Some have proposed that the evolution of ultrasound as a male courtship cue in milkweed tussocks has arisen stepwise through transitional stages of redundant courtship cues (both pheromone and ultrasound). Furthermore, it has been proposed that ultrasound courtship was evolutionarily linked to a switch to cardenolide-producing larval host plants. To test the hypothesis of a transitional stage and proposed correlation of the behavior with larval hosts, the phylogenetic relationships of the phaegopterines Euchaetes, Cycnia, Ectypia, Pygarctia, and Pareuchaetes were assessed with 88 characters (205 states) derived from adult morphology. The resulting strict consensus placed the Pareuchaetes among the outgroup genera and recovered the remaining four genera as a clade. Euchaetes was not monophyletic; however, removal of Pareuchaetes results in monophyly. Based on this phylogeny, the ancestor of the ingroup clade fed on cardenolide-containing host plants, possessed well developed tymbals and lacked coremata (pheromone distributing structures). Thus, the use of male ultrasound in courtship was correlated with larval feeding on cardenolide hosts. The hypothesis that ultrasound first arose as a redundant courtship cue, with a subsequent loss of the male pheromone, was not supported by our data. Rather, male pheromone courtship was reacquired after ultrasound courtship in two lineages, based on the presence of coremata and behavioral data.

Larvae of Andex insignis Sharp (Coleoptera: Adephaga: Dytiscidae) are described. A parsimony analysis of selected taxa of Hydroporinae based on 24 informative larval characters was conducted using the program PAUP*. The 20 most parsimonious trees support a placement of Andex Sharp within the tribe Hyphydrini as part of a clade made up of Desmopachria Babington Hyphydrus Illiger Prismopes Sharp, which is supported by the presence of dorsal metafemoral and mesofemoral setae. Larvae of Andex evolved three unique character states within the Hyphydrini: the presence of several dorsal secondary setae on the prementum, the presence of three frontoclypeal lateral processes in instar III, and the absence of the primary pore TIa.

The harpactorine reduviid genus Sinea is represented in the midwestern United States by three species: Sinea complexa Caudell, Sinea diadema (F.), and Sinea spinipes (Herrich-Schaeffer). Although the nymphs of these species have been described, no key has been developed for their identification. Here, we present a key to the nymphs of these taxa to the species and instar levels.

Distribution and biotypes of Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae) in eastern Asia are not clear. In this study, B. tabaci was collected from Taiwan and neighboring islands of eastern Asia. Host range records included 51 plant species from 15 families. The molecular marker of the mitochondrial cytochrome oxidase I (COI) gene sequence was used to distinguish biotypes. Phylogenetic analyses indicated three biotypes in eastern Asia: B, Nauru, and An. This is the first molecular evidence to demonstrate the B and An biotypes in Taiwan and that the Nauru and An biotypes are new to China. Therefore, at least the B, Q, Nauru, and An biotypes are now known from China. Phylogenetic trees revealed that the invasion event of the B biotype in Taiwan was recent, and multiple invasions may have occurred due to human trade activities. The B biotype is the most widely distributed biotype in Taiwan. Invasions by the Nauru and An biotypes in Taiwan may have included both natural movements and human trade activities. Otherwise, distributions of the Nauru and An biotypes overlap in Asia, and it is presumed they are closely related. The result supports that the Nauru biotype is of Asian origin, and the An biotype may be of Asian or Australian origin. In addition, the tree topology supports B. tabaci being differentiated into three major clades: the New World, Asia/Australia, and Mediterranean/Asia Minor/African groups. This study also provides some information on the relationships within the B. tabaci species complex. In addition, we hope this study will be helpful to crop protection and appropriate control materials of B. tabaci in eastern Asia.

The five species of Cybocephalidae in America north of Mexico are revised. Included are redescriptions of Cybocephalus californicus Horn, Cybocephalus nigritulus LeConte, and Cybocephalus nipponicus Endrödy-Younga and descriptions of two new species, Cybocephalus kathrynae and Cybocephalus randalli. A key to species, illustrations of morphological features, including detailed drawings of male genitalia, distribution data, and host lists are provided. The confusion involving Cybocephalus nipponicus and Cybocephalus binotatus Grouvelle is discussed and the differences between them are made evident.

