Phenology and abundance of bean leaf beetles, Cerotoma trifurcata (Förster), were examined throughout two eastern South Dakota growing seasons in relation to grain yields in chisel-and ridge-tilled soybeans [Glycine max (L.) Merrill] grown in 2-yr rotation with corn (Zea mays L.) with and without added nitrogen (N). Populations were also sampled early and late season in alfalfa (Medicago sativa L.). Beetles were present in alfalfa by late May and most were reproductively active within a week, but their presence in alfalfa did not always precede soybean emergence. Most beetles taken from alfalfa in late fall were teneral; all were previtellogenic and unmated. Reproductively active beetles were detected in soybeans as soon as seedlings emerged. A partial second generation apparently occurred each year. First-generation beetles started to emerge in soybean fields during the first or third week of July but, whether emergence started early or late, most beetles emerging after July seemingly failed to mature their eggs and started leaving soybeans within several weeks of eclosion. This pattern suggested that any second generation arose from only the earliest emerging beetles of the first generation, with later emerging individuals having to overwinter before reproducing. Thus, any factors delaying emergence of the first generation, such as delayed soybean planting, could potentially limit its reproductive capacity through winter mortality. Cumulative seasonal beetle counts were lower in N-treated subplots and in ridge-tilled compared with chisel-tilled plots. Soybean grain yield increased with decreases in peak abundance of first-generation beetles and with N fertilization.

In a 3-yr study involving saltcedar-free, saltcedar-infested, and burned habitats in a riparian area at Lake Meredith, TX, the number of carabid species collected, diversity indices, and indicator species varied significantly among habitats. A 3-yr average of 15, 14, and 24 carabid species were collected from the saltcedar-free, saltcedar-infested, and burned habitats, respectively. Values for species richness, Shannon's and Simpson's diversity indices, and evenness index for pooled data collected from 2005 to 2007 were higher in the burned habitat followed by the saltcedar-free habitat and the saltcedar-infested habitat. Within-year parameters across the three habitats generally followed the pooled data results with some variation. Nonmetric multidimensional scaling analyses clearly indicated groups of carabid species preferred specific habitats. Five species in the burned area had indicator species percentage values >50% (Agonum punctiforme, Agonum texanum, Brachinus alternans, Harpalus pensylvanicus, and Poecilus chalcites). In the saltcedar-infested and saltcedar-free habitats, only one species in each habitat had indicator species percentage values that exceeded 50%; Calathus opaculus and Cicindela punctulata punctulata, respectively.

Biological invasions by nonnative plant species are a widespread phenomenon. Many studies have shown strong ecological impacts of plant invasions on native plant communities and ecosystem processes. Far fewer studies have examined effects on associated animal communities. From the perspective of a reserve's land management, I addressed the question of whether arthropod assemblages on two nonnative plant species of concern were impoverished compared with those assemblages associated with two predominant native plant species of that reserve. If the nonnative plant species, Conium maculatum L., and Phalaris aquatica L., supported highly depauperate arthropod assemblages compared with the native plant species, Baccharis pilularis De Candolle and Leymus triticoides (Buckley) Pilger, this finding would provide additional support for prioritizing removal of nonnatives and restoration of natives. I assessed invertebrate assemblages at the taxonomic levels of arthropod orders, Coleoptera families, and Formicidae species, using univariate analyses to examine community attributes (richness and abundance) and multivariate techniques to assess arthropod assemblage community composition differences among plant species. Arthropod richness estimates by taxonomic level between native and nonnative vegetation showed varying results. Overall, arthropod richness of the selected nonnative plants, examined at higher taxonomic resolution, was not necessarily less diverse than two of common native plants found on the reserve, although differences were found among plant species. Impacts of certain nonnative plant species on arthropod assemblages may be more difficult to elucidate than those impacts shown on native plants and ecosystem processes.

