parasitism rate obtained in Tucumán, Salta and Jujuy provinces were 21.96%, 17.87% and 6.63% respectively with an average of 18.93%. These results demonstrate that hymenopteran and dipteran parasitoids of S. frugiperda occurred differentially throughout the Argentinian provinces and played an important role on the natural control of the S. frugiperda larval population.

Evolution of the gene lineage encoding the carbon dioxide receptor in insects

Hugh M. Robertson and Lauren B. Kent

A heterodimer of the insect chemoreceptors Gr21a and Gr63a has been shown to be the carbon dioxide receptor in Drosophila melanogaster (Meigen) (Diptera: Drosophilidae). Comparison of the genes encoding these two proteins across the 12 available drosophilid fly genomes allows refined definition of their N-termini. These genes are highly conserved, along with a paralog of Gr21a, in the Anopheles gambiae, Aedes aegypti, and Culex pipiens mosquitoes, as well as in the silk moth Bombyx mori and the red flour beetle Tribolium castaneum. In the latter four species we name these three proteins Gr1, Gr2, and Gr3. Intron evolution within this distinctive three gene lineage is considerable, with at least 13 inferred gains and 39 losses. Surprisingly, this entire ancient gene lineage is absent from all other available more basal insect and related arthropod genomes, specifically the honey bee, parasitoid wasp, human louse, pea aphid, waterflea, and blacklegged tick genomes. At least two of these species can detect carbon dioxide, suggesting that they evolved other means to do so.

The insect chemoreceptor superfamily in Drosophila pseudoobscura: Molecular evolution of ecologically-relevant genes over 25 million years

Hugh M. Robertson

The insect chemoreceptor superfamily, consisting of the odorant receptor (Or) and gustatory receptor (Gr) families, exhibits patterns of evolution ranging from highly conserved proteins to lineage-specific gene subfamily expansions when compared across insect suborders and orders. Here their evolution across the timespan of 25 million years is examined which yield orthologous divergences ranging from 5–50%. They also reveal the beginnings of lineage-specific gene subfamilies as multiple duplications of particular gene lineages in either or both Drosophila melanogaster and D. pseudoobscura (Frolova and Astaurov) (Diptera: Drosophilidae). Gene losses and pseudogenes are similarly evident in both lineages, and even in closer comparisons of D. melanogaster with D. yakuba, leaving these species with roughly similar numbers of chemoreceptors despite considerable gene turnover. The large range of divergences and gene duplications provide abundant raw material for studies of structure and function in this novel superfamily, which contains proteins that evolved to bind specific ligands that mediate much of the ecology and mating behavior of insects.

Molecular and functional characterization of a c-type lysozyme from the Asian corn borer, Ostrinia furnacalis

Some lepidopteran lysozymes have been reported to display activity against Gram-positive and Gram-negative bacteria, in contrast to most lysozymes that are active only against Gram-positive bacteria. OstrinLysC, a c-type lysozyme, was purified from the Asian corn borer, Ostrinia furnacalis Guenée (Lepidoptera: Pyralidae), and shows activity against Gram-positive and Gram-negative bacteria. The NH₂-terminal amino acid sequence was determined by Edman degradation and used in a homology cloning strategy. The full-length cDNA contains three exons and two introns. The expression profile of the OstrinlysC gene was examined by quantitative real-time PCR. Following injection of the larvae with bacteria, the OstrinlysC gene is strongly up-regulated in immune tissues. Transcripts were also detected in gut tissue. After feeding the larvae with bacteria, OstrinlysC transcripts increased in immune tissues. A very low level of transcript abundance was also detected in gut tissue. These results suggested that the OstrinlysC gene is involved in immune responses. The three dimensional structure of OstrinLysC was predicted. Based on comparison of the 3-D structure of OstrinLysC with that of silkworm lysozyme and chicken lysozyme, we hypothesize that the positive charge-rich surface and loop-2, which is close to the cluster of hydrophobic residues, may play important roles in the interaction with the outer membrane of Gram-negative bacterial cell walls.

Resource utilization and environmental and spatio-temporal overlap of a hilltopping Lycaenid butterfly community in the Colombian Andes

Carlos Prieto and Hans W. Dahners

Coexistence by a great number of species could reflect niche segregation at several resource axes. Differences in the use of a hilltop as mating site for a Eumaeini (Lycaenidae) community were measured to test whether niche segregation exists within this group. Specimens were collected throughout 21 samplings between July-October of 2004 and July-October of 2005. Two environmental variables and three temporal-spacial variables were analyzed utilizing null models with three randomization algorithms. Significant differences were found among the species with respect to utilization of vertical space, horizontal space, temporary distribution and environmental temperature. The species did not show significant differences with respect to light intensity. For all samplings, the niche overlap observed in the two environmental variables were higher or significantly higher than expected by chance, suggesting that niche segregation does not exist due to competition within these variables. Similar results were observed for temporal distribution. Some evidence of niche segregation was found in vertical space and horizontal space variables where some samples presented lower overlap than expected by chance. The results pointed out that community’s assemblage could be mainly shaped in two ways. The first is that species with determined habitat requirements fit into unoccupied niche spaces. The second is by niche segregation in the vertical space distribution variable.

Aqueous extracts of some medicinal plants are as toxic as Imidacloprid to the sweet potato whitefly, Bemisia tabaci

Aqueous extracts of nine plants, known to have medicinal activity, were tested for their toxicity against the sweet potato whitefly, Bemisia tabaci Genn. (Homoptera: Aleurodidae) compared to the toxicity of the insecticide, Imidacloprid. Extracts of Lepidiuim sativum L. (Brassicales: Brassicaceae) killed 71 % of early stage nymphs, which was not significantly different from mortality caused by Imidacloprid. Treatment of pupae with three plant extracts, L. sativum, Achillea biebersteinii L. (Asterales: Asteraceae), or Retama raetam (Forssk.) Webb and Berthel (Fabales: Fabaceae) prevented adult development, and treatment with R. raetam extract killed adults, at levels that were not significantly different from Imidacloprid. None of the other plants showed significant toxicity. However extracts of four plants, Pimpinella anisum L. (Apiales: Apiaceae), Galium longifolium (Sibth. and SM.) (Gentianales: Rubiaceae), R. raetam and Ballota undulata Bentham (Lamiales: Lamiaceae) had a repellent effect.

The influence of temperature on the behavior of burrowing in larvae of the blowflies, Chrysomya albiceps and Lucilia cuprina, under controlled conditions

Leonardo Gomes, Guilherme Gomes, and Claudio J. Von Zuben

Blowflies use discrete, ephemeral substrates for larval development. After exhaustion of the food supply, larvae will disperse in search of sites to burrow and pupate or will seek other sources of food in a process known as post-feeding larval dispersal. In this study, the effect of temperature was investigated as it is one of the most important aspects of the environmental variables in this process. 800 larvae of the blowflies Chrysomya albiceps (Wiedemann 1819) and Lucilia cuprina (Wiedemann 1830) (Diptera: Calliphoridae) were incubated in tubes covered with vermiculite at 15 20, 25 and 30°C. For each pupa, the body weight, sex and depth of burrowing were determined. Statistical tests were used to examine the relationship of depth of burrowing and body weight to the temperature at which burrowing occurred. Depth of burrowing was affected differently by temperature for both of the species studied; L. cuprina larvae burrowed deeper at lower and higher temperatures while C. albiceps larvae burrowed less at extreme temperatures. Additionally, temperature had a significant effect on the body weight of L. cuprina larvae as body weight decreased as temperature increased, whereas for C. albiceps, larval weight increased up to 25°C and then decreased abruptly at a higher temperatures. The maximum body weight was also differently affected in the two species; in L. cuprina, the maximal weight was at 15°C and for C. albiceps weight was maximal at 20°C.

Host plant associations of an entomopathogenic variety of the fungus, Colletotrichum acutatum, recovered from the elongate hemolock scale, Fiorinia externa

Entomopathogenic activity of a variety of the fungus, Colletotrichum acutatum, recovered from the elongate hemlock scale, Fiorinia externa

A fungal epizootic in populations of Fiorinia externa Ferris (Hemiptera: Diaspididae) infesting hemlock trees, Tsuga canadensis (L.) Carrière (Pinales: Pinaceae) in forests of the Northeastern US has been recently detected. The current known distribution of the epizootic spans 36 sites in New York, Pennsylvania, New Jersey and Connecticut. Colletotrichum acutatum Simmonds var. fioriniae Marcelino and Gouli var. nov. inedit. (Phyllachorales: Phyllachoraceae) was the most prevalent fungus recovered from infected scales. Bioassays indicated that this C. acutatum variety is highly pathogenic to F. externa. Mortality rates of >90 and >55% were obtained for F. externa crawlers and settlers, respectively. Significantly lower mortality levels, ≤ 22%, were obtained when three other species of insects were assayed. C. gleosporioides has also been shown to have pathogenic activity towards a scale insect. The data suggest that C. acutatum var. fioriniae from F. externa epizootics in the US, and the previously reported C. gloeosporioides f. sp. ortheziidae causing Orthezia praelonga epizootics in Brazil, may constitute distinct biotypes of Colletotrichum that have attained the ability to infect insects in addition to the commonly reported plant hosts.

Ground dwelling ants as surrogates for establishing conservation priorities in the Australian wet tropics

This study aims to identify a set of areas with high biodiversity value over a small spatial scale within the Australian Wet Tropics. We identified sites of high biodiversity value across an altitudinal gradient of ground dwelling ant communities using three measures of biodiversity indexes. The three measures considered were the species richness, complementarity between sites and evolutionary history. The latter measure was derived using the systematic nomenclature of the ants to infer a surrogate phylogeny. The goal of conservation assessments could then be achieved by choosing the most diverse site combinations. This approach was found to be valuable for identifying the most diverse sites combinations across an altitudinal gradient that could ensure the preservation of terrestrial ground dwelling invertebrates in the Australian Wet Tropics.

Initiation of absconding-swarm emigration in the social wasp Polybia occidentalis

Peter J. Sonnentag, and Robert L. Jeanne

When a colony of the swarm-founding social wasp Polybia occidentalis loses its nest to severe weather or predation, the adult population evacuates and temporarily clusters on nearby foliage. Most of the adults remain inactive in the cluster, while foragers bring in nectar and scout wasps search the surrounding area for a new nesting site. After several hours, the scouts stimulate the rest of the swarm to leave the cluster and follow their pheromone trail to the chosen site. How scouts communicate to their swarm-mates that a site has been chosen and how they induce the swarm to depart are unknown. Video records of six Costa Rican swarms were used to quantitatively document changes in the frequencies of social behaviors leading to swarm departure. This was accomplished by going backward through the video record and following the behavior of individuals prior to their departure. Analysis of the behavior of scouts and inactive wasps indicated an increase in the frequency with which scouts bump into inactive wasps prior to swarm departure, as well as a shift in the behavior of inactive wasps from primarily receiving bumps to bumping others before departure. Thus, bumping is propagated by recently activated individuals before they take off. These observations suggest that not only is bumping an activation stimulus that causes swarm members to depart for the new nest site, but it is contagious, leading to its amplification throughout the swarm.

Seasonal patterns of the insect community structure in urban rain pools of temperate Argentina

M. Soledad Fontanarrosa, Marta B. Collantes, and Axel O. Bachmann

Temporary aquatic environments are widespread in the world, and although there are considerable regional differences in their type and method of formation they have many physical, chemical and biological properties in common. With the aim to increase knowledge of urban temporary pool fauna, the objectives of this work were to assess the seasonal patterns of species composition, richness, and diversity of the aquatic insect community inhabiting rain pools in urban temperate Argentina, and to identify the environmental variables associated to these patterns. Four temporary pools of an urban green space in Buenos Aires City were studied throughout a 1-year period. Eleven flood cycles with very varied hydroperiods and dry periods, mainly associated with rainfall, were identified. Insect species richness in these temporary urban pools, 86 taxa were documented, was found to be within the range reported for wild temporary water bodies of other regions of the world. The present results provide evidence for the existence of a clear link between habitat and community variability. Hydroperiod and seasonality were the main environmental factors involved in structuring the insect communities of the studied water bodies. Urban pools in green spaces have the potential to act to its dwellers like corridors through the urban matrix. Taking into account these characteristics and their accessibility, urban temporary pools can be considered as promising habitats for the study of ecological processes involving the insect community.