The two existing keys (Fox 1895 and Bohart 2000) to the New World species of Sphecius (Dahlbom 1843) do not correctly identify a large percentage of female Sphecius convallis (Patton 1879) and Sphecius grandis (Say 1824). Both keys fail to allow for common variations in the number of gastral segments with yellow markings, and one key has the two species reversed. Here, we present an improved key that correctly identifies both sexes of >4,400 specimens of New World Sphecius, which we examined.

RESUMEN Las dos llaves existentes (Fox 1895 y Bohart 2000) de la especie del Nuevo Mundo de Sphecius (Dahlbom 1843) no determinan correctamente un gran porcentaje de las hembras de Sphecius convallis (Patton 1879), y S. grandis (Say 1824). Ambas llaves faltan en acomodar las variaciones comunes en el numero de segmentos gastrales de coloracion amarilla, y uno tiene las dos especies invertidas. Aqui presentamos una llave mejorada que correctamente identifica los dos sexos de mas que 4,400 especimenes de Sphecius del Nuevo Mundo que hemos examinado.

The genetic similarity of New and Old World samples of Spalangia spp. (Hymenoptera: Pteromalidae) was examined using two ribosomal DNA regions. The species examined were Spalangia cameroni Perkins, Spalangia endius Walker, Spalangia gemina Bouc˘ek, Spalangia nigra Latreille, Spalangia nigroaenea Curtis, and Spalangia slovaca Bouc˘ek. Two species of Muscidifurax, Muscidifurax raptor Girault & Sanders and Muscidifurax zaraptor Kogan & Legner (Hymenoptera: Pteromalidae) were included as outgroup taxa. The internal transcribed spacer (ITS)-1 region was highly variable among Spalangia species with many insertions/deletions making alignment of the sequences difficult. The D2-D3 region of the 28s ribosomal gene and the nuclear rDNA 18s gene were more conserved and enabled phylogenetic analysis. No genetic differentiation was observed among S. cameroni and S. endius samples from Kazakhstan, Russia, and North America. New World samples of S. nigroaenea are genetically distinct from S. slovaca, a morphologically similar Old World species that is newly recorded from Kazakhstan and Russia. The intact 920 bp ITS-1 amplicon of S. nigroaenea was much larger than the 780-bp amplicon of S. slovaca. Kimura two-parameter genetic distance between the two species was 0.015 for the 28s region. Otherwise, the smallest genetic distance among recognized Spalangia species was 0.037 between S. endius and S. nigra. The genetic distance between M. raptor and M. zaraptor was 0.004. Based upon these results, the utility of the D2-D3 region of the 28s ribosomal gene is substantiated for differentiating species of Spalangia. The molecular analysis of the six Spalangia species revealed two groupings: S. nigroaenea and S. slovaca and S. cameroni and S. gemina. A third clade, S. endius and S. nigra, was observed, but bootstrap support was weak. These relationships were compared with those indicated by morphology and all agreed except possibly between S. endius and S. nigra, for which morphological evidence is equivocal. Morphological features are described and illustrated to distinguish the morphologically most similar species, S. nigra, S. nigroaenea, and S. slovaca, from each other and from other Spalangia spp.

The literature on herbivorous insects in heterogeneous habitats has addressed insect population responses to patch size, distance from source populations, habitat edges, and variation in host stem density. Studies typically conclude that insect colonists respond positively to the area of host plant patches, but there is little consensus on how insects respond to variation in host density at the patch level. Although observed variation likely results partially from differences in study species and focal habitats, deviations from expectations also may reflect the importance of unmeasured habitat parameters. In this study of colonization by cicada Magicicada cassinii (Fisher) in an experimentally fragmented old field, we simultaneously examined landscape variation in patch size, distance from the sources of colonization, and local host plant stem density (at a within-patch scale) and also considered edge effects. Per stem colonization was positively related to proximity to the population source and habitat patch size but negatively related to local host stem density. The effect of edge was nonsignificant. When coarser scale estimates of local stem density (calculated by averaging the figures for all quadrats within patches) were used in analyses, fewer significant main effects were found and sometimes interactions occurred. Our study highlights the importance of including all potential explanatory variables in analyses, with what we feel is a novel observation that the explicit consideration of fine-scale, within-patch variation in local stem density can be important to the interpretation of insect dispersal and colonization.