Creating conditions that enhance the abundance of resident populations of natural enemies in agroecosystems is considered critical to the efficiency of biological control of insect pests. We conducted a study to determine the potential of relay-intercropping for enhancing the abundance of aphidophagous lady beetles in sorghum. A relay-intercropping system consisting of alfalfa, winter wheat, and cotton as intercrops and sorghum as a main crop was compared with sorghum monoculture plots at two study sites in OK from 2003 to 2006. Lady beetles and aphids were sampled throughout the season using sticky traps and field counts on individual sorghum plants. Results from sticky traps and field counts show that differences in abundance and species composition of lady beetles between intercropped and monoculture sorghum were not statistically different during each year of study. Also, the lady beetle—greenbug ratios in relay-intercropped and monoculture plots were not significantly different. Lack of significant effects of relay-intercropping in our study may have been attributable to the confounding effects of spatial and temporal scale and the low number of aphids and other alternative prey in the intercrops compared with high incidence of corn leaf aphids in sorghum early in the season.

Livestock grazing can affect habitat quality for grasshoppers through effects on food and oviposition site availability, microclimate, and other factors. Because of this, some authors have suggested that grazing programs can be used to help manage pest grasshopper populations. In a 6-yr study, we controlled access of cattle to replicated experimental plots on an Agropyron spicatum/Poa sandbergii pasture to create consistent year-to-year differences in postgrazing plant cover, with resultant affects on microclimate. After sampling grasshoppers multiple times after grazing treatments each summer, we found evidence of between-treatment differences in grasshopper abundance for the entire assemblage during 4 of the 6 yr. Some species, including Melanoplus sanguinipes (perhaps the worse rangeland grasshopper pest in the western United States), tended to be more abundant on ungrazed plots, whereas Melanoplus gladstoni often had greater densities on heavily-grazed plots. The effect of grazing on grasshopper densities in this study was lower in magnitude and less consistent among years than in a study we conducted simultaneously at a nearby site where the vegetation was dominated by the exotic species crested wheatgrass (Agropyron cristatum). Our results generally support proposals that grazing could be used to reduce pest grasshopper densities, although the effectiveness of a particular grazing scheme may vary among sites, years, and grasshopper and vegetation assemblages.

Gall wasps (Hymenoptera: Cynipidae) induce structures (galls) on their host plants that house developing wasps and provide them with protection from natural enemies. The Asian chestnut gall wasp, Dryocosmus kuriphilus Yasumatsu, is an invasive pest that is destructive to chestnut (Castanea spp.). An improved understanding of the interactions among D. kuriphilus, its host, and its natural enemies is critical for the development of effective management strategies against this pest. The objective of our study was to evaluate the D. kuriphilus community interactions, and relate these interactions to variations among gall traits. Galls were collected from four locations throughout the eastern United States from May (gall initiation) through August (after gall wasp emergence), and January. Gall characteristics (volume, weight, and schlerenchyma layer thickness), gall inhabitants (D. kuriphilus, parasitoids, and chamber fungi), and other community associates (insect herbivores and lesions thought to be caused by endophytes) were evaluated and correlated using canonical correlation analyses. The primary mortality factors for D. kuriphilus were parasitism, gall chamber-invading fungi, and failure of adult gall wasps to emerge. Larger gall size and thicker schlerenchyma layers surrounding the larval chambers were negatively correlated with parasitoids and chamber fungi, indicating these gall traits are important defenses. External fungal lesions and insect herbivory were positively correlated with the absence of D. kuriphilus within galls. This study provides support for the protective role of cynipid galls for the gall inducer, identifies specific gall traits that influence gall wasp mortality, and improves our knowledge of D. kuriphilus ecology in North America.