Seasonal changes in the genetic structure of an aphid-ant mutualism as revealed using microsatellite analysis of the aphid Tuberculatus quercicola and the ant Formica yessensis

Izumi Yao, and Shin-ichi Akimoto

The present study examined whether the mutualistic relationship between the aphid Tuberculatus quercicola (Matsumura) (Homoptera: Aphididae) and the attending ant Formica yessensis Forel (Hymenoptera: Formicidae) has had any mutual effects on the microgeographical genetic population structure of both partner species. The aphids and the attending ants were collected in June, August, and October 2004 from six trees of the Daimyo oak Quercus dentata Thunberg (Fagales: Fagaceae) and were genotyped using microsatellite loci. Significant genetic differentiation was detected among T. quercicola populations on the respective trees across seasons (an average of pairwise F_ST = 0.183). Similarly, significant genetic differentiation was found among populations of F. yessensis that attended aphid colonies on the respective host trees, though the averages of pairwise F_ST were lower (an average of pairwise F_ST = 0.070). An analysis of molecular variance and two-way ANOVA detected a significantly large genetic difference between spring and summer samples in F. yessensis but not in T. quercicola, indicating that changes in genetic composition occurred in the F. yessensis colony. In spite of a drastic seasonal change in the genetic difference in F. yessensis, principle coordinate analysis showed that the relative position among the six populations was maintained from spring to summer, suggesting that the tree where honeydew was available for a long time was occupied by F. yessensis over the same period and that the honeydew sources were inherited at the level of the ant colony. It is hypothesized that the suitability of host trees for the aphid T. quercicola may have an affect on the genetic structure of the attending ant F. yessensis. Within a colony of aphids, clonal diversity decreased significantly as the season progressed. The reduction in clonal diversity may be due to an increase in identical genotypes by parthenogenesis or selective pressure from host plant deterioration.

Supplemental control of lepidopterous pests on Bt transgenic sweet corn with biologically-based spray treatments

Biologically-based spray treatments, including nucleopolyhedroviruses, neem, and spinosad, were evaluated as supplemental controls for the fall armyworm, Spodoptera frugiperda (J. E. Smith), and corn earworm, Helicoverpa zea (Boddie) (Lepidoptera: Noctuidae), on transgenic sweet corn, Zea mays (L.) (Poales: Poaceae), expressing a Cry1Ab toxin from Bacillus thuringiensis Berliner (Bacillales: Bacillaceae) (Bt). Overall, transgenic corn supported lower densities of both pests than did nontransgenic corn. Control of the fall armyworm was improved in both whorl-stage and tassel-stage corn by the use of either a nucleopolyhedrovirus or neem, but the greatest improvement was seen with spinosad. Only spinosad consistently reduced damage to ears, which was caused by both pest species. In general, efficacy of the spray materials did not differ greatly between transgenic and nontransgenic corn.

The role of antennae in removing entomopathogenic fungi from cuticle of the termite, Coptotermes formosanus

Aya Yanagawa, Fumio Yokohari, and Susumu Shimizu

Our previous research has shown that the termite, Coptotermes formosanus Shiraki (Isoptera: Rhinotermitidae), protects itself from entomopathogenic fungi by mutual grooming behavior. The termite removes and discards foreign organisms, such as fungal conidia, from the body surface of its nestmates by mutual grooming behavior. The role of the antennae in detecting the condia was examind here. Three entomopathogenic fungi were used, Beauveria brongniartii 782 (Saccardo) (Hypocreales), Paecilomyces fumosoroseus K3 (Wize) (Hyphomycetes), and Metarhizium anisopliae 455 Sorokin (Hyphomycetes). Termites with antennae removed conidia more efficiently than termites without antennae. There were differences between termites with and without antennae in selection of sites to be groomed on nestmates, in the length of grooming and in occurrence of grooming. Electroantennogram (EAG) responses were recorded from termite antennae and the waveforms were rather specific to the kinds of fungi used as odor sources. Termites were able to distinguish between the tested fungi in feeding tests. These results show that the antennae play important roles in the mutual grooming behavior of the termite.

Egg parasitoids of Proconiini (Hemiptera: Cicadellidae) in northwestern Mexico, with description of a new species of Gonatocerus (Hymenoptera: Mymaridae)

Serguei V. Triapitsyn, and Julio S. Bernal

Nine species of Mymaridae and Trichogrammatidae parasitic on eggs of Proconiini sharpshooters (Cicadellidae: Cicadellinae) were collected in northwestern Mexico in relation to neoclassical biological control efforts against glassy-winged sharpshooter, Homalodisca vitripennis (Germar) in California. Gonatocerus chula Triapitsyn and Bernal sp. n., which belongs to the ater species group of Gonatocerus Nees (Mymaridae), is described. Specimens of G. chula sp. n. were reared from eggs of the smoke-tree sharpshooter, Homalodisca liturata Ball, on jojoba [Simmondsia chinensis (Link) C. K. Schneider] leaves collected in central Sonora state, Mexico. Also given are new data on other egg parasitoids of Homalodisca spp. and Oncometopia spp. in Sinaloa and Sonora states, Mexico, including Gonatocerus atriclavus Girault, G. morrilli (Howard), and G. novifasciatus Girault, and the Trichogrammatidae Burksiella sp(p)., Ittys sp., Pseudoligosita sp., Ufens ceratus Owen, and U. principalis Owen. For the first time, a species of Ittys is recorded from eggs of Proconiini, and U. principalis from Mexico. Colonies of G. atriclavus, G. novifasciatus and Pseudoligosita sp. were successfully established in a quarantine laboratory at University of California, Riverside, on eggs of the glassy-winged sharpshooter. These three parasitoid species had never been reared under laboratory conditions. In addition, seven species of Proconiini were collected in central and northwestern Mexico: Cyrtodisca major (Signoret), Homalodisca insolita (Walker), H. liturata Ball, Oncometopia sp. cf. clarior (Walker), O. sp. cf. trilobata Melichar, O. (Similitopia) sp., and Phera centrolineata (Signoret). Oncometopia sp. cf. clarior, O. sp. cf. trilobata, and O. (Similitopia) sp. appeared to be undescribed species.

Egg parasitoids of Proconiini (Hemiptera: Cicadellidae) in northwestern Mexico, with description of a new species of Gonatocerus (Hymenoptera: Mymaridae)

Serguei V. Triapitsyn, and Julio S. Bernal

Egg parasitoids of Proconiini (Hemiptera: Cicadellidae) in northwestern Mexico, with description of a new species of Gonatocerus (Hymenoptera: Mymaridae)

Serguei V. Triapitsyn, and Julio S. Bernal

Egg parasitoids of Proconiini (Hemiptera: Cicadellidae) in northwestern Mexico, with description of a new species of Gonatocerus (Hymenoptera: Mymaridae)

Serguei V. Triapitsyn, and Julio S. Bernal

Responses of descending visually-sensitive neurons in the hawkmoth, Manduca sexta, to three-dimensional flower-like stimuli.

Jordanna D. H. Sprayberry

Hawkmoths rely on vision to track moving flowers during hovering-feeding bouts. Visually guided flight behaviors require a sensorimotor transformation, where motion information processed by the optic ganglia ultimately modifies motor axon activity. While a great deal is known about motion processing in the optic lobes of insects, there has been far less exploration into the visual information available to flight motor axons. Visual information recorded at this stage has likely arisen from multiple visual pathways, and has potentially been modified by outside sensory information. As a first step, understanding the sensorimotor transformation from transduction of moving flower signals to active flower tracking behavior requires that the visual information available to the thoracic flight control centers be assayed. This paper investigated the response of descending visually sensitive neurons in the cervical connectives of the hawkmoth, Manduca sexta L. (Lepidoptera: Sphingidae), to flower-like stimuli. Because flower structure lends itself to oscillatory (vibratory) motion, the stimuli used in these experiments were discs oscillating in each axis of motion (horizontal, vertical, and looming). Object-sensitive descending-neurons (OSDNs) respond to multiple directions of object motion and do not clearly sort into classes of directional tuning. The broad spatial distribution of directional sensitivities exhibited by OSDNs indicates that the direction of object motion may be encoded on a population scale. Although OSDNs exhibit broad frequency response curves, over the range of frequencies that M. sexta are able to track (0–2 Hz) OSDNs exhibit monotonically increasing response. Additionally, OSDNs respond to discs oscillating at frequencies as high at 6 Hz, indicating that the visual information being sent to thoracic motor control centers is not likely the limiting factor in flower tracking ability.

Purification and biochemical characterization of a specific β-glucosidase from the digestive fluid of larvae of the palm weevil, Rhynchophorus palmarum

A β-glucosidase was purified from the digestive fluid of the palm weevil Rhynchophorus palmarum L. (Coleoptera: Curculionidae) by chromatography on anion-exchange, gel filtration, and hydrophobic interaction columns. The preparation was shown to be homogeneous on polyacrylamide gels. β-glucosidase is a monomeric protein with a molecular weight of 58 kDa based on its mobility in SDS-PAGE and 60 kDa based on gel filtration. Maximal β-glucosidase activity occurred at 55°C and pH 5.0. The purified β-glucosidase was stable at 37°C and its pH stability was in the range of 5.0–6.0. The enzyme readily hydrolyzed p-nitrophenyl-β-D-glucoside, cellobiose, cellodextrins and required strictly β-gluco configuration for activity. It cleaved glucose-glucose beta-(1–4) linkages better than β-(1–2), β-(1–3) and β-(1–6) linkages. The catalytic efficiency (K_cat/K_M) values for p-nitrophenyl-β-D-glucoside and cellobiose were respectively 240.48 mM−1s−1 and 134.80 mM−1s−1. Beta-glucosidase was capable of catalysing transglucosylation reactions. The yield of glucosylation of 2-phenylethanol (20 %), catalysed by the beta-glucosidase in the presence of cellobiose as glucosyl donor, is lower than those reported previously with conventional sources of beta-glucosidases. In addition, the optimum pH is different for the hydrolysis (pH 5.0) and transglucosylation reactions (pH 6.6).

Collembola are unlikely to cause human dermatitis

CSH Lim, SL Lim, FT Chew, TC Ong, and L Deharveng

There have been several unconfirmed case reports of dermatitis caused by Collembola (springtails). We recently investigated two nurses with dermatitis suspected to be caused by Drepanura Schött (Collembola: Entomobryidae). IgE antibodies to Collembola proteins were not detected in sera from the nurses and skin tests with the Collembola extract and crushed whole Collembola were negative in both the nurses and volunteers. This study suggests that the springtail Drepanura may not cause human dermatitis and that other organisms and organic matter that are also found in the moist environment inhabited by Collembola might instead be responsible.

The seasonal natural history of the ant, Dolichoderus mariae, in northern Florida

Kristina O. Laskis, and Walter R. Tschinkel

Dolichoderus mariae Forel, (Hymenoptera: Formicidae) is an uncommon, monomorphic but locally abundant, reddish-brown ant of peculiar nesting habits, whose range includes most of the eastern USA. In north Florida the ant excavates soil under wiregrass clumps or other plants with fibrous roots to form a single, large, shallow, conical or ovoid chamber broadly open to the surface around the plant base. Colonies are highly polygyne and, during the warm season, inhabit multiple nests connected only by above ground trails, over which nests exchange workers. Although monomorphic, worker size may differ significantly between colonies. The colony cycle is dominated by strong seasonal polydomy. From one or two over-wintering nests, the colonies expanded to occupy up to 60 nests by late summer, then retract once more to one or two nests by mid-winter. The worker-to-queen ratio changed greatly during this cycle, with over two thousand workers per queen during fall and winter, dropping to a low of about 300 during midsummer. Most of these summer queens probably die during the fall. Colonies reoccupy roughly the same area year to year even though they contract down to one or two nests in winter. Observation of fights in the contact zone between colonies suggested that the colonies are territorial. The ants subsist by tending aphids and scale insects for honeydew and scavenging for dead insects within their territories.