The life history and production of Caenis latipennis Banks (Ephemeroptera: Caenidae) is described from Honey Creek, Oklahoma. Emergence behavior, fecundity, voltinism, and secondary production were analyzed. C. latipennis had an extended emergence with five peaks. Females emerged, molted, mated, and oviposited in an estimated 37 min. Mean fecundity was 888.4 ± 291.9 eggs per individual (range, 239–1,576). Adult female head capsule widths in spring were significantly larger than in summer and fall. Compared with the other seasons, fecundity was significantly higher in early summer when densities were lowest. C. latipennis exhibited a multivoltine life cycle with five overlapping generations. Estimated annual secondary production for C. latipennis in Honey Creek was 4,404.28 mg/m²/yr, mean standing stock biomass was 274.64 mg/m²/yr, cohort production:biomass ratio was 5.79, and the annual production/biomass rate was 16.04/yr/yr. Standing stock biomass ranged from 7.6 to 705.4 mg/m² during the year. Standing stock biomass did not vary significantly among seasons.

Volume is a proxy for biomass in hard-bodied arthropods. We constructed a highly significant overall equation relating biomass and volume for Neotropical dung beetles (Scarabaeidae). In addition, we constructed separate equations for 12 Neotropical genera of scarabs, of which 11 were highly significant. In general, linear functions explained the relationship between biomass and volume equally well as log-transformed data. In addition, we tested the effects of alcohol storage on volume over the course of a year and found no significant change in dung beetle volume. Because scarab volume is not affected by alcohol storage up to a period of 1 yr, the biomass–volume equations we have provided for fresh specimens may be valid to quantify biomass of specimens stored in alcohol.

We determined the effect of body size and adult female longevity on the realized fecundity and fertility of the large aspen tortrix, Choristoneura conflictana (Walker) (Lepidoptera: Tortricidae), an outbreaking forest lepidopteran. We examined these relationships from an ecological perspective and included the impact of age at pairing and infection with a microsporidian pathogen in our analyses. The relationship between body size, as measured by pupal weight and forewing length and area, and realized fecundity and fertility was best for healthy females that were paired immediately after eclosion. A delay in age of pairing or sublethal pathogen infection eroded these relationships. A delay in age of pairing resulted in a lower percentage of females that produced fertile eggs and a significant reduction in the number of eggs laid. Although sublethal pathogen infection indirectly disrupted the body size-realized fecundity and fertility relationship, infection did not directly decrease egg production. Wing area was the best predictor of total and fertile egg production. The relationship between pupal weight and wing area was correlated, but females eclosing from small pupae had proportionately larger wings than females from large pupae, which may indicate a cost of large body mass in this actively dispersing species. Longevity of females did not predict the total or fertile number of eggs laid by females. There was no consistent relationship between pairing treatment and longevity of female moths, suggesting that there is no trade-off between longevity and reproductive fitness in this species. Sublethal pathogen infection significantly decreased female moth longevity, but this decrease was not reflected in reduced fecundity of infected females. Our data illustrate that although body size is an important determinant of realized fecundity and fertility in C. conflictana, these relationships are mediated by several factors that may vary greatly under field conditions and at varying population densities.

The gall fly Cecidochares connexa (Macquart) (Diptera: Tephritidae) was imported from Indonesia into Guam in 1998. It was field-established at one location in north central Guam, and its spatial and temporal spread in Guam was monitored. The biology of the gall fly is presented. No relationship between the number of larvae in a gall and the dimensions of the gall (length and width) existed. Three pupae per gall was the most frequent density with a range of 1–7. The sex ratio of flies emerging from galls was 1:1 irrespective of number of larvae per gall. C. connexa-induced galls established a “nutrient sink” as a result of the formation of a nutritive tissue along the walls of the larval chamber. Younger galls contained more mineral nutrients, namely, calcium, iron, potassium, manganese, and zinc, which were depleted as the galls matured, but the reverse trend was noted for sodium. Galls developing on terminal meristems significantly reduced the length of the shoots of Chromolaena odorata (Asteraceae).