Studies that consider both biotic and abiotic determinants of organisms are rare, but critical to delineate underlying determinants of community richness (number of taxa) and abundance (number of larvae per water body). In this study, we consider the importance of disturbance (salinity) and predator and competitor variables on mosquitoes (Diptera: Culicidae) in small ephemeral water bodies across the Wheatbelt of Western Australia. Similar to mosquitoes, and contrary to general perceptions, nonculicid aquatic fauna (aquatic fauna) had a common occurrence (number or percentage of water bodies occupied) and were abundant (average density) in ephemeral water bodies, albeit with a simplified trophic structure. The occurrence and density (number per unit area) of aquatic fauna between water bodies were highly variable, but general relationships of aquatic fauna with rainfall, water body surface area, salinity, and mosquitoes were apparent. In contrast to mosquitoes, the density of aquatic fauna declined with recent rainfall, implying mosquitoes may colonize newly created water bodies more quickly than aquatic fauna. Assemblages (richness and density of taxa) of aquatic fauna changed along a salinity gradient, as did mosquitoes, and this was pronounced for predator groups. Densities of mosquitoes were not limited by any single taxonomic group, by a negative relationship. However, the density and richness of mosquitoes generally declined in association with increased richness of predators and density of all other taxa (taxa not specifically classified as predators or competitors of mosquitoes). These relationships may account for higher densities of mosquitoes in smaller water bodies, where richness of predators is reduced and the density of other taxa does not differ from larger water bodies. Our results also suggest salinity in the Western Australia Wheatbelt may facilitate greater abundance of halotolerant mosquitoes, Aedes alboannulatus Macquart and Aedes camptorhynchus Thomson (a vector of Ross River virus [Togoviridae: Alphavirus]), by releasing them from biotic regulation.

Tswalu Kalahari Reserve is a private game reserve covering 1,020 km² in the Northern Cape, South Africa. It has been created from a number of reclaimed farms and restocked with large indigenous mammals. Two surveys were conducted to inventory the dung beetle fauna (Coleoptera: Scarabaeidae: Scarabaeinae) and determine their spatial patterns and food type associations. The spatial survey used pig dung—baited pitfall traps to examine dung beetle distribution across three main landscape types (plains, dunes, hills) comprising six principal vegetation communities. The food study examined their relative associations with carrion and four different dung types within a single vegetation community. A total of 70 species was recorded. Because the food association study was spatially restricted and conducted under drought conditions, abundance and species richness (47 species) were much lower than in the spatial study (64 species), which was conducted after substantial rainfall. Principal spatial differences in species abundance structure of assemblages were between the sandy southwest plains and dunes; the sandy northern dune fields and plains; and the rocky hills. Forty species analyzed in the food association study showed clear distributional biases to carrion or the dung of elephant (monogastric herbivore), pig (omnivore), cattle and sheep (ruminant herbivores), or pig and cattle. The results (1) show how dung beetle assemblage structure is locally diversified across the heterogeneous landscape of the reserve and (2) indicate how the different dung types dropped by a diverse assemblage of indigenous mammals may variously favor different species of dung beetles.

Individual lodgepole pines (Pinus contorta) were fertilized with urea at nitrogen (N) inputs equivalent to 0, 315, or 630 kg/ha. Four months after application of the fertilizer, inner bark tissue N concentrations were significantly higher in the trees that had received the low dose (315 kg/ha) fertilization treatment than in the control trees; trees that had received the high-dose treatment (630 kg/ha) were intermediate and not significantly different from either of the other treatments. There was a significant positive correlation between N concentration in inner bark tissue and larval mountain pine beetle, Dendroctonus ponderosae (Coleoptera: Curculionidae, Scolytinae). In vitro studies on synthetic growth media examined effects of temperature and N concentration on N concentration of two common fungal associates of the mountain pine beetle (Ophiostoma clavigerum and Ophiostoma montium). Increasing N concentration in growth media significantly increased fungal N concentrations in both O. clavigerum and O. montium. Furthermore, N concentration was consistently higher in O. clavigerum than in O. montiun. Neither species had sufficient growth at 30°C, nor did O. clavigerum at 15°C, to test N concentration. However, for O. montium, increasing temperatures decreased fungal N concentrations. There was no correlation between N concentration of O. clavigerum and growth temperature. Potential impacts of ingestion of the fungal species by developing mountain pine beetle larvae-infesting trees under various environmental conditions such as increasing temperatures are discussed.