Oviposition, development and survivorship of the sweetpotato whitefly Bemisia tabaci on soybean, Glycine max, and the garden bean, Phaseolus vulgaris

Augustine Mansaray, and Abu James Sundufu

Oviposition, development and survivorship of Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae) were evaluated on soybean and garden bean under laboratory conditions of 26.0 ± 0.5 oC, 70 – 80% RH and a photoperiod of 14:10 (L:D). B. tabaci deposited more eggs and survivorship of nymphs was significantly greater in a choice-test on soybean, Glycine max L. (Merr.) (Fabeles: Fabaceae), compared to the garden bean, Phaseolus vulgaris L. Overall developmental time from egg to adult eclosion was longer on garden bean than on soybean. Also, B. tabaci was more fecund and long-lived on soybean compared to garden bean. Demographic parameters calculated from life tables on the two bean species indicate that soybean is a better host plant for B. tabaci than garden bean.

Functional morphology of the mouthparts of the adult Mediterranean fruit fly, Ceratitis capitata

Pablo A. Coronado-Gonzalez, S. Vijaysegaran, and Alan S. Robinson

Food-based attractants incorporating an insecticide are an important component of area-wide control programmes for the Mediterranean fruit fly, Ceratitis capitata (Wiedemann) (Diptera: Tephritidae). This study was carried out to understand the feeding mechanism of adults of this species. Mouthparts of C. capitata are similar in general structure to those of another Tephritid genus, Bactrocera, and have specific structural modifications that determine what adult flies can ingest. The labellum has a series of fine tube-like structures, called pseudotracheae, on its inner surface. Each pseudotrachea leads from the outer margin of the labellum and ends at the prestomum to the oral opening. The pseudotracheae contain fine micropores about 0.5μm in size. During feeding, the oral opening is never exposed to the feeding substrate but the portions of the opposing labellar lobes proximal to the oral opening are flexed against each other and distal portions of the opposing labellar lobes are opened and pressed flat against the feeding substrate or surface. The prestomal spines at the base of each pseudotrachea interlock to form a barrier across the oral opening. Thus entry of large particles directly into the crop and gut through the oral opening is prevented by flexure of the opposing labellar lobes against each other and the interlocking prestomal spines across the oral opening. Only liquids and suspended particles less than 0.5μm in size are sucked through the micropores into the lumen of the pseudotracheae and then pass into the food canal and into the crop and gut. The pseudotracheae of adult C. capitata, particularly along the middle portion of the labellum, have prominent blade-like projections that Bactrocera do not have. These projections are probably an ancestral condition as they were not observed to use them to abrade the plant or feeding surface as has been reported for species in the Tephritid genus, Blepharoneura.

Genetic variability of the European corn borer, Ostrinia nubilalis, suggests gene flow between populations in the Midwestern United States

The European corn borer, Ostrinia nubilalis (Hübner) (Lepidoptera: Crambidae), is a widely distributed and serious economic pest to corn production in the U.S. Genetic variability of O. nubilalis was studied in 18 sub-populations in the upper Midwestern United States using amplified fragment length polymorphism. The relatively low G_ST values indicate that more variation exists within populations than between populations. High gene flow (Nm) values were indicated across the entire O. nubilalis population; the lowest degree of gene flow was in the northern samples (Nm = 1.96) and the highest degree of gene flow was in the southern samples (Nm = 2.77). The differences observed in the respective regions (north vs. south) may be explained by the voltinism patterns (univoltine vs. multivoltine, respectively) of O. nubilalis: southern multivoltine populations have opportunities for multiple matings for the duration of the year, further mix alleles. AMOVA results also indicated that most of the genetic variation was within sub-populations (≈ 81% of total variation); less variation (≈13%) was detected among populations within each of the three regions as designated for this study. However, the most striking and unexpected result was the low percentage of variation between all groups (≈6%), further supporting implications of a high degree of gene flow. These results provide support for current requirements of refugia corn planting in Bt-corn management. These results also indicate that if resistance to Bt were to evolve in O. nubilalis, quick action would be necessary to deter the rapid spread of the gene for resistance.

Army ants as research and collection tools

Adrian A. Smith, and Kevin L. Haight

Ants that fall prey to the raids of army ants commonly respond by evacuating their nests. This documented behavior has been underexploited by researchers as an efficient research tool. This study focuses on the evacuation response of the southwestern desertant Aphaenogaster cockerelli André (Hymenoptera: Formicidae) to the army ant Neivamyrmex nigrescens Cresson. It is shown that army ants can be used to collect mature colonies of ants. The applicability of this tool to ecologically meaningful areas of research is discussed.

Molecular phylogenetic relationships of flightless beetles belonging to the genus Mesechthistatus Breuning, (Coleoptera: Cerambycidae) inferred from mitochondrial COI gene sequences.

Hiroshi Nakamine, and Makio Takeda

The longicorn beetles belonging to the genus Mesechthistatus Breuning, 1950 (Coleoptera: Cerambycidae) cannot fly since their hindwings are atrophied. This slows down gene flow between local populations. Currently, it is considered that the genus contains four endemic species from the eastern Honshu Is., Japan, M. binodosus, M. furciferus, M. taniguchii and M. fujisanus, that are distributed parapatrically. Sequence analyses of the cytochrome oxidase subunit I gene suggests that lineages of mitochondrial haplotypes split approximately in the same era. However, this result is not consistent with the monophyly of morphological species. The estimated evolutionary rate of the COI gene in other insects suggests that mitochondrial haplotypes of Mesechthistatus differentiated at the end of the Pliocene epoch during the Tertiary era.

Diversity of forest litter-inhabiting ants along elevations in the Wayanad region of the Western Ghats

Thomas K. Sabu, P. J. Vineesh, and K.V. Vinod

Litter ant diversity and abundance in relation to biotic and abiotic factors were analyzed at five primary forest sites lying between 300 to 1650 meter above mean sea level in the Wayanad region of the Western Ghats in Kerala, southern India. Ant abundance and species richness peaked at mid-elevations influenced by the presence of favourable physical conditions and abundance of prey resources. Dominance of ants preferring termites and Collembola as prey at sites rich in their specific prey resources indicate the influence of local prey resource availability in determining ant distribution. Dominant species (Tapinoma sp. and Solenopsis sp.) had wider distributions, being present at all elevations. Physical factors (slope of the terrain, rainfall, moisture, humidity, temperature) and prey resource availability (insect larvae, termites, Collembola) influenced ant species abundance at a regional scale f, whereas at local scales, site specific variations in the relationship between abundance of ants and prey-predators and physical factors were recorded. The present study highlights the need to consider site-specific abiotic and biotic factors while examining the distribution patterns of litter ants along altitudinal gradients in other regions of the Western Ghats, which is a recognised hot spot of biodiversity with wide regional variation in vegetation types and faunal distribution patterns.

Distribution of neuropeptide F-like immunoreactivity in the eastern subterranean termite, Reticulitermes flavipes

Andrew B. Nuss, Brian T. Forschler, Joe W. Crim, and Mark R. Brown

The nervous system and gut of worker, soldier and alate castes of the eastern subterranean termite, Reticulitermes flavipes Kollar (Isoptera: Rhinotermitidae) were examined for immunoreactivity to an antiserum to Helicoverpa zea (Boddie) (Leipidoptera: Noctuidae) MP-I (QAARPRF-NH₂), a truncated form of neuropeptide F. More than 145 immunostained axons and cell bodies were seen in the brain and all ganglia of the ventral nerve cord. Immunoreactive axons exiting the brain projected anteriorly to the frontal ganglion and posteriorly to the corpora cardiaca and corpora allata. In the stomatogastric nervous system, immunoreactive axons were observed over the surface of the foregut, salivary glands, midgut and rectum. These axons originated in the brain and from 15–25 neurosecretory cells on the foregut. Staining patterns were consistent between castes, with the exception of immunostaining observed in the optic lobes of alates. At least 600 immunoreactive endocrine cells were evenly distributed in the midguts of all castes with higher numbers present in the worker caste. Immunostaining of cells in the nervous system and midgut was blocked by preabsorption of the antiserum with Hez MP-I but not by a peptide having only the RF-NH₂ in common. This distribution suggests NPF-like peptides coordinate feeding and digestion in all castes of this termite species.

Heat treatment of the adzuki bean borer, Ostrinia scapulalis infected with Wolbachia gives rise to sexually mosaic offspring

Hironori Sakamoto, Daisuke Kageyama, Sugihiko Hoshizaki, and Yukio Ishikawa

A maternally inherited intracellular bacterium, Wolbachia, causes reproductive alterations in its arthropod hosts. In the adzuki bean borer, Ostrinia scapulalis (Walker) (Lepidoptera: Crambidae), naturally-occurring Wolbachia selectively kills male progeny. This Wolbachia strain appears to have a feminizing effect, since antibiotic treatment of infected female moths gives rise to male progeny with sexually mosaic phenotypes. It is proposed that male-specific death occurs through the feminizing effect, and sexual mosaics are produced when this effect is incompletely exerted. Here we examined whether the treatment of infected female moths with high temperatures (34ºC, 36ºC, or 38ºC), which is likely to suppress the activity of Wolbachia, induces sexually mosaic progeny. It was found that eggs laid within 24 h after treatment of Wolbachia-infected mothers at 36ºC gave rise to seven sexual mosaics along with 54 normal females. The time lag between treatment and the appearance of mosaic progeny was much shorter with heat treatment than antibiotic treatment, suggesting that heat treatment is more useful for spotting developmental timing when Wolbachia exerts its feminizing effect on O. scapulalis embryos.

Performance of host-races of the fruit fly, Tephritis conura on a derived host plant, the cabbage thistle Cirsium oleraceum: Implications for the original host shift

Thorsten Diegisser, Jes Johannesen, and Alfred Seitz

The thistle-infesting fruit fly Tephritis conura Loew (Diptera: Tephritidae) forms host races on the melancholy thistle, Cirsium heterophyllum and (L.) Hill (Asterales: Asteraceae) and the cabbage thistle, Cirsium oleraceum (L.). Scop. Previous research indicates that the host shift occurred from C. heterophyllum to C. oleraceum. In this paper we address whether the host shift involved physiological adaptations by studying oviposition acceptance and survival of the two host races on the derived host C. oleraceum. Performance differed significantly between host races. T. conura originating from C. oleraceum produced adults in 75% of all egg-laying trials in contrast to only 6.6% in T. conura originating from C. heterophyllum. Population fitness components measured as a function of life-stage was linear decreasing for T. conura on C. oleraceum but stepwise for T. conura on C. heterophyllum. Low performance of T. conura on C. heterophyllum was determined by low plant acceptance and high mortality during the larval stage, whereas hatching (at least one larva per batch) and pupae survival were not affected.

FMRFamide-like immunoreactivity in the central nervous system and alimentary tract of the non-hematophagous blow fly, Phormia regina, and the hematophagous horse fly, Tabanus nigrovittatus

Aaron T. Haselton, Chih-Ming Yin, and John G. Stoffolano

FMRFamide-related peptides (FaRPs) are a diverse and physiologically important class of neuropepeptides in the metazoa. In insects, FaRPs function as brain-gut neuropeptides and have been immunolocalized throughout the nervous system and alimentary tract where they have been shown to affect feeding behavior. The occurrence of FMRFamide-like immunoreactivity (FLI) was examined in the central nervous system and alimentary tract of non-hematophagous blow fly, Phormia regina Meigen (Diptera: Calliphoridae), and the hematophagous horse fly, Tabanus nigrovittatus Macquart (Diptera:Tabanidae). Although the central nervous system and alimentary anatomy differ between these two dipteran species, many aspects of FLI remain similar. FLI was observed throughout the central and stomatogastric nervous systems, foregut, and midgut in both flies. In the central nervous system, cells and processes with FLI occurred in the brain, subesophageal ganglion, and ventral nerve cord. FLI was associated with neurohemal areas of the brain and ventral nerve cord. A neurohemal plexus of fibers with FLI was present on the dorsal region of the thoracic central nervous system in both species. In the gut, processes with FLI innervated the crop duct, crop and anterior midgut. Endocrine cells with FLI were present in the posterior midgut. The distribution of FLI in these two flies, in spite of their different feeding habits, further supports the role of FaRPs as important components of the brain-gut neurochemical axis in these insects and implicates FaRPs as regulators of insect feeding physiology among divergent insect taxa.