The nonphotosynthetic orchid Gastrodia elata Blume (Orchidaceae) is a mycoheterotroph associated with the wood-decomposing fungus Armillaria mellea. Here, we report the symbiotic and parasitic associations of some insects with this orchid. The flowers are nectarless and were visited by females of a halictid bee, Lasioglossum sp. The bees entered the tubular flower and collected the tissue from the orchid’s labellum. Pollinia were attached to the hind thorax of the bee and transported to the stigma of receptive flowers. The stems and corms of the orchid were infested by two rare dipterans, Azpeytia shirakii Hurkmans (Syrphidae) and a new genus and species of scatophagid, Orchidophaga gastrodiacola n. sp. M. Kato. Adult flies of the latter species laid eggs in the flower. The hatched larvae infested the immature ovary, bored downward into the flowering stem, and occasionally entered the underground corms. The high rate of infestation by these dipterans suggests that the robust flower stem of the orchid has evolved as counteradaptation against these particular stem-boring dipterans. A molecular phylogenetic analysis suggests that O. gastrodiacola belongs to Delininae, which is one of the basal groups of Scatophagidae.

Compounds in the dorsal abdominal glands (DAGs) of adults and nymphs, and exuviae of two scentless plant bugs Leptocoris abdominalis (F.) and Leptocoris augur (F.) (Heteroptera: Rhopalidae), were studied by gas chromatography-mass spectrometry. For both species, two dorsal abdominal glands (median and posterior glands) are found in the nymphs, whereas in adults only the posterior gland is functional and the median gland is reduced. Monoterpenes are the major compounds in posterior glands for both species. For L. abdominalis β-pinene is most abundant monoterpene and for L. augur, limonene is most abundant monoterpene. Alkenals and alkenoic acids were found in median glands of both species. There was no sexual dimorphism in the morphology and the contents of the DAGs of adults. Analysis of the compounds found in the exuvia indicated that components in the median gland were shed with the exuvia. Quantitative analysis of the major monoterpenes and alkenals in the DAGs of different ages of L. abdominalis supported the observation that components in the posterior gland were retained in the insect after each molting. Possible functions of the components in the DAGs are discussed.

Description of colors of insects and plants in biological research is often subjective and imprecise. A quantitative, statistical, and standardized method for describing colors by software analysis of digital images would be useful to researchers if readily available. An Internet Web page with JavaScript and Java applet was made that loads a digital image and analyzes the red, green, and blue (RGB) intensity components of the pixels in any rectangular area of relatively uniform color. A mean, standard deviation (SD), coefficient of variation, and percentage of each of the three color components in the area is calculated. Thus, a colored area in an image can be depicted objectively as R ± SD, G ± SD, and B ± SD, or percentages thereof, allowing mean color to be reproduced elsewhere by paint programs. For each analysis, the software uses the RGB component colors to make a bar graph with each RGB value and SD. The software was used to analyze colors of flowers and leaves of two cotton species, white and red varieties of upland, Gossypium hirsutum L., and Pima, Gossypium barbadense L. (Malvaceae); western tarnished plant bug, Lygus hesperus Knight (Heteroptera: Miridae); yellow plastic used in insect traps; and eight other insect species. Three two-dimensional (2D) color-space diagrams (hexagon, 2D-cube, and ternary percentages) are described and used to plot colors from analyses. Statistical tests are presented that compare whether two groups of color-space points in three dimensions are significantly separated. Differences in color vision are compared in humans, insects, digital cameras, and spectroradiometers.

On the basis of head capsule widths of field-collected larvae, Cosmopolites sordidus (Germar) (Coleoptera: Curculionidae) was found to have five instars. Mean head capsule widths were 0.44, 0.71, 1.04, 1.48, and 1.85 mm for the first to fifth instars, respectively. The greatest growth ratio was recorded between the first and second instar. Adult C. sordidus densities reached a peak in January with 2.4 adults per trap, and the lowest density recorded was during April with 0.7 adults per trap. Adult captures seems to be influenced by precipitation with higher captures after precipitation events.