We conducted an ant-exclusion experiment in a citrus orchard to evaluate the overall impact of three ant species native in the Mediterranean, Pheidole pallidula (Nylander), Plagiolepis schmitzii Forel, and Lasius grandis (Forel), on populations of Aonidiella aurantii Maskell (California red scale). The ant-exclusion was carried out in four experimental plots from March 2007 to November 2008. Another subset of four plots, adjacent to the ant-excluded plots, was used as control. We measured scale densities and percent parasitism on fruits at harvest in 2007 and 2008. Additionally, we sampled the seasonal trend of the scale on twigs and fruits in both treatments during 2008. California red scale densities in the ant-excluded treatment began to be significantly lower than in the ant-allowed control in May (1 mo after ant activity began), and this difference increased until November. Thus, the effect of the ants on California red scale density seems to be accumulative. At harvest, scale densities on fruits were significantly lower in the ant-excluded treatment. However, percent parasitism on fruits was similar between treatments. Finally, scale densities on the fruits of the ant-allowed plots were positively correlated with the number of ants that climbed to the citrus canopy. These results suggest that increases of scale densities induced by Mediterranean ants depend on the intensity of the ant-activity on citrus canopies.

Misotermes mindeni Disney and Neoh is a solitary endoparasitoid of Macrotermes gilvus (Hagen) (Termitidae: Macrotermitinae), exclusively parasitizing the head of major soldiers. In this study, behavioral and morphological changes in the parasitized termite host were evaluated. We also observed the larval parasitoid emerging from the host. We found that parasitism mainly occurred in termite mounds overgrown with grass and mounds that had been broken up previously for other experiments. The parasitized soldiers showed a significantly lower level of interspecific aggressiveness compared with healthy soldiers (P < 0.05). Parasitized soldiers also changed in habitat preference to one isolated chamber of the nest. This might be an adaptive strategy that facilitates parasitoid dispersal, provides protection to parasitoids, and reduces the risk of parasitism to host colony. An abnormally rounded head capsule and remarkably short mandibles are characteristics of a parasitized soldier. The older larval fly stages were found only in major soldiers. We suggest that parasitization may first start in fourth or even earlier larval termite instars. The fly larva develops in the termite soldier's head capsule and pupates inside the host's body.

Cape-ivy (Delairea odorata Lamaire) is an ornamental vine that has escaped into natural areas in many countries and become a serious pest. It is native to the eastern part of South Africa, and surveys there located several potential biological control agents for this weed. One of these is Parafreutreta regalis Munro, a tephritid fly that causes large galls to form on the stems of the vine. In a collaborative effort, we began to evaluate, in both California and South Africa, the host range of this fly. Between the two locations, we tested 93 plant species and 2 varieties of Cape-ivy to see if, after being exposed to four pairs of flies for a week, any galls would develop on them. No galls were formed on any of the test species, although an average of six galls developed on each of the Cape-ivy controls. We also tested to see whether P. regalis showed any preference for either of the two varieties of Cape-ivy. There was no significant difference between the numbers of galls forming on the stipulate or astipulate varieties. Our tests indicate that this fly is essentially monospecific. Earlier research had shown that P. regalis galls cause a significant reduction in the height and nongall biomass of Cape-ivy. A petition has been submitted to initiate the process of obtaining permission to release P. regalis in California to control the Cape-ivy infestations there.

Fluctuating asymmetry (FA) represents small, random variations from the symmetric bilateral pattern, and it is a frequently used measurement of plant and animal stresses. Some studies have shown a relationship between FA and herbivory, suggesting that FA might be a reliable indicator of plant quality and plant susceptibility to herbivore attack. In this study, we investigated the relationship between leaf FA of Coccoloba cereifera Schwacke (Polygonaceae) and the pattern of attack by the scale insect Abgrallaspis cyanophylly Signoret (Hemiptera: Diaspididae). Thirty individuals of C. cereifera were marked and followed during 2007 in southeastern Brazil, and all leaves of three shoots per plant were sampled, numbered, and categorized as young, mature, or senescent. We measured right and left widths of all leaves after digitizing the images to determine levels of FA for each leaf sampled per plant. Individuals of A. cyanophylli were counted using a stereoscope in the laboratory to determine infestation levels. Leaves of C. cereifera exhibited true patterns of FA, as shown by the normal distribution of asymmetry values. We observed high variation in attack rates by A. cyanophylly among C. cereifera individuals, with 43.3% of plants with no insects, whereas others exhibited up to 23,000 insects. No statistically significant relationship was observed between variation in FA and variation in A. cyanophylli among plants. These results suggest that FA cannot be used as an indicator of plant quality and susceptibility to herbivore attack but suggest that herbivores themselves might act as plant stressors.