Habitat preferences of butterflies in the Bumbuna forest, Northern Sierra Leone

Abu James Sundufu, and Rashida Dumbuya

The habitat preferences of the butterfly fauna were studied in the Bumbuna Forest Reserve in northern Sierra Leone. The intact forest reserve and a secondary forest regrowth, disturbed as a result of slash-and-burn agriculture, were compared to savanna habitats. Of the 290 specimens collected, 195 butterfly species were included, of which significant proportion were Nymphalidae. Of the 147 forest species, 111 (75.5%) showed preferences for the forest habitats, while 70 (47.6%) and 34 (23.1%) preferred disturbed and savannah habitats, respectively. Numerically, a comparable proportion of savannah species were recorded in the 18 disturbed (73.9%) and 16 savannah habitats (63.2%). Accumulated species richness and diversity indices were lower in the disturbed habitats compared to the forest reserve, but lowest in the savanna habitats. However, a large proportion of forest species, especially those with either a more restricted geographic range or species for which no information on geographic distribution was available, were exclusively captured in the forest patches. The survey indicated the presence of a rich butterfly fauna, which should be systematically collected for further research and study in order to build a good taxonomic database for Sierra Leone.

Phylogenetic relationships of tribes within Harpalinae (Coleoptera: Carabidae) as inferred from 28S ribosomal DNA and the wingless gene

Karen A. Ober, and David R. Maddison

Harpalinae is a large, monophyletic subfamily of carabid ground beetles containing more than 19,000 species in approximately 40 tribes. The higher level phylogenetic relationships within harpalines were investigated based on nucleotide data from two nuclear genes, wingless and 28S rDNA. Phylogenetic analyses of combined data indicate that many harpaline tribes are monophyletic, however the reconstructed trees showed little support for deeper nodes. In addition, the results suggest that the Lebiomorph Assemblage (tribes Lebiini, Cyclosomini, Graphipterini, Perigonini, Odacanthini, Lachnophorini, Pentagonicini, Catapiesini and Calophaenini), that are united by a morphological synapomorphy, within Harpalinae is not monophyletic, and the tribe Lebiini is paraphyletic with respect to members of Cyclosomini. Two unexpected clades of tribes were supported: the Zuphiitae, comprised of Anthiini, Zuphiini, Helluonini, Dryptini, Galeritini, and Physocrotaphini; and a clade comprised of Orthogoniini, Pseudomorphini, and Graphipterini. The data presented in this study represent a dense sample of taxa to examine the molecular phylogeny of Harpalinae and provide a useful framework to examine the origin and evolution of morphological and ecological diversity in this group.

Screwworms, Cochliomyia hominivorax, reared for mass release do not carry and spread foot-and-mouth disease virus and classical swine fever virus

Experiments were done to determine if transporting live screwworms Cochliomyia hominivorax Coquerel (Diptera: Calliphoridae) for developing new strains from countries where foot-and-mouth disease and classical swine fever are endemic, to the mass rearing facilities in Mexico and Panama, may introduce these exotic diseases into these countries. Are screwworms capable of harboring and spreading foot-and-mouth disease virus (FMDV) and classical swine fever virus (CSFV) when they are grown in virus-inoculated larval rearing medium? In one experiment, screwworm larvae were reared in a FMDV-inoculated artificial medium containing either 0.1% formaldehyde or antibiotics as an antimicrobial agent. In another experiment, larvae were similarly reared in a CSFV-inoculated artificial medium containing 0.1% formaldehyde. In each experiment, samples of larvae and the rearing media were collected daily until pupation occurred. The presence of FMDV was assayed by observing cytopathic effects on cell cultures and a conventional reverse transcription-polymerase chain reaction (RT-PCR); CSFV was assayed using an avidin-biotin complex assay and a conventional RT-PCR. For media containing antibiotics, FMDV was detected in a larval sample collected on day 1 and in media samples on days 1, 2 and 3. No FMDV was detected from larval and media samples collected on all other days. For media containing formaldehyde, FMDV and CSFV were not detectable in larval or media samples collected on all sampling days. These results indicate that FMDV and CSFV cannot survive in rearing medium containing formaldehyde as an antimicrobial agent. Therefore, insects collected in endemic regions and reared using formaldehyde-containing medium for at least one generation at the collection site should be free of FMDV and CSFV and can be transported safely to a strain development/mass rearing facility.

The life cycle of the root borer, Oryctes agamemnon, under laboratory conditions

Rasmi Soltani, Ikbel Chaieb, and Med Habib Ben Hamouda

The root borer, Oryctes agamemnon Burmeister (Coleoptera: Scarabaeidae), has become a serious pest of date palm trees in southwest Tunisia. Under natural conditions, mated females lay eggs in different parts of palm tree: between the hairy roots, all along the stem at the leaf axils and at the base of cut branches. Larvae bore into targeted places of the plant and were never seen outside. Pupation takes place in the plant and emergence of the adults begins in June. Larval feeding causes extensive damage to the respiratory roots. To examine the life cycle more closely, the O. agamemnon life cycle was studied under laboratory conditions. Different larval stages were collected from infested oases in Tozeur and placed in plastic boxes with natural food that was collected from the oases. After emergence, adults were paired in opaque plastic boxes for mating with the same food substrate which also served as an oviposition site. Eggs were collected daily and isolated in new boxes. Hatched eggs were recorded. The number of larval instars was determined by measuring the width of cephalic capsules. Under laboratory conditions (23 ± 2°C and 55 ± 6% RH)embryogenesis took 14.3 ± 1.42 days and the first, second and third larval instars were 33.1 ± 2.69, 63.88 ± 6.6 and 118.3 ± 13.38 days respectively. The pupal period lasted 24.1 ± 3.02 days and the adult 65.27 ± 9.48 days. These facts indicated that O. agamemnon is univoltine.

Occurrence of treehoppers (Hemiptera: Membracidae: Smiliinae) on oaks in Delaware Water Gap National Recreation Area, 2004–2006

Matthew S. Wallace

A total of 870 treehoppers and 24 species from the tribe Smiliini (Hemiptera: Membracidae: Smiliinae) were collected from various oaks in the Delaware Water Gap National Recreation Area in 2006 using yellow sticky cards. Combining all years and collecting methods, a total of 27 species were found in the park. A majority of the specimens collected in 2006 were males of Cyrtolobus vau and Ophiderma pubescens, as in previous years. Most of the treehoppers were caught in mid to late June, comparable to 2004 and 2005. It appears that many species are segregated either temporally or by oak group; some treehopper species show preference for either the red or white oak group rather than for one species of oak. Color photographs for 27 treehopper species (many including both sexes) are included.

Potentially hygroreceptive sensilla on the anal stylus of the glassy-winged sharpshooter, Homalodisca coagulata

Natalie A. Hummel, Walter S. Leal, and Frank G. Zalom

This study begins to elucidate the cues and mechanisms by which the glassy-winged sharpshooter, Homalodisca coagulata (Say) (Hemiptera: Cicadellidae), select host plants for feeding and oviposition. The electrophysiological response of the anal styli of male and female H. coagulata to water vapor was examined using a modified electroantennography (EAG) device (stylogram). A strong electrophysiological response of the anal stylus to water vapor was found. Scanning electron microscopic examination of the anal stylus revealed the presence of long mechanosensory hairs, many small coeloconic-type sensilla, and masses of secretory granules termed brochosomes. Each coeloconic sensillum is located in a pit from which protrude finger-like projections. The pit is often blocked by masses of brochosomes and an unidentified dense material. Based on the electrophysiological response of the anal stylus to water vapor, we hypothesize that the coeloconic sensilla on the stylus may be hygroreceptors. H. coagulata are xylem feeders and may use the sensilla to assist in host selection for the purpose of feeding or oviposition based on detected plant water status. Furthermore, H. coagulata oviposit into the leaf epidermis, and may use these sensilla to evaluate moisture content to determine host suitability for both oviposition and subsequent feeding of emerged progeny. Understanding the cues and underlying mechanisms of host selection is an important consideration for predicting the movement of H. coagulata between crops and disease epidemiology.

Descriptive study of damage caused by the rhinoceros beetle, Oryctes agamemnon, and its influence on data palm oases of Rjim Maatoug, Tunisia

Rasmi Soltani, Chaieb Ikbel, and Med Habib Ben Hamouda

Oryctes agamemnon (Burmeister 1847) (Coleoptera, Scarabaeidae) was accidentally introduced in the southwestern oases of Tunisia (Tozeur) around 1980 and spread to the Rjim Maatoug region. In these areas O.agamemnon was specific to date palm trees causing severe damage that can result in potential danger due to collapse of the tree. This study was conducted from April 2004 to March 2006 in 4 sites in the region of Rjim Maatoug. Different levels of palm tree attack were determined, ovioposition sites were identified, and pest damage was described in detail to specify their relative importance and to indicate factors governing palm tree attack. Eggs were individually oviposited in the attacked parts. Dead parts of palm trees were the main target of O. agamemnon including the respiratory roots, tough, trunk bark, dry petiole and the periphery of the crown. The crown itself was not attacked. Feeding by larvae caused significant damage. The biggest danger occurred when heavy attacks of larvae invaded the respiratory roots at the level of the soil, and secondarily on the periphery of the crown, which can result in fungal diseases. Several cases of Deglet Nour date palm tree collapse were caused by this pest in Rjim Maatoug. Attacks on other parts of the tree were without danger for the palm tree. In the absence of pest management, application of a quarantine program combined with field cultivation techniques could help farmers significantly decrease attack of O. agamemnon on palm trees.

Neotype designation and redescription of Toumeyella liriodendri (Gmelin) (Hemiptera: Coccoidea: Coccidae)

Takumasa Kondo, and Douglas J. Williams

In order to clarify the taxonomic status and to preserve the stability of the species, a neotype is designated for the tuliptree scale: Coccus liriodendri Gmelin (now Toumeyella liriodendri). The adult female of this scale insect is redescribed and illustrated from newly collected specimens in its native range and on its type host, the tulip tree, Liriodendron tulipifera L. (Magnoliales: Magoliaceae).

Neotype designation and redescription of Toumeyella liriodendri (Gmelin) (Hemiptera: Coccoidea: Coccidae)

Takumasa Kondo, and Douglas J. Williams

Neotype designation and redescription of Toumeyella liriodendri (Gmelin) (Hemiptera: Coccoidea: Coccidae)

Takumasa Kondo, and Douglas J. Williams

Neotype designation and redescription of Toumeyella liriodendri (Gmelin) (Hemiptera: Coccoidea: Coccidae)

Takumasa Kondo, and Douglas J. Williams

Neotype designation and redescription of Toumeyella liriodendri (Gmelin) (Hemiptera: Coccoidea: Coccidae)

Takumasa Kondo, and Douglas J. Williams

Neotype designation and redescription of Toumeyella liriodendri (Gmelin) (Hemiptera: Coccoidea: Coccidae)

Takumasa Kondo, and Douglas J. Williams

Neotype designation and redescription of Toumeyella liriodendri (Gmelin) (Hemiptera: Coccoidea: Coccidae)

Takumasa Kondo, and Douglas J. Williams

Neotype designation and redescription of Toumeyella liriodendri (Gmelin) (Hemiptera: Coccoidea: Coccidae)

Takumasa Kondo, and Douglas J. Williams

Neotype designation and redescription of Toumeyella liriodendri (Gmelin) (Hemiptera: Coccoidea: Coccidae)

Takumasa Kondo, and Douglas J. Williams

Neotype designation and redescription of Toumeyella liriodendri (Gmelin) (Hemiptera: Coccoidea: Coccidae)

Takumasa Kondo, and Douglas J. Williams

Neotype designation and redescription of Toumeyella liriodendri (Gmelin) (Hemiptera: Coccoidea: Coccidae)

Takumasa Kondo, and Douglas J. Williams

Molecular cloning and sequence analysis of a novel P450 gene encoding CYP345D3 from the red flour beetle, Tribolium castaneum

Hong-Bo Jiang, Jin-Jun Wang, Guo-Ying Liu, and Wei Dou

A novel cDNA clone encoding a cytochrome P450 gene has been isolated from the insecticide-susceptible strain of the red flour beetle, Tribolium castaneum (Herbst) (Coleoptera: Tenebrionidae). The nucleotide sequence of the clone, designated CYP345D3, was determined. The cDNA is 1554 bp in length and contains an open reading frame from base pairs 32 to 1513, encoding a protein of 493 amino acid residues and a predicted molecular weight of 57466 Daltons. The putative protein contains the classic heme-binding sequence motif FxxGxxxCxG (residues 430–439) conserved among all P450 enzymes as well as other characteristic motifs of the cytochrome P450s. Comparison of the deduced amino acid sequence with other CYP members shows that CYP345D3 shares 91% identity with the previously published sequence of CYP345D1 from the T. castaneum genome project and the nucleotide sequence identity between them is less than 80%. Phylogenetic analysis of amino acid sequences from members of various P450 families indicated close phylogenetic relationship of CYP345D3 with CYP6 of other insects than those from mammals and amore distant relationship to P450 from other families. CYP345D3 was submitted to GenBank, accession number EU008544.