The first representative of the leafhopper tribe Proconiini (subfamily Cicadellinae), Anacuerna centrolinea (Melichar) is reported herein from the Tarapacá region in northern Chile. This species was discovered at high elevation (≈4,000 m) in the course of a survey conducted in South America by the USDA–ARS for the neoclassical biological control program against the glassy-winged sharpshooter, Homalodisca coagulata (Say) in California. New data are given on the biology and host plants of A. centrolinea. Information also is provided on its egg parasitoid, Gonatocerus tuberculifemur (Ogloblin) (Hymenoptera: Mymaridae) which also was a first record from Chile. This discovery encourages further exploration for leafhopper egg parasitoids in northern and central regions of Chile to identify new perspective biological control agents that are more adapted to Mediterranean climate (winters and wet summers), which are similar to California climate. In addition, it is possible that G. tuberculifemur may be a good candidate for the biological control of the recently discovered H. coagulata in Easter Island, Chile.

Xylella fastidiosa is a bacterial plant pathogen that causes many plant diseases, including Pierce’s disease of grapevines. Sharpshooter leafhopper (Hemiptera: Cicadellidae: Cicadellinae) vectors transmit this bacterium to plants. Although the basic mechanism of pathogen transmission is not completely understood, previous studies implicated the foregut of infected insects as the source of bacterial inoculum because infective nymphs lose transmissibility after molting and no latent period is required for transmission. Scanning electron microscopy documented the spatial distribution of X. fastidiosa in the foreguts of the sharpshooter Graphocephala atropunctata (Signoret) after short (1-d) and long (4-d) acquisition access periods on infected plants and various inoculation access periods on grape test plants. After 1-d acquisition and 1-d inoculation periods, cells had only colonized portions of the precibarium between the stylets and the cibarial pump, often embedded in a matrix-like material. After long (15-d) periods after acquisition, we found bacterial cells attached polarly to the insect’s cuticle in a regular pattern throughout the precibarium but absent from specific locations on both pharynges. Insects sampled for microscopy 2 wk after long acquisition access periods and that contained bacteria in their mouthparts transmitted X. fastidiosa to healthy grapevines independently of the length of the acquisition access period. In contrast, individuals free of bacteria on the precibarium did not transmit the pathogen. After successive short acquisition and inoculation periods, 5 of 12 X. fastidiosa-positive insects did not transmit to plants. We also did transmission experiments with the sharpshooter Homalodisca coagulata; however, only one of 30 individuals had X. fastidiosa attached to its precibarium, and none transmitted it to plants. Our results suggest that sharpshooters introduce into plants X. fastidiosa cells that detach from the precibarial canal during feeding.

A medium-sized nest of the Texas leafcutting ant, Atta texana (Buckley), in northern Louisiana was excavated completely, and a three-dimensional model of its external and subterranean features was constructed. In total, 97 fungus gardens, 27 dormancy cavities, and 45 detritus cavities were located. At the lower center of the funnel-shaped nest was a large central cavity, which in winter functions as a domicile for the colony and where the alate brood is reared. Vertical tunnels, possibly as deep as 32 m, may serve as wells leading to the water table. Winter mean annual temperatures within the central cavity may limit the northern geographical range of A. texana to ≈33° N latitude. The inquilines Attaphila fungicola Wheeler, Pholeomyia comans Sabrosky, Ceuthophilus sp., Lobopoda subcuneatus Campbell, Geomysaprinus nr. formicus (Hinton), species of Aleocharinae, and a species of Annelida were seen in nest cavities and galleries.