Although soybean aphid (Aphis glycines) resistance is commercially available in the form of the Rag1 gene, the mechanism of this resistance is not fully understood. Amino acids are a limiting factor for aphid growth, and there is evidence that plant amino acid composition is related to aphid resistance. Antibiotic resistance like that conferred by Rag1 could be associated in part with both protein and nonprotein free amino acids reducing survival, growth, and fecundity of the target pest. We posed two hypotheses: (1) A. glycines resistance is related to host quality in terms of free amino acids composition in the leaf, and (2) aphids may enhance host quality by inducing changes in the free amino acids composition. To test these hypotheses we conducted a field experiment using a split plot design, with soybean lines (a susceptible line and a related line carrying Rag1) as whole plots and aphid density as subplots (insecticide treated or left exposed to natural infestations). We analyzed free amino acids in leaves at three soybean developmental stages in all subplots. We observed significant whole and subplot effects on the concentration of a subset of amino acids tested. Susceptible and resistant plants had constitutive (whole-plot) differences in amino acids composition in all developmental stages analyzed. In addition, aphid-induced (subplot) responses of the plant to aphid infestation were found. We propose that the reduced nutritional quality of the resistant line and its reduced susceptibility to aphid-induced changes may contribute to aphid resistance conferred by Rag1.

Cactophilic Drosophila flies are excellent models to study adaptation to a relatively narrow spectrum of potential host plants and host-driven evolutionary diversification. Previous studies suggested a complex genetic architecture of wing and male genital morphology in phylogenetically basal species of the D. buzzatii cluster. In this work, we investigate the effect of experimental hybridization and host plant shifts on male genital and wing morphology in D. gouveai Tidon-Sklorz and Sene and D. antonietae Tidon-Sklorz and Sene, a pair of more recently derived species. We explicitly tested the hypotheses that wing and male genital morphology in interspecific hybrids depend on the host plant in which flies were grown. Our study shows that cactus hosts exert a strong effect on genital and wing morphology and that hybrids can be clearly differentiated on the basis of wing and genital morphology from both parental species. However, the extent of morphological differentiation between hybrids and pure species as well as plasticity patterns varied across organs, suggesting a complex genetic architecture for the studied traits.

Chemical communication by many insect species involves complex signals of both insect and plant origin. Much attention has been focused on the behavioral activities of these components but less on their sources of variation, despite implications for evolutionary theory and pest management. We studied variation in chemical signaling at host, tree-within-host, and beetle-on-tree scales using tunneling male pine engravers [Ips pini (Say)] on jack, Pinus banksiana Lamb, red, P. resinosa Aiton, and white, P. strobus L. pines. Pine engravers are distributed transcontinentally, and stereoisomeric ratios of their principal pheromone component ipsdienol varies regionally. Linear mixed-effects models were used to examine variation in monoterpene and pheromone volatile profiles, determined by gas chromatography. Phloem from white pine had the greatest concentration of monoterpenes, although insects tunneling in white pine produced the smallest ratios of monoterpenes to pheromones (1:2) in their volatile plumes relative to jack and red pine (1:1). Beetle-to-beetle variation in plume composition was ≈2–9 times greater than the inter-tree variation within a tree species. The stereoisomeric ratio of ipsdienol was highly consistent within the pheromone component of the plume. The little variation present existed almost entirely at the level of the insects. Within the pheromone component of the plume in a given host species, there was up to 13 times more beetle-to-beetle than tree-to-tree variation. This magnitude was almost double the magnitudes of the ratios among components within the entire plumes. Implications to the behavioral ecology of bark beetle communication, such as potential strategies of cheating and predator avoidance, are discussed.