Influence of temperature and humidity on the efficacy of spinosad against four stored-grain beetle species

In the present work, we examined the insecticidal effect of spinosad, against adults of the lesser grain borer, Rhyzopertha dominica (F.) (Coleoptera: Bostrychidae), the rice weevil, Sitophilus oryzae (L.) (Coleoptera: Curculionidae), the confused flour beetle, Tribolium confusum Jacquelin du Val (Coleoptera: Tenebrionidae) on wheat and the larger grain borer, Prostephanus truncatus (Horn) (Coleoptera: Bostrychidae) on maize. The dose rates used were 0.01, 0.1, 0.5 and 1 ppm. The bioassays were carried out at three temperatures, 20, 25 and 30 °C and two relative humidity levels, 55 and 75 %. Mortality of R. dominica and S. oryzae was high even at 0.01 ppm of spinosad, reaching 100 % at 55 % relative humidity and 30 °C after 21 days of exposure. Generally, mortality of R. dominica, increased with temperature while for S. oryzaemortality increased with temperature and with the decrease of relative humidity. Moreover, for S. oryzae, mortality was low at 20 °C. In the case of T. confusum, mortality was low at doses between 0.01 and 0.5 ppm even after 21 days of exposure. At 1 ppm, mortality exceeded 90 % only at 30 °C and only after 21 days of exposure. Mortality of P. truncatus was low on maize treated with 0.01 ppm, but increasing the dose to 0.1 ppm resulted in > 87 % mortality after 14 days of exposure. In several combinations tested, spinosad efficacy notably varied according to the temperature and humidity regimes. Of the species tested, R. dominica and P. truncatus were very susceptible to spinosad, followed by S. oryzae, while T. confusum was the least susceptible.

Neotype designation and redescription of Toumeyella liriodendri (Gmelin) (Hemiptera: Coccoidea: Coccidae)

Takumasa Kondo, and Douglas J. Williams

Neotype designation and redescription of Toumeyella liriodendri (Gmelin) (Hemiptera: Coccoidea: Coccidae)

Takumasa Kondo, and Douglas J. Williams

Neotype designation and redescription of Toumeyella liriodendri (Gmelin) (Hemiptera: Coccoidea: Coccidae)

Takumasa Kondo, and Douglas J. Williams

Neotype designation and redescription of Toumeyella liriodendri (Gmelin) (Hemiptera: Coccoidea: Coccidae)

Takumasa Kondo, and Douglas J. Williams

Neotype designation and redescription of Toumeyella liriodendri (Gmelin) (Hemiptera: Coccoidea: Coccidae)

Takumasa Kondo, and Douglas J. Williams

Neotype designation and redescription of Toumeyella liriodendri (Gmelin) (Hemiptera: Coccoidea: Coccidae)

Takumasa Kondo, and Douglas J. Williams

Neotype designation and redescription of Toumeyella liriodendri (Gmelin) (Hemiptera: Coccoidea: Coccidae)

Takumasa Kondo, and Douglas J. Williams

Neotype designation and redescription of Toumeyella liriodendri (Gmelin) (Hemiptera: Coccoidea: Coccidae)

Takumasa Kondo, and Douglas J. Williams

Neotype designation and redescription of Toumeyella liriodendri (Gmelin) (Hemiptera: Coccoidea: Coccidae)

Takumasa Kondo, and Douglas J. Williams

Neotype designation and redescription of Toumeyella liriodendri (Gmelin) (Hemiptera: Coccoidea: Coccidae)

Takumasa Kondo, and Douglas J. Williams

Neotype designation and redescription of Toumeyella liriodendri (Gmelin) (Hemiptera: Coccoidea: Coccidae)

Takumasa Kondo, and Douglas J. Williams

Neotype designation and redescription of Toumeyella liriodendri (Gmelin) (Hemiptera: Coccoidea: Coccidae)

Takumasa Kondo, and Douglas J. Williams

Neotype designation and redescription of Toumeyella liriodendri (Gmelin) (Hemiptera: Coccoidea: Coccidae)

Takumasa Kondo, and Douglas J. Williams

Neotype designation and redescription of Toumeyella liriodendri (Gmelin) (Hemiptera: Coccoidea: Coccidae)

Takumasa Kondo, and Douglas J. Williams

Neotype designation and redescription of Toumeyella liriodendri (Gmelin) (Hemiptera: Coccoidea: Coccidae)

Takumasa Kondo, and Douglas J. Williams

Neotype designation and redescription of Toumeyella liriodendri (Gmelin) (Hemiptera: Coccoidea: Coccidae)

Takumasa Kondo, and Douglas J. Williams

Neotype designation and redescription of Toumeyella liriodendri (Gmelin) (Hemiptera: Coccoidea: Coccidae)

Takumasa Kondo, and Douglas J. Williams

Neotype designation and redescription of Toumeyella liriodendri (Gmelin) (Hemiptera: Coccoidea: Coccidae)

Takumasa Kondo, and Douglas J. Williams

Neotype designation and redescription of Toumeyella liriodendri (Gmelin) (Hemiptera: Coccoidea: Coccidae)

Takumasa Kondo, and Douglas J. Williams

Neotype designation and redescription of Toumeyella liriodendri (Gmelin) (Hemiptera: Coccoidea: Coccidae)

Takumasa Kondo, and Douglas J. Williams

Neotype designation and redescription of Toumeyella liriodendri (Gmelin) (Hemiptera: Coccoidea: Coccidae)

Takumasa Kondo, and Douglas J. Williams

Neotype designation and redescription of Toumeyella liriodendri (Gmelin) (Hemiptera: Coccoidea: Coccidae)

Takumasa Kondo, and Douglas J. Williams

Neotype designation and redescription of Toumeyella liriodendri (Gmelin) (Hemiptera: Coccoidea: Coccidae)

Takumasa Kondo, and Douglas J. Williams

Neotype designation and redescription of Toumeyella liriodendri (Gmelin) (Hemiptera: Coccoidea: Coccidae)

Takumasa Kondo, and Douglas J. Williams

Neotype designation and redescription of Toumeyella liriodendri (Gmelin) (Hemiptera: Coccoidea: Coccidae)

Takumasa Kondo, and Douglas J. Williams

Neotype designation and redescription of Toumeyella liriodendri (Gmelin) (Hemiptera: Coccoidea: Coccidae)

Takumasa Kondo, and Douglas J. Williams

Neotype designation and redescription of Toumeyella liriodendri (Gmelin) (Hemiptera: Coccoidea: Coccidae)

Takumasa Kondo, and Douglas J. Williams

Neotype designation and redescription of Toumeyella liriodendri (Gmelin) (Hemiptera: Coccoidea: Coccidae)

Takumasa Kondo, and Douglas J. Williams

Neotype designation and redescription of Toumeyella liriodendri (Gmelin) (Hemiptera: Coccoidea: Coccidae)

Takumasa Kondo, and Douglas J. Williams

Neotype designation and redescription of Toumeyella liriodendri (Gmelin) (Hemiptera: Coccoidea: Coccidae)

Takumasa Kondo, and Douglas J. Williams

Neotype designation and redescription of Toumeyella liriodendri (Gmelin) (Hemiptera: Coccoidea: Coccidae)

Takumasa Kondo, and Douglas J. Williams

Neotype designation and redescription of Toumeyella liriodendri (Gmelin) (Hemiptera: Coccoidea: Coccidae)

Takumasa Kondo, and Douglas J. Williams

Neotype designation and redescription of Toumeyella liriodendri (Gmelin) (Hemiptera: Coccoidea: Coccidae)

Takumasa Kondo, and Douglas J. Williams

Neotype designation and redescription of Toumeyella liriodendri (Gmelin) (Hemiptera: Coccoidea: Coccidae)

Takumasa Kondo, and Douglas J. Williams

Neotype designation and redescription of Toumeyella liriodendri (Gmelin) (Hemiptera: Coccoidea: Coccidae)

Takumasa Kondo, and Douglas J. Williams

Neotype designation and redescription of Toumeyella liriodendri (Gmelin) (Hemiptera: Coccoidea: Coccidae)

Takumasa Kondo, and Douglas J. Williams

Neotype designation and redescription of Toumeyella liriodendri (Gmelin) (Hemiptera: Coccoidea: Coccidae)

Takumasa Kondo, and Douglas J. Williams

Neotype designation and redescription of Toumeyella liriodendri (Gmelin) (Hemiptera: Coccoidea: Coccidae)

Takumasa Kondo, and Douglas J. Williams

Neotype designation and redescription of Toumeyella liriodendri (Gmelin) (Hemiptera: Coccoidea: Coccidae)

Takumasa Kondo, and Douglas J. Williams

Neotype designation and redescription of Toumeyella liriodendri (Gmelin) (Hemiptera: Coccoidea: Coccidae)

Takumasa Kondo, and Douglas J. Williams

Neotype designation and redescription of Toumeyella liriodendri (Gmelin) (Hemiptera: Coccoidea: Coccidae)

Takumasa Kondo, and Douglas J. Williams

Molecular cloning and analysis of the tryptophan oxygenase gene in the silkworm, Bombyx mori

Liu Yan, Meng Zhi-Qi, Niu Bao-Long, He Li-Hua, Weng Hong-Biao, and Shen Wei-Feng

A Bombyx mori L. (Lepidoptera: Bombycidae) gene encoding tryptophan oxygenase has been molecularly cloned and analyzed. The tryptophan oxygenase cDNA had 1374 nucleotides that encoded a 401 amino acid protein with an estimated molecular mass of 46.47 kDa and a PI of 5.88. RT-PCR analysis showed that the B. mori tryptophan oxygenase gene was transcribed in all examined stages. Tryptophan oxygenase proteins are relatively well conserved among different orders of arthropods.

Odorant receptor c-terminal motifs in divergent insect species

Raymond Miller, and Zhijian Tu

Insect odorant receptors are a large family of seven transmembrane proteins believed to be G-protein coupled receptors. The peptide sequences of two odorant receptors within a given species may share as little as 17% identity, and there is limited similarity between receptors of divergent species. One exception is DmOr83b, which is found in Drosophila melanogaster and is highly conserved in at least ten other insect species. DmOr83b is broadly expressed in most of the olfactory sensory neurons of D. melanogaster at most developmental stages, while other odorant receptors tend to have more restricted and specific expression patterns. DmOr83b is critical for D. melanogaster olfaction, and it is involved in properly localizing other odorant receptors possibly by forming heterodimers with these receptors. The C-terminal region has been implicated as sites for such heterodimer formation. Multiple em for motif elicitation (MEME), a hidden markov model based program, was used to uncover three conserved motifs in the C-termini of a vast majority of the odorant receptor peptides from Anopheles gambiae, D. melanogaster, and Apis mellifera. These motifs are also found in DmOr83b and its orthologs and the order of these motifs is conserved as well. The conservation of these motifs among divergent odorant receptors in divergent species suggests functional importance. We propose that these motifs are involved in receptor- receptor protein interactions, contributing to the heterodimer formation between DmOr83b (or its orthologs) and other odorant receptors.