Electroantennogram (EAG) and behavioral responses of female oriental fruit moth, Grapholita molesta (Busck) (Lepidoptera: Tortricidae), were studied using the synthetic major component, (Z)-8-dodecenyl acetate, and partial three-component blend, (Z)-8-dodecenyl-acetate:(E)-8-dodecenyl-acetate:(Z)-8-dodecenol (in a 93:6:1 ratio), of the sex pheromone. EAGs elicited by both the single and three-component pheromone were significantly greater compared with hexane solvent controls. In 1-liter plastic chambers with constant throughput of air (50 ml/min) over rubber septa loaded with 0.01 or 0.1 mg of the three-component pheromone blend, onset of female calling was advanced by ≈2 h compared with solvent controls. However, the total number of females calling at peak time and the time of calling termination did not differ between pheromone-exposed and control moths. Oviposition rates of pheromone-exposed and clean air-exposed mated female moths did not differ in similar 1-liter flow-through chambers lined with wax paper over 24-h intervals. In a separate experiment, male and female oriental fruit moth, caged in perforated 1-liter containers allowing air ventilation, were placed for 1-wk intervals in replicated glasshouses that were either treated with Isomate dispensers hung 0.5 m from chambers or left untreated. Oviposition rates between Isomate dispenser-exposed and control moths were similar. Female sensitivity to sex pheromone, termed “autodetection,” has been observed previously and is thought to function either as a mechanism to 1) advance female calling periodicity under high population densities to increase the probability of attracting males, 2) induce dispersal under high population densities to reduce competition for males or food resources, or 3) aggregate females to increase local probability of mating success. Autodetection also may affect the efficacy of mating disruption for oriental fruit moth depending on whether pheromone exposure affects the diel periodicity of male sexual response.

The physiological action of pheromone biosynthesis activating neuropeptide (PBAN) on isolated pheromone glands of Helicoverpa zea (Boddie) (Lepidoptera: Noctuidae) was investigated with regard to the role of the Ca² channel in stimulating pheromone biosynthesis. A dose–response profile indicated that the minimum level of PBAN stimulation was achieved at 10⁻¹¹ M. PBAN activity requires the influx of extracellular Ca² . A time delay of up to 7.5 min from receptor activation by PBAN and influx of extracellular Ca² was determined. These results indicate that activation of the PBAN-receptor maintains the activation of a Ca² channel for a period of time. Similar results were found using transfected Sf9 cells expressing the cloned PBAN-receptor. This indicates that the Sf9 cells have a Ca² channel that is coupled to the receptor in a similar way as in the pheromone gland cells. To determine the type of Ca² channel, isolated glands were incubated with PBAN and organic Ca² channel blockers. L-type voltage-gated Ca² or nonselective Ca² channel blockers did not inhibit pheromone production. However, quinidine, a potassium channel blocker, inhibited pheromone production. These results indicate that the receptor-activated Ca² channel in the pheromone gland may not be a voltage-activated Ca² channel but rather a nonselective ion channel. Our results provide further insight into the action of PBAN with regard to the Ca² channel in the signal transduction of pheromone biosynthesis in moths.

Regeneration is a process of rebuilding damaged or disrupted cells and tissues. The insect’s midgut epithelium becomes damaged by passage of the food mass and by secretory processes. The regeneration process occurs differently in two related species belonging to the primitive wingless insect group Zygentoma: Thermobia domestica (Packard) (Thysanura: Lepismatidae) and Lepisma saccharina L. (Thysanura: Lepismatidae). In T. domestica, the degenerated cells are replaced in a continuous manner by newly formed cells originating from regenerative cell groups. In L. saccharina, the midgut epithelium is totally removed and numerous regenerative cell groups form the new epithelium simultaneously in a cyclical manner. Regenerative cells, being responsible for all regenerative mechanisms, fulfill the role of primordial cells of the midgut epithelium. Here, I describe the process of degeneration and regeneration of the midgut epithelium in these two species at the transmission electron microscope level.

A study of Chrysoperla carnea (Stephens) (Neuroptera: Chrysopidae) midgut structures and contents was conducted using scanning and transmission electron microscopy. The larval midgut was enclosed by a peritrophic membrane that seemed to be composed of two layers. Numerous bacteria were found throughout the lumen of the midgut, and because the midgut does not open to the hindgut, we hypothesized that the bacteria may serve to decompose the residues occurring in the midgut lumen. Few yeast cells were present in the larval midgut. The visual observations suggest that the concentration of bacteria were much lower in adult midguts than in larval midguts. However, many yeast cells were observed in the lumen of the adult midgut. No obvious peritrophic membrane was observed in electron micrographs of the adult midgut compared with the larval midgut. The results suggest different modes of food residue disposal.