Myzus persicae and Bemisia tabaci are serious pests of tobacco and can occur simultaneously on the same plant. We found that tobacco plants infested by whiteflies had fewer aphids than those without whiteflies. To determine whether B. tabaci feeding could induce plant defense against aphids locally and systemically, we determined the effects of B. tabaci on several biological parameters of M. persicae on tobacco. Infestation of B. tabaci nymphs reduced survival rates of M. persicae by 30.0%. In three generations, M. persicae populations increased 1,091-fold on uninfested plants compared with 222-fold on the plants with whiteflies. On the upper leaves with systemic damage but uninfested B. tabaci, the survival rate of aphids was 9.3-fold lower than that on plants that were never been infested by whitefly. Survival rates of M. persicae on leaves with whiteflies present or with whiteflies removed were also lower than those on uninfested leaves. Fecundity of M. persicae was not different on leaves with whiteflies, with whiteflies removed or uninfested leaves; however, fecundity on leaves with systemic damage was lower than on uninfested leaves. Growth rates of M. persicae on the leaves with whiteflies, or with whiteflies removed, were higher than on uninfested leaves, whereas it was lower on systemically damaged leaves than on uninfested leaves. The development of M. persicae was ≈1 d longer on systemic leaves with whiteflies than on uninfested leaves. These results indicate that feeding of B. tabaci induced a defense in tobacco plants against M. persicae, both locally and systemically, although other mechanisms may also be involved.

Because mating may be costly, sexually active males or females are predicted to be in relatively good physiological condition and may preferentially direct their mating behavior toward relatively high-quality mates. We tested this hypothesis in Japanese beetles (Popillia japonica Newman), a pest species in which males and females may be either isolated or in aggregations while feeding on host plants. We examined male size and lipid content and female size and egg load with respect to both their pairing status and whether they were isolated or in aggregations. Males that were paired had the highest lipid levels, and single, isolated males had the lowest. Paired females had the highest egg loads and single, isolated females had the lowest. Neither male nor female size was related to pairing status. Females captured during the times of relatively high pairing frequency (i.e., morning and evening) had higher egg loads than females captured at times of lower pairing frequency (i.e., afternoon). These results suggest that mating and aggregative behaviors in Japanese beetles are dependent on the physiological status of males and the reproductive condition of females.

Hylobius warreni Wood, also known as the Warren root collar weevil, is a flightless insect that feeds on conifers throughout the boreal forests of Canada. Mature trees typically can withstand feeding, but larval feeding around the root collar may cause mortality to young trees. Recently, a large outbreak of mountain pine beetle (Dendroctonus ponderosae Hopkins) has killed a high proportion of mature lodgepole pine (Pinus contorta Douglas variety latifolia) across British Columbia, Canada. This raises concerns that adult weevils may migrate from mature forests with reduced host pools into adjacent young forests that had been salvaged and replanted. To study movement of these walking weevils in different habitat types, we constructed three research plots consisting of various combinations of live-, dead-, and mixed (i.e., live and dead)-tree habitats. We observed dispersal patterns of individually labeled insects using a novel insect trap attached to the base of trees. Approximately 35% of insects were recaptured over 1 mo. Weevils were least likely to be recaptured proximate to the release location when released in a habitat with dead trees. Movement rates therein were almost double the rates of insects moving through live- or mixed-tree habitats. Our findings support the hypothesis that H. warreni may disperse out of habitats with dead trees into areas with higher proportions of green trees. Our findings are discussed in the context of habitat discrimination and potential increases in herbivory by H. warreni in western Canada given salvage harvesting activities after outbreaks of mountain pine beetle.