Foreign gene transfer in termite cells using a recombinant vesicular stomatitis virus

The Formosan subterranean termite, Coptotermes formosanus Shiraki, and the eastern subterranean termite, Reticulitermes flavipes (Kollar) (Isoptera: Rhinotermitidae), are well known for their destruction of human dwellings and flora in the tropics and subtropics. A method to deliver foreign genes into termite cell cultures would provide a controlled environment to facilitate the study of key regulatory functions at the molecular and cellular level. Here a method for the establishment and cryopreservation of primary embryonic termite cell cultures is described. Evidence is presented of viral-mediated gene transfer in these cells and foreign gene expression using a recombinant vesicular stomatitis virus vector.

Larval survival of Fuller’s rose weevil, Naupactus cervinus, on common groundcover species in orchards of New Zealand kiwifruit

David P. Logan, Bridget J. Maher, Shirley S. Dobson, and Patrick G. Connolly

Fuller’s rose weevil, Naupactus cervinus (Boheman) (Curculionidae: Entiminae), is an important quarantine pest of New Zealand kiwifruit exported to Asian markets. Both adults and larvae are considered to be polyphagous. In this study, the survival of larval N. cervinus was estimated on common groundcover species of kiwifruit (Actinidia spp.) in the Bay of Plenty, the main region in New Zealand where kiwifruit is grown. The botanical composition of groundcover in commercial kiwifruit orchards, characterised by survey, was dominated by ryegrass (Lolium perenne), with white clover (Trifolium repens), creeping buttercup (Ranunculus repens), wild strawberry (Duchesnea indica) and broadleaf dock (Rumex obtusifolius) in lower abundance. Survival to mature larvae or adult was relatively low (•11%) for N. cervinus introduced as neonates to field plots or potted ryegrass, white clover and broadleaf dock. White clover was a more favourable host for survival to adults than ryegrass. This study suggests that increased survival of N. cervinus larvae may occur where white clover and large dock plants are abundant, but that survival is likely to be highly variable because of the heterogeneous availability of preferred host plants and host plant quality. These data suggest that larval polyphagy is a strategy that enables N. cervinus to persist at low densities in kiwifruit orchards despite variation in the quality and diversity of groundcover.

Quinoa, Chenopodium quinoa, provides a new host for native herbivores in northern Europe: Case studies of the moth, Scrobipalpa atriplicella, and the tortoise beetle, Cassida nebulosa

Lene Sigsgaard, Sven Erik Jacobsen, and Jørgen Lindskrog Christiansen

The Andean grain, quinoa, Chenopodium quinoa Willd. (Caryophyllales: Amaranthaceae), is gaining increasing attention as a future food and fodder crop in Denmark and other parts of Europe. Prior to 2005, pest problems in the crop were negligible in Denmark, however native insects may become adapted to this new host. Herbivores feeding on the closely related and very common weed in arable crops Chenopodium album L. present a special risk. In 2006 there was a heavy attack of Scrobipalpa atriplicella (Röslerstamm) (Lepidoptera: Gelechiidae) larvae in the maturing inflorescence of C. quinoa. Gelechiidae are the most important pests on C. quinoa in the Andean region. In 2007 another herbivore on C. album, the tortoise beetle Cassida nebulosa L. (Coleoptera: Chrysomelidae), was a serious problem on C. quinoa in southern Jutland. This is the first published record of these two pests on C. quinoa. The future pest status of C. quinoa in northern Europe is discussed.

Susceptibility of eggs and adult fecundity of the lesser grain borer, Rhyzopertha dominica, exposed to methoprene

Y. Chanbang, F. H. Arthur, G. E. Wilde, J. E. Throne, and Bh. Subramanyam

A series of tests were conducted to determine the susceptibility of eggs and neonates of the lesser grain borer Rhyzopertha dominica (F.) (Coleoptera: Bostrichidae = Bostrychidae), exposed to the insect growth regulator, methoprene, on filter paper and on rough rice. In the first test, the hatch rate of eggs exposed on filter paper treated with methoprene at the label rate of 0.003 mg [AI] /cm2 when used as a surface treatment in structures was 52.0 ± 7.3% compared to 93.0 ± 3.3% on untreated controls. In the second test, eggs were exposed to a dose-response series of 0.00003 to 0.03 mg[AI]/cm2. Egg hatch was directly proportional to concentration and ranged from 85.0 ± 2.0% on untreated controls to 26.7 ± 8.3% at the highest concentration tested. In the third test, 1 ppm of methoprene was sprayed on long grain rough rice (paddy) (Cocodrie variety), and then individual kernels were cracked and an egg of R. dominica was placed directly on the kernel. On untreated rice kernels, 67.5 ± 11.6% of the eggs hatched and were able to bore inside, and all of these larvae emerged as adults. In contrast, 40.0 ± 5.3% of the eggs placed on treated cracked kernels were able to develop to where the larvae were visible through X-ray detection, but none emerged as adults. In the final test, newly-emerged adults were exposed on rough rice treated with 1 ppm methoprene. The number of eggs from adults on untreated rice was 52.1 ± 4.3 eggs per female, and on treated rice the average egg production was 12.5 ± 1.1 eggs per female. Methoprene applied on a surface or on rough rice affected development of egg hatch also reduced fecundity of parent adults exposed on the treated rough rice.

Latitudinal body size clines in the butterfly Polyommatus icarus are shaped by gene-environment interactions

Georg H. Nygren, Anders Bergström, and Sören Nylin

The study of latitudinal body size clines can illuminate processes of local adaptation, but there is a need for an increased understanding of the relative roles of genetic variation, environmental effects, and interactions between them, in shaping such geographical patterns. For this reason, we combined an investigation of a museum collection of the common blue butterfly Polyommatus icarus (Rottemburg) (Lycaenidae: Polyommatini) from Sweden with a common-garden experiment in the laboratory, using strains reared from individuals collected from three different latitudes. Sizes of the field-collected butterflies tended to smoothly decrease northwards in a latitudinal cline, but suddenly increase at the latitude where the life cycle changes from two to one generations per year, hence allowing more time for this single generation. Further north, the size of the field-collected butterflies again decreased with latitude (with the exception of the northernmost collection sites). This is in accordance with the "converse Bergmann" pattern and with the “saw-tooth model” suggesting that insect size is shaped by season length and number of generations along latitudinal transects. In contrast, under laboratory conditions with a constant long day-length there was a different pattern, with the butterflies pupating at a higher mass when individuals originated from southern populations under time stress to achieve a second generation. This is indirect evidence for field patterns being shaped by end-of-season cues cutting development short, and also suggests counter-gradient variation, as butterflies from the time-stressed populations over-compensated for decreasing larval development time by increasing their growth rates, thus obtaining higher mass. Hence, we found support for both adaptive phenotypic plasticity and local genetic adaptation, with gene-environment interactions explaining the observed field patterns.

Alkalinization in the isolated and perfused anterior midgut of the larval mosquito, Aedes aegypti

Horst Onken, Stacia B. Moffett, and David F. Moffett

In the present study, isolated midguts of larval Aedes aegypti L. (Diptera: Culicidae) were mounted on perfusion pipettes and bathed in high buffer mosquito saline. With low buffer perfusion saline, containing m-cresol purple, transepithelial voltage was monitored and luminal alkalinization became visible through color changes of m-cresol purple after perfusion stop. Lumen negative voltage and alkalinization depended on metabolic energy and were stimulated in the presence of serotonin (0.2 μmol l⁻¹). In some experiments a pH microelectrode in the lumen recorded pH values up to 10 within minutes after perfusion stop. The V-ATPase inhibitor concanamycin (50 μmol l⁻¹) on the hemolymph side almost abolished V_te and inhibited luminal alkalinization. The carbonic anhydrase inhibitor, methazolamide (50 μmol l⁻¹), on either the luminal or hemolymph-side, or the inhibitor of anion transport, DIDS (1 mmol l⁻¹) on the luminal side, had no effect on V_te or alkalinization. Cl⁻ substitution in the lumen or on both sides of the tissue affected V_te, but the color change of m-cresol purple was unchanged from control conditions. Hemolymph-side Na⁺ substitution or addition of the Na⁺/H⁺ exchange inhibitor, amiloride (200 μmol l⁻¹), reduced V_te and luminal alkalinization. Luminal amiloride (200 μmol l⁻¹) was without effects on V_te or alkalinization. High K⁺ (60 mmol l⁻¹) in the lumen reduced V_te without affecting alkalinization. These results indicate that strong luminal alkalinization in isolated and perfused anterior midgut of larval A. aegypti depends on basolateral V-ATPase, but is apparently independent of carbonic anhydrase, apical Cl⁻/HCO₃⁻ exchange or apical K⁺/2H⁺ antiport.

Host plant record for the fruit flies, Anastrepha fumipennis and A. nascimentoi (Diptera, Tephritidae)

Keiko Uramoto, David S. Martins, Rita C. A. Lima, and Roberto A. Zucchi

The first host plant record for Anastrepha fumipennis Lima (Diptera: Tephritidae) in Geissospermum laeve (Vell.) Baill (Apocynaceae) and for A. nascimentoi Zucchi found in Cathedra bahiensis Sleumer (Olacaceae) was determined in a host plant survey of fruit flies undertaken at the “Reserva Natural da Companhia Vale do Rio Doce”. This reserve is located in an Atlantic Rain Forest remnant area, in Linhares county, state of Espírito Santo, Brazil. The phylogenetic relationships of Anastrepha species and their hosts are discussed. The occurrence of these fruit fly species in relation to the distribution range of their host plants is also discussed.

Conglobation in the pill bug, Armadillidium vulgare, as a water conservation mechanism

Jacob T. Smigel, and Allen G. Gibbs

Water balance of the terrestrial isopod, Armadillidium vulgare, was investigated during conglobation (rolling-up behavior). Water loss and metabolic rates were measured at 18 ± 1°C in dry air using flow-through respirometry. Water-loss rates decreased 34.8% when specimens were in their conglobated form, while CO₂ release decreased by 37.1%. Water loss was also measured gravimetrically at humidities ranging from 6 to 75 %RH. Conglobation was associated with a decrease in water-loss rates up to 53 %RH, but no significant differences were observed at higher humidities. Our findings suggest that conglobation behavior may help to conserve water, in addition to its demonstrated role in protection from predation.

Repellent properties of δ-octalactone against the tsetse fly, Glossina morsitans morsitans

Martin T. Mwangi, Nicholas K. Gikonyo, and Isaiah O. Ndiege

δ-octalactone, produced by several Bovidae, has been suggested as a potential repellant of tsetse fly attack. Racemic δ-octalactone was synthesized via an abbreviated route. The product was assayed against 3-day old starved teneral female tsetse flies, Glossina morsitans morsitans Wiedemann (Diptera: Glossinidae), in a choice wind tunnel and found to be a potent tsetse repellent at doses ≥0.05 mg in 200 μl of paraffin oil (0.05 >p >0.01).

Isolation and characterization of a baculovirus associated with the insect parasitoid wasp, Cotesia marginiventris, or its host, Trichoplusia ni

James J. Grasela, Arthur H. McIntosh, Kent S. Shelby, and Steve Long

A multiple nucleopolyhedrovirus (MNPV) was isolated from Trichoplusia ni (Hübner) (Lepidoptera: Noctuidae) larvae that had been stung by the parasitoid Cotesia marginiventris (Cresson) (Hymenoptera: Braconidae). The wild type virus was plaque purified by infecting a Heliothis subflexa (BCIRL- HsAM1) cell line and isolating several clones. The mean estimated genomic size of this virus based on PstI, BstEII, StyI, HindIII restriction profiles was estimated to be 106 ± 2.5 kbp (mean±SE). A clone designated as TnMNPV/CmBCL9 was used in bioassays against several lepidopteran pests and in comparative studies with the baculoviruses AcMNPV, AgMNPV, AfMNPV, PxMNPV and HzSNPV of Autographa californica, Anticarsia gemmatalis, Anagrapha falcifera, Plutella xylostella, and Helicoverpa zea, respectively. Infectivity studies showed that TnMNPV/CmBCL9 was highly infectious for Heliothis subflexa and T. ni, with an LC₅₀ value 0.07 occlusion bodies/mm² in both species and also infectious for H. zea and Heliothis virescens with LC₅₀ values of 0.22 and 0.27 occlusion bodies/mm², respectively. Restriction endonuclease analysis of the isolate and selected baculoviruses revealed profiles that were very similar to AfMNPV but different from the restriction endonuclease profiles of the other baculoviruses. Hybridization studies suggest that the TnMNPV/CmBCL9 was closely related to AfMNPV and AcMNPV-HPP. Further support for this comes from a phylogenetic analysis employing a split-graphs network, comparing the polh, egt, and p10 genes from TnMNPV/CmBCL9 with those from other baculoviruses and suggests that this virus is closely related to the AcMNPV variants, AfMNPV and RoMNPV of Rachiplusia ou.