The anatomy and histology of female Homalodisca coagulata (Say) (Hemiptera: Cicadellida: Proconiini) reproductive organs is described using light microscopy. The reproductive organs of H. coagulata consist of one pair of ovaries, each with 10 telotrophic ovarioles, a pair of lateral oviducts, a common oviduct, a spermatheca, an enlarged genital duct, a complex bursa copulatrix, a vagina, two types of accessory glands, and a genital chamber. The reproductive organs follow the general pattern seen in cicadellids. The complex bursa copulatrix, important in copulation and sperm transfer, is described. A set of morphological criteria were selected, based on the stage of oocyte development, and used to evaluate and assign the rank of ovarian development for field-collected individuals and to assess the overall reproductive status of female insect populations. A principal component analysis of morphological and physiological characteristics suggests that the ovarian ranks reflect the reproductive status of the females. Understanding reproductive status and patterns is critical for determining the optimal time to implement control methods to suppress H. coagulata populations in southern California.

Insect eggs are often characterized by an intricately sculptured external surface, which has been used to a limited extent as a taxonomic character, but not at all in comparisons among populations within a species or among populations of closely related species. We describe egg morphology by using scanning electron microscopy from 12 populations within a species complex of host-specific butterflies in the family Lycaenidae. Variation is found among populations and habitats. Adaptive hypotheses are discussed, and the observed variation is placed within the biogeographical context of the Sierra Nevada Mountains and adjacent regions.

Ten sclerotized morphological structures were measured to determine the number of instars of the linden borer, Saperda vestita Say (Coleoptera: Cerambycidae). Linear regression analysis revealed a significant relationship between maximal cranial width and the other structures measured, including length of the terminal labial palpomere, length of the first thoracic spiracle, width of the first thoracic spiracle, length of clypeolabral suture, length of frontoclypeal suture, cranial width measured at antennal insertions (from outside edges), maximal prothoracic width, mesal pronotal length, and length from apical margin of labrum to distal end of the prothorax. Linden borer instar number was determined through the use of frequency distribution diagrams. Mean, standard error of the mean, Dyar’s ratio, and Crosby’s ratio were calculated and evaluated for each instar designation to confirm that none of the five to six instars of S. vestita was overlooked.

It is assumed that geographic isolation of Dendroctonus Erichson species populations or their plant hosts determines genetic structure. This structure can be analyzed with respect to the biogeographic pattern that describes the species in a region. The Trans-Mexican Volcanic Belt (TMVB) is located between the Neartic and Neotropical regions and is a center of diversification and endemism of trees in the genus Pinus L. Dendroctonus mexicanus Hopkins is polyphagous within Pinus species and has a continuous geographic distribution across the TMVB. We explored whether the population genetic structure of D. mexicanus is reflective of the distribution pattern of the Dendroctonus species that occur in the TMVB. Twelve gene loci were analyzed by isozyme electrophoresis in 17 populations found on pines from the Leiophyllae subsection. Allele frequencies, average heterozygosity, heterozygosity by locus, deviations from Hardy–Weinberg equilibrium (HWE), F-statistics among populations, and average genetic flow were calculated. Genetic structure was determined using the relationship between F_ST versus geographic distances among populations. Genetic relations among populations were established by neighbor-joining and principal components analysis by using Nei’s genetic distances. Dendrogram reliability was assessed by bootstrap analysis and cophenetic correlation coefficient by using the Mantel test. Results show that heterozygosity of D. mexicanus is similar to other scolytids. A high proportion of loci were out of HWE by homozygous excess, which may be explained by multiple factors. The scarce number of fixed alleles, the allele variation pattern, pairwise genetic distances, and F-statistics suggest a model of isolation by distance for D. mexicanus in the TMVB resulting from recent dispersal events.