Several Heliconius L. butterflies species form nocturnal aggregations in sites with a particular architecture. Roosts are usually formed under relatively dense vegetation mats where dry vines or branches provide a perch for the night. These sites may last for months. To understand the importance of factors related to the expression of Heliconius roosting, data on light, temperature, relative humidity, wind, and use of wing color cues were recorded at H. erato and H. sara roost sites in Costa Rica and Panama in 2008 and 2009. The results show that roost sites offer reduced light conditions at dusk, provide a drier environment compared with its vicinity, and offer protection from wind and rain. Moreover, individuals use wing color recognition under reduced light conditions at dusk to successfully assemble aggregations. These findings provide key information for future experiments to study the use of landmarks, hygrosensitivity, and dim-light eye adaptations in Heliconius navigation to find roost sites.

Most whitefly parasitoids kill whiteflies in one of two ways, by piercing the whitefly body with the ovipositor and laying an egg or by piercing the body and feeding on host fluids. The effects of food deprivation on host-feeding and parasitizing capacity of the whitefly parasitoids Eretmocerus melanoscutus and Encarsia formosa (Hymenoptera: Aphelinidae) were determined in this study. We investigated the effects of various food-deprivation durations (0, 3, 6, 10, and 24 h, and 20% honey solution offered) before being released on the host mortality and parasitism by these species, using fourth-instar Bemisia tabaci (Homoptera: Aleyrodidae) nymphs as test hosts. Er. melanoscutus that were food deprived for 6 h fed on more hosts than those that were food deprived for 0 and 10 h and those that were fed only on honey solution. En. formosa was less sensitive to food deprivation, there being no significant changes in host feeding and parasitism. These species' differences were further confirmed by using third instars of B. tabaci, and both parasitoid species that were food deprived for 6 h fed on more hosts and parasitized similar or more hosts than those that were not food deprived. We also confirmed that Er. melanoscutus that were food deprived for 6 h killed significantly more whiteflies by host feeding and parasitism combined than the nonfood-deprived Er. melanoscutus. However, there were no significant differences in longevity between food-deprived and nonfood-deprived parasitoids of either species. We concluded that the effectiveness of Er. melanoscutus to biological control whitefly nymphs could be improved by starving them for 6 h prior to release.

Movement behavior determines the success or failure of insects in finding important resources such as food, mates, reproductive sites, and shelter. We examined the response of female red flour beetles (Tribolium castaneum Herbst; Coleoptera; Tenebrionidae) to habitat cues by quantifying the number of individuals that located a patch (either with or without flour) in response to the distance released from the patch, air movement over the arena, and food-deprivation status. We also investigated how patch characteristics, such as resource amount and presence of cover, influenced time taken to find a flour patch, the frequency of entering or leaving, and residence time within the patch. Although the proportion of beetles successfully locating the patch decreased as a function of release distance, the probability that beetles reached the patch was ultimately unaffected by whether flour was present or not, suggesting that search behavior in red flour beetles may exhibit a simple distance-decay function. Significantly more beetles reached the patch when they had not been food deprived and air was flowing over the arena, which indicates that walking beetles may orient to airflow, exhibiting anemotaxis. Results of the second experiment showed that, on first encounter, fewer beetles entered patches with a greater amount of flour; but once they had entered, they left them less frequently than patches with less resource. Beetles entered covered patches more quickly than uncovered patches irrespective of resource amount, which indicates that shelter is perhaps more important to red flour beetles than resource levels in determining whether to enter patches.