Production of Beauveria bassiana fungal spores on rice to control the coffee berry borer, Hypothenemus hampei, in Colombia

Francisco J. Posada-Flórez

Two isolates of fungal entomopathogen Beauveria bassiana (Balsamo) Vuillemin (Hypocreales: Clavicipitaceae) were grown on cooked rice using diphasic liquid-solid fermentation in plastic bags to produce and harvest spore powder. The cultures were dried and significant differences were found for isolates and time of harvest. The spores were harvested manually and mechanically and after the cultures were dried for nine days, when moisture content was near 10%. After harvesting, spores were submitted to quality control to assess concentration, germination, purity, moisture content, particle size and pathogenicity to the coffee berry borer, Hypothenemus hampei (Ferrari) (Coleoptera: Curculionidae). Spore productivity on cooked rice was less than 1x10¹⁰ spores/g using both manually and mechanically harvesting methodologies. Germination at 24 hours was over 75% and pathogenicity against H. hampei was over 92.5%. This methodology is suitable for laboratory and field studies, but not for industrial production when a high concentration of spores are required for formulation and field applications.

The basic helix-loop-helix transcription factor family in the honey bee, Apis mellifera

Yong Wang, Keping Chen, Qin Yao, Wenbing Wang, and Zhi Zhu

The basic helix-loop-helix (bHLH) transcription factors play important roles in a wide range of developmental processes in higher organisms. bHLH family members have been identified in a dozen of organisms including fruit fly, mouse and human. In this study, we identified 51 bHLH sequences in silico in the honey bee, Apis mellifera L. (Hymenoptera: Apidae), genome. Phylogenetic analyses revealed that they belong to 38 bHLH families with 21, 11, 9, 1, 8 and 1 members in high-order groups A, B, C, D, E and F, respectively. Using phylogenetic analyses, all of the 51 bHLH sequences were assigned to their corresponding families. Genes that encode ASCb, NeuroD, Oligo, Delilah, MyoRb, Figα and Mad were not found in the honey bee genome. The present study provides useful background information for future studies using the honey bee as a model system for insect development.

Fire ants, Solenopsis invicta, dry and store insect pieces for later use

Glivery G. Gayahan, and Walter R. Tschinkel

Whereas long-term storage of liquid food in the crops of worker ants and storage of dry seeds are well-known, widespread, and sometimes spectacular phenomena, there have been no previous reports documenting the storage of dead insect prey. Predacious ants typically devour their insect prey within a short time. Given a bonanza of insect prey, the fire ant, Solenopsis invicta, desiccates small pieces of these insects (creating insect “jerky”) and stockpiles these pieces in its mound, immediately below the mound surface, the driest and warmest location in the nest. Feeding colonies fluorescently dyed beetle larvae, and searching for fluorescence at night under ultraviolet light illumination verified such stockpiling. Stockpiles ranged from a few pieces to hundreds. Ant larvae in field colonies fed a single dose of dyed beetle larvae remained fluorescent for about two weeks. Laboratory colonies were fed a single dose of dyed larvae and then either starved of insect food, or fed on undyed larvae. All larvae in starved colonies remained strongly fluorescent for four weeks, whereas those in fed colonies gradually declined in fluorescence, showing that in the absence of an inflow of insect prey, workers in the starved colonies fed the dried insect fragments to larvae. Storage of dried food is easily overlooked, and it is possible that it is not limited to fire ants.

Interactions between population density of the Colorado potato beetle, Leptinotarsa decemlineata, and herbicide rate for suppression of solanaceous weeds

The presence of volunteer potato Solanum tuberosum L., cutleaf nightshade, S. triflorum N., and hairy nightshade, S. physalifolium Rusby (Solanales: Solanaceae), throughout potato crop rotations can diminish the effectiveness of crop rotations designed to control disease and pest problems associated with growing potatoes. In greenhouse bioassays, larvae of the Colorado potato beetle, Leptinotarsa decemlineata Say (Coleoptera: Chrysomelidae) were placed in population densities of 0, 5, 10, and 40 per potato (cv. Russet Burbank) plant and 0, 5, 10, and 15 per cutleaf nightshade and hairy nightshade plant. Plants were treated with different rates of herbicides including fluroxypyr, prometryn, and mesotrione rates, and the physiological response on the potato plants was assessed by weighing shoot biomass 14 days after treatment. Consistently, across all bioassays, rate response functions were shifted as L. decemlineata density increased, such that less herbicide was required to achieve control. For instance, the herbicide rate needed to achieve 90% reduction in potato biomass was reduced from 62 to 0 g fluroxypyr per hectare and 711 to 0 g prometryn per hectare as L. decemlineata density was increased to 40 larvae per plant. Herbivory at higher L. decemlineata population densities and herbicides above certain rates resulted in large reductions in cutleaf and hairy nightshade biomass. Differences in rate response functions among L. decemlineata population densities indicated that L. decemlineata contributed to weed suppression in combination with herbicides. These data suggest that integrated weed management systems targeting volunteer potato, cutleaf nightshade, and hairy nightshade can be more effective when herbicide applications are combined with herbivory by naturally occurring Colorado potato beetles.

A new click beetle genus from Southern Chile: Llanquihue (Coleoptera, Elateridae, Elaterinae, Pomachiliini)

Elizabeth T. Arias

Llanquihue, a new genus of Elateridae from Southern Chile, is here described and illustrated with 2 species: Llanquihue vittipennis (Candèze) new comb., and L. carlota sp. nov. The genus Llanquihue belongs to the subfamily Elaterinae and to the tribe Pomachiliini.

Environmental determinants of the distribution and abundance of the ants, Lasiophanes picinus and L. valdiviensis, in Argentina

Paula Fergnani, Paula Sackmann, and Fabiana Cuezzo

The distribution and abundance variation of the terrestrial ants, Lasiophanes picinus and Lasiophanes valdiviensis Emery (Formicinae: Lasiini), which are endemic in Patagonia (Argentina and Chile), are described and a set of environmental factors are examined to explain the observed patterns. Ants were collected using 450 pitfall traps arranged in 50, 100 m² grid plots each with nine traps within a roughly 150 × 150 km area representative of the subantartic-patagonian transition of Argentina. Five sampling periods each 8-days long were carried out between November 2004 and March 2006. To understand the distributional patterns and their link to environmental variables discriminant analysis was used. Path analysis was performed to test for direct and indirect effects of a set of environmental variables on species abundance variation. L. picinus was more frequently captured and attained higher abundance in the forests, while L. valdiviensis was more frequently captured and more abundant in the scrubs. The maximum daily temperature and mean annual precipitation explained L. picinus distribution (i.e. presence or absence) with an accuracy of 90%. L. valdiviensis distribution was predicted with almost 70% accuracy, taking into account herbal richness. The maximum daily temperature was the only climatic variable that affected ant abundance directly; an increase in temperature led to an increase of L. picinus abundance and a decrease of L. valdiviensis abundance. The amount of resources, as indicated by the percent plant cover, explained the variation of the abundance of both species better than the variety of resources as indicated by plant richness (i.e. models including plant richness had low fit or no fit at all). A direct effect of habitat use by cattle was found, as indicated by the amount of feces in the plots, only when variables related to the amount of resources were replaced by variables with less explanatory power related to the variety of resources. This study provides new data on the ecology of Lasiophanes species in relation to existing hypotheses proposed to explain patterns of abundance variation. Evidence is provided that changes in temperature (i.e. global climate change) may have important consequences on populations of these species.

Morphology and histology of the ductus receptaculi and accessory glands in the reproductive tract of the female cricket, Teleogryllus commodus

Robert Sturm

The morphology and histology of the ductus receptaculi and accessory glands in females of the black field cricket, Teleogryllus commodus Walker (Orthoptera: Gryllidae) are described. Both are reproductive organs situated in the 7^th and 8^th abdominal segment that join the posterior part of the genital chamber. The ductus receptaculi is a long (up to 25 mm) homogeneous tube, and the accessory glands (total length: 4 to 12 mm) are a complex system of tubes and end lobes with various numbers of ramifications. Based on their external shapes the accessory glands may be subdivided into three distinct regions, a distal region mainly producing the gland’s secretion, a middle conducting region, and a basal region serving for the storage and release of the secretory substances into the genital chamber of the female. In histological respects, both organs have an outer muscle coat followed by a basal lamina, one or two cell layers, the cuticular intima, and the inner lumen. The ductus receptaculi is subdivided into three histologically different regions. The region located adjacent to the receptaculum and the region neighbouring the terminal papilla consist of a single, epithelial cell layer that is not secretory. The epithelium of the middle region contains two cell layers, glandular cells and cuticula-forming cells, which are responsible for the production of the cuticular intima. The secretion of the gland cells is released into an extracellular cavity, through which it reaches the lumen via a complex network of canals running through the intima. The histology of the accessory glands is rather homogeneous among the different regions, as one layer of epithelial cells produces both the secretion and the cuticular intima. Histological variations in the distal, middle, and basal gland sections mainly concern the height of the epithelium, the thickness of the basal lamina and the cuticular intima as well as the variable presence of the outer muscle coat. In contrast to the ductus receptaculi, secretory substances produced by the accessory gland cells accumulate in the lumen by a diffusive permeation of the intima.

Detection of the bacterium, Xylella fastidiosa, in saliva of glassy-winged sharpshooter, Homalodisca vitripennis

Jose L. Ramirez, Paulo T. Lacava, and Thomas A. Miller

Homalodisca vitripennis (Germar) (Hemiptera: Cicadellidae), the glassy-winged sharpshooter, is one of the most important vectors of the bacterium, Xylella fastidiosa subsp. piercei (Xanthomonadales: Xanthomonadaceae) that causes Pierce’s Disease in grapevines in California. In the present study we report a new method for studying pathogen transmission or probing behavior of H. vitripennis. When confined, H. vitripennis attempt to probe the surface of sterile containers 48 hours post-acquisition of X. f. piercei. The saliva deposited during attempted feeding probes was found to contain X. f. piercei. We observed no correlation between X. f. piercei titers in the foregut of H. vitripennis that fed on Xylella-infected grapevines and the presence of this bacterium in the deposited saliva. The infection rate after a 48 h post-acquisition feeding on healthy citrus and grapevines was observed to be 77% for H. vitripennis that fed on grapevines and 81% for H. vitripennis that fed on citrus, with no difference in the number of positive probing sites from H. vitripennis that fed on either grapevine or citrus. This method is amenable for individual assessment of X. f. piercei-infectivity, with samples less likely to be affected by tissue contamination that is usually present in whole body extracts.

Reference gene selection for insect expression studies using quantitative real-time PCR: The head of the honeybee, Apis mellifera, after a bacterial challenge

In this study an important and often neglected aspect of gene expression studies in insects, the validation of appropriate reference genes with stable expression levels between sample groups, is addressed. Although in this paper the reference gene selection for the honeybee, Apis mellifera L. (Hymenoptera: Apidae) head was tested in the context of bacterial challenge with Escherichia coli, this work can serve as a resource to help select and screen insect reference genes for gene expression studies in any tissue and under any experimental manipulation. Since it is recommended to use multiple reference genes for accurate normalization, we analyzed the expression of eleven candidate reference genes in the honeybee head, for their potential use in the analysis of differential gene expression following bacterial challenge. Three software programs, BestKeeper, Normfinder and geNorm, were used to assess candidate reference genes. GeNorm recommended the use of four reference genes. Both geNorm and Normfinder identified the genes GAPDH, RPS18, actin and RPL13a as the most stable ones, only differing in their ranking order. BestKeeper identified RPS18 as being the reference gene with the least overall variation, but also actin and GAPDH were found to be the second and third most stable expressed gene. By a combination of three software programs the genes actin, RPS18 and GAPDH were found suitable reference genes in the honeybee head in the context of bacterial infection.