The Chinese population genetic structure of the twospotted spider mite, Tetranychus urticae Koch (Acari: Tetranychidae), was investigated by amplifying and sequencing a portion (453 bp) in the mitochondrial DNA gene coding for cytochrome oxidase I (COI). The study was aimed at checking genetic difference among the Chinese populations of the mite and analyzing its possible dispersal within China. Thirteen populations from east, west, northeast, northwest, and central parts of mainland China were sampled. In the comparisons of these sequences, 36 nucleotide positions (7.9% of the total length) were found polymorphic, of which 88.9% were silent substitutions. Intraspecific variation analysis showed that the Xinjiang (XJ) sample differed from the other samples by an average of 4.68% nucleotide divergence, which was represented two different phylogenetic lineages in the phylogenetic tree. Apart from the XJ sample, the other samples displayed little variation (nucleotide divergences below 1.77%) with each other and clustered in one of the lineages. We argue that the reasons for the remarkable distinction are probably geographical barriers and the use of different host plants.

The wild-type eye color of the horn fly, Hematobia iritans (L.) (Diptera: Muscidae), is a dark reddish brown. An apparent spontaneous mutation in a single adult colony fly resulted in a white-eyed mutant. A colony of white-eyed horn flies was established from this single individual and has been maintained in the laboratory. Laboratory crosses determined that the white-eyed phenotype is inherited as a simple Mendelian autosomal recessive with complete penetrance. No other differences from the wild-type flies were detected in the external characteristics of the mutant phenotype or in egg viability. However, white-eyed flies had significantly lower amounts of the pigment dihydroxyxanthommatin in their heads, suggesting either the lack of xanthommatin production, or a failure of transport and storage within the head of the mutant phenotype.

The affect of Hz-2V (a.k.a. gonad-specific virus) virus infection on the reproductive physiology and behavior of infected adult Helicoverpa zea (Boddie) (Lepidoptera: Noctuidae) males was examined. Virus-infected males responded and flew to calling healthy and infected females at about the same rate. Although infected males were slower in approaching healthy females and attempting to mate compared with healthy males, infected males did make sexual contacts with females that could serve to transmit virus. Unlike matings with healthy males, which result in the cessation of calling, females that had made sexual contact with infected males continued to exhibit calling behavior and were receptive to mates. Although calling behavior of both healthy and infected females was inhibited by injecting extracts of reproductive tissues from healthy males, extracts of reproductive tissues from infected males inhibited female calling to a lesser degree and for an additional night compared with extracts from healthy males. The results presented here further demonstrate the ability of Hz-2V to alter the physiology and behavior of infected insects in ways that could serve to facilitate virus transmission.

We investigated the influence of the presence of large males on the mating tactics of small males of the stink bug Megacopta punctatissima (Montandon) (Hemiptera: Plataspidae) by using laboratory experiments. In the presence of large males, the mating acceptance rate of females (the proportion of copulating males to the number of courting males) and the mating success (the proportion of copulating males to the total number of males) of large males were significantly higher than those of small males. Therefore, sexual selection favors larger male body size at mating. Although only 15.4% of small males courted females in the presence of large males, 57.5% of small males courted females in the absence of large males. Consequently, the mating success of small males was conspicuously higher in the absence of large males than in the presence of large males. We suggest that small males adopt an alternative mating strategy in which their courtship behavior is the same as that of large males, but their decision to court females depends on the presence or absence of large rival males.

In most katydids, females listen to and locate a stationary, singing male for mating. Pair formation differs in phaneropterine katydids where pairs form duets and the male typically finds the female after hearing her acoustic reply to his song. We recorded the duetting behavior of two cryptic species of phaneropterines, Amblycorypha rotundifolia (Scudder) and Amblycorypha alexanderi Walker (Tettigoniidae: Phaneropterinae), from populations in their zone of sympatry. The songs of the two species differed in their temporal properties, and the duets differed in the timing of the female’s replies with respect to the male’s song. We also measured the hearing sensitivity and auditory tuning in these species by recording extracellular neural responses to sound stimuli varying in frequency and intensity. Individuals of both species were most sensitive to frequencies near 13 kHz, which corresponds to the frequencies of the males’ calling songs and to the peak frequency in the females’ tick responses. Both species also responded to pulses with ultrasonic carrier frequencies. For higher amplitude stimuli, neural responses had shorter latencies and more action potentials. Latency functions differed for low-frequency and high-frequency stimuli. These data form the basis for understanding how auditory processing and sexual selection might be involved in the recent divergence of these two cryptic species.