The effects of hydration on growth of the house cricket, Acheta domesticus

Kevin E. McCluney and Rishabh C. Date

Maintenance of biochemical gradients, membrane fluidity, and sustained periods of activity are key physiological and behavioral functions of water for animals living in desiccating environments. Water stress may reduce the organism’s ability to maintain these functions and as such, may reduce an organism’s growth. However, few studies have examined this potential effect. The effects of altered hydration state of the house cricket, Acheta domesticus L. (Orthoptera: Gryllidae) on individual growth were studied under laboratory conditions. Crickets were permitted access to water for three different durations each day, resulting in significant differences in hydration state (32% greater hydration for maximum than minimum duration of water availability). Growth was 59% and 72% greater in dry mass and length, respectively, between the lowest and highest hydration state treatments. These findings may be representative for a variety of animal species and environments and could have important ecological implications.

Dynamic thermal structure of imported fire ant mounds

James T. Vogt, Bradley Wallet, and Steven Coy

A study was undertaken to characterize surface temperatures of mounds of imported fire ant, Solenopsis invicta Buren (Hymenoptera: Formicidae) and S. richteri Forel, and their hybrid, as it relates to sun position and shape of the mounds, to better understand factors that affect absorption of solar radiation by the nest mound and to test feasibility of using thermal infrared imagery to remotely sense mounds. Mean mound surface temperature peaked shortly after solar noon and exceeded mean surface temperature of the surrounding surface. Temperature range for mounds and their surroundings peaked near solar noon, and the temperature range of the mound surface exceeded that of the surrounding area. The temperature difference between mounds and their surroundings peaked around solar noon and ranged from about 2 to 10°C. Quadratic trends relating temperature measurements to time of day (expressed as percentage of daylight hours from apparent sunrise to apparent sunset) explained 77 to 88% of the variation in the data. Mounds were asymmetrical, with the apex offset on average 81.5 ± 1.2 mm to the north of the average center. South facing aspects were about 20% larger than north facing aspects. Mound surface aspect and slope affected surface temperature; this affect was greatly influenced by time of day. Thermal infrared imagery was used to illustrate the effect of mound shape on surface temperature. These results indicate that the temperature differences between mounds and their surroundings are sufficient for detection using thermal infrared remote sensing, and predictable temporal changes in surface temperature may be useful for classifying mounds in images.

Cloning and phylogenetic analysis of sid-1-like genes from aphids

Weina Xu, and Zhaojun Han

The sid-1 (systemic interference defective) gene encodes a transmembrane protein that is an important participator in the systemic RNAi pathway and has been reported in several organisms. In insects, sid-1-like genes were described from Tribolium castaneum, Apis mellifera, Bombyx mori and Schistocerca americana, but were not found in Drosophila melanogaster and Anopheles gambiae. To investigate whether this gene occurs in aphid species, RT-PCRs were performed using degenerate primers designed using the conserved motif of sid-1-like genes. An sid-1-like full-length transcript was amplified from the cotton/melon aphid, Aphis gossypii Glover (Homopera: Aphididae), and a fragment was amplified from the grain aphid, Sitobion avenae (F.). The trancript from A. gossypii was 3067 bp long, with an open reading frame encoding 766 amino acids. Sequence analysis indicated that this transcript shares highest similarity with the reported sid-1-like gene in Schistocerca americana (53%, fragment), followed by A. mellifera (44%), T. castaneum (32–44%), B. mori (38–42%) and Caenorhabditis elegans (25%). Analysis of the transmembrane protein topological structure indicated that the protein encoded by this gene has a similar structure to SID-1 of C. elegans. A phylogenetic tree with all available sid-1-like genes suggests that sid-1-like genes may have had a long evolutionary history. Considering its importance in the RNAi pathway, the absence of a sid-1-like gene in D. melanogaster and A. gambiae is worthy of further investigation.

Ovicidal activity of organophosphate, oxadiazine, neonicotinoid and insect growth regulator chemistries on the northern strain plum curculio, Conotrachelus nenuphar

Eric J. Hoffmann, Samantha M. Middleton, and John C. Wise

An in vitro method was developed for assessing ovicidal effects of the organophosphate azinphos-methyl, the neonicotioids thiacloprid, thiamethoxam and clothianidin, the oxadiazine indoxacarb and the insect growth regulators novaluron and pyriproxifen on the plum curculio, Conotrachelus nenuphar (Herbst)(Coleoptera: Curculionidae). The baseline survivorship of this method was 88 percent. Plum curculio eggs were most sensitive to azinphos-methyl. Thiacloprid, clothianidin and the chitin synthesis inhibitor, novaluron, had LC₅₀ values below 100 ppm. Thiamethoxam, indoxacarb and pyriproxifen were not ovicidal at 100 ppm. Octanol-water partitioning coefficients, log K_ow, appeared to be an important indicator of ovicidal activity within the neonicotinoids. This new bioassay method eliminates the confounding of the insect-chemical and plant-chemical interactions and the results highlight the utility of a post-infestation curative approach to plum curculio management.

Effect of plant structure on searching strategy and searching efficiency of Trichogramma turkestanica

Daniel Gingras, Pierre Dutilleul, and Guy Boivin

When searching for hosts on a plant, female parasitoids use strategies to maximize efficiency. Searching strategies include the expressed behaviors, the time budget associated with each behavior, the time allocated to the different plant parts and the exploration sequence of plant parts. Searching efficiency refers to the time taken to find the first egg, the number of eggs found per foraging time unit and the re-encountering frequency of eggs during a foraging period. This study examines the effect of artificial simple (few leaves and connections) and complex plant structures (more leaves and connections) on searching strategy and searching efficiency of the egg parasitoid Trichogramma turkestanica Meyer (Hymenoptera: Trichogrammatidae). Analyses of frequency and duration of behaviors associated with searching on artificial plants of different complexities were performed. Plant structure had no effect on time associated with locomotion behaviors such as walking, standing and flying. However, it had an impact on the area searched, which was significantly greater on simple plant structure. Also, time spent on a leaf without encountering an egg was greater on complex plant structure compared to simple one. No significant differences were found between simple and complex plant structures regarding time spent walking on the different plant parts such as twigs, limbs, leaf perimeters, and limbs of inferior and superior leaf sides. Results showed that female parasitoids spent less time actively exploring complex than simple plants. Encountering and re-encountering frequencies of eggs were significantly greater on simple than on complex plant structure. Plant structure had no effect on handling time of eggs. This study demonstrates that plant structure can modulate activities inherent to searching and ovipositing, which in turn affects area searched per foraging time unit and therefore host finding success.

Molecular cloning and expression of three polygalacturonase cDNAs from the tarnished plant bug, Lygus lineolaris

Margaret L. Allen and Jeffrey A. Mertens

Three unique cDNAs encoding putative polygalacturonase enzymes were isolated from the tarnished plant bug, Lygus lineolaris (Palisot de Beauvois) (Hemiptera: Miridae). The three nucleotide sequences were dissimilar to one another, but the deduced amino acid sequences were similar to each other and to other polygalacturonases from insects, fungi, plants, and bacteria. Four conserved segments characteristic of polygalacturonases were present, but with some notable semiconservative substitutions. Two of four expected disulfide bridge–forming cysteine pairs were present. All three inferred protein translations included predicted signal sequences of 17 to 20 amino acids. Amplification of genomic DNA identified an intron in one of the genes, Llpg1, in the 5′ untranslated region. Semiquantitative RT-PCR revealed expression in all stages of the insect except the eggs. Expression in adults, male and female, was highly variable, indicating a family of highly inducible and diverse enzymes adapted to the generalist polyphagous nature of this important pest.

Extensive natural intraspecific variation in stoichiometric (C:N:P) composition in two terrestrial insect species

S. M. Bertram, M. Bowen, M. Kyle, and J. D. Schade

Heterotrophic organisms must obtain essential elements in sufficient quantities from their food. Because plants naturally exhibit extensive variation in their elemental content, it is important to quantify the within-species stoichiometric variation of consumers. If extensive stoichiometric variation exists, it may help explain consumer variation in life-history strategy and fitness. To date, however, research on stoichiometric variation has focused on interspecific differences and assumed minimal intraspecific differences. Here this assumption is tested. Natural variation is quantified in body stoichiometry of two terrestrial insects: the generalist field cricket, Gryllus texensis Cade and Otte (Orthoptera: Gryllidae) and a specialist curculionid weevil, Sabinia setosa (Le Conte) (Coleoptera: Curculionidae). Both species exhibited extensive intraspecific stoichiometric variation. Cricket body nitrogen content ranged from 8–12% and there was a four-fold difference in body phosphorus content, ranging from 0.32–1.27%. Body size explained half this stoichiometric variation, with larger individuals containing less nitrogen and phosphorus. Weevils exhibited an almost three-fold difference in body phosphorus content, ranging from 0.38–0.97%. Overall, the variation observed within each of these species is comparable to the variation previously observed across almost all terrestrial insect species.

Habitat characteristics and eggshell distribution of the salt marsh mosquito, Aedes vigilax, in marshes in subtropical eastern Australia

Research at 10 locations in coastal subtropical Queensland, Australia, has shown that salt marshes contained heterogeneous distributions of eggshells of the pest and vector mosquito Aedes vigilax (Skuse) (Diptera:Culicidae). The eggshell distribution was related to specific vegetation assemblages, with a mix of the grass, Sporobolus virginicus (L.) Kunth (Poales: Poaceae), and the beaded glasswort, Sarcocornia quinqueflora (Bunge ex (Ung.-Stern) A.J. Scott (Caryophyllales: Chenopodiaceae), as significantly higher in eggshells than any other vegetation. There were also high numbers in the mix of S. virginicus with the arrowgrass, Triglochin striata Ruiz & Pavón (Alismatales: Juncaginaceae). Both mixed types are found in relatively wetter areas, despite very few eggshells being found generally in the low marsh. Most sites contained S. virginicus and eggshell locations were variable for this species alone. This was probably related to its life form variability in response to salinity and location on the marsh. Location on the marsh was important for eggshell distribution with most eggshells around the edges of pools and depressions, followed by, but to a significantly lesser extent, the marsh surface. Eggshells were fewest in the low marsh. Partition analysis resulted in a tree that simplified and summarised the factors important for eggshell distribution confirming the individual analyses. The potential effects of climate, sea level and other change are also briefly discussed in the context of likely changes to land cover and relative location on the marsh. For example, increased sea level may lead to low marsh conditions extending into higher marsh area with implications for oviposition and numbers of eggshells.

Effects of heat shock on survival and reproduction of two whitefly species, Trialeurodes vaporariorum and Bemisia tabaci biotype B

Xuhong Cui, Fanghao Wan, Ming Xie, and Tongxian Liu

The effects of heat shock on survival and reproduction of two whitefly species, Trialeurodes vaporariorum (Westwood) and Bemisia tabaci (Gennadius) biotype B (Homoptera: Aleyrodidae), were compared in the laboratory. Whitefly adults were exposed to 26 (control), 37, 39, 41, 43 and 45°C for 1 hour, and were then maintained at 26°C. Adult survival was significantly affected when they were exposed at 41°C or higher for B. tabaci or 39°C or higher for T. vaporariorum. All males of T. vaporariorum were killed at 45°C. In both whitefly species, females were more tolerant to high temperatures at 39°C or higher than males. Female fecundity was not significantly different when B. tabaci adults were heat-shocked at all temperatures. In contrast, the fecundity of T. vaporariorum females declined with the increase of temperature, and only a few eggs were oviposited at 43°C. Survival or hatch rates of the F1 nymphs of both whitefly species declined as heat-shock temperature increased, and no T. vaporariorum nymphs were hatched at 43°C. Similarly, percentages of F1 offspring developing to adults for both whitefly species also declined as the heat-shock temperature increased. Sex ratios of the F1 offspring were not significantly affected for T. vaporariorum but were slightly affected for B. tabaci at 43 and 45°C. The significance of heat shock in relation to dispersal, distribution and population dynamics of the two whitefly species is discussed.