The lesser grain borer, Rhyzopertha dominica (F.) (Coleoptera: Bostrichidae), a serious pest of stored cereal grains, is widely distributed and has been collected in different habitats in North America, such as those from agricultural and nonagricultural settings. Our objective was to study the dispersal distances and direction of dispersal by R. dominica after external marking using fluorescent powder, releasing marked beetles, and recapturing adults using pheromone traps in distinctively different ecological habitats, wooded sites and open grasslands, for 2 consecutive yr. The recapture rate of marked beetles ranged from 6 to 26% in both sites and was generally higher in the wooded site than the open field site for both years. There was a significant difference in dispersal distances between wooded and open sites. Mean dispersal distances in the wooded site ranged from 337 to 375 m, whereas in the open site, they varied from 261 to 333 m. Trap captures for both marked and feral beetles were related to the ambient temperature such that increase in trap captures occurred with increasing temperature. Significant differences were observed for directional movement of R. dominica in both sites and indicated that most beetles dispersed in the northwest direction. Correlation analyses showed that the relationship between numbers of marked-released-recaptured beetles significantly decreased with increasing trap distances. Understanding dispersal distances and directions provide insight to flight behavior of R. dominica and to the relationship between ecologically diverse breeding habitats. Knowledge of R. dominica habitat ecology outside of grain storage facilities may be useful in designing suitable management tactics to minimize the onset of infestations in grain storages.

Larra bicolor F. (Hymenoptera; Crabronidae) is a specialist parasitoid of Scapteriscus (Orthoptera; Gryllotalpidae) mole crickets, attacking adults and medium to large nymphs of the hosts. Adult wasps derive energy from plant nectars. In replicated trials in pastures in northern Florida, many more wasps fed on nectar of Spermacoce verticillata F. (Rubiaceae), a non-native plant, than on nectar of the native plants Spermacoce prostrata Aubl. or Spermacoce remota Lamarck. Few of them fed on the native plant Solidago fistulosa Michx. (Asteraceae). About as many fed on the native plant Chamaecrista fasciculata (Michx) Greene as on S. verticillata in the autumn months until the native plant ceased flowering by October. In contrast, S. verticillata continues flowering until the first hard freeze, which typically occurs in December, so overall, it is a more reliable nectar source in northern Florida and may be still more reliable in frost-free areas of southern Florida where it may flower year-round. The number of immature wasps (eggs and larvae) parasitizing mole crickets was positively related to host density but also declined with distance from a plot of S. verticillata out to 200 m, based on samples of pitfall trap—collected mole crickets. The occurrence of parasitized mole crickets at a 200-m distance suggests that female wasps recruited to a plot of S. verticillata forage for hosts out to at least 200 m. This in turn suggests that mole cricket populations might be diminished by planting plots of S. verticillata at least 400 m apart when L. bicolor wasps are present.

A 2-yr study was conducted in South Carolina wheat fields to describe spatial and temporal dynamics of stink bugs sampled with sweep nets. In 2008, the main phytophagous species were Euschistus servus (Say) (35.8, 36.7%), Oebalus pugnax (F.) (35.0, 6.0%), Nezara viridula L., (15.2, 46.3%), and Thyanta custator (F.) (14.0, 10.5%) for adults and nymphs, respectively. In 2009, the main phytophagous species were O. pugnax (39.8, 37.8%), E. servus (38.4, 30.0%), N. viridula (14.6, 29.5%), and T. custator (6.8, 2.8%). χ2 goodness-of-fit tests indicated that all species (both adults and nymphs) had observed distributions that did not match the Poisson distribution. Indices of dispersion (I_D) across sampling dates were significantly >1 for all species and life stages, also suggesting a nonrandom distribution. Slopes of Taylor's power law were significantly greater (P < 0.05) than a value of 1 for only adult O. pugnax and nymph T. custator. Coefficients β of patchiness regressions were significantly >1 in all cases except for E. servus adults and T. custator nymphs. The inverted distance weighted interpolation method showed considerable levels of spatial variability in densities within fields. Sampling along the edge of fields showed a significant distance from field border effect (P < 0.05) on all adults in both years except for N. viridula. High densities in wheat adjacent to a susceptible crop such as corn suggests that localized control methods in wheat may be effective in mitigation of stink bugs and damage in corn.

Grid sampling (one sample per 0.40 ha) in 12 cotton (Gossypium hirsutum L.) fields for stink bugs and boll injury caused by stink bug feeding was conducted in 2007 and 2008 in South Carolina and Georgia. The main species collected using the beat cloth method were the green stink bug, Acrosternum hilare (Say) (69%); brown stink bug, Euschistus servus (Say) (18%); and the southern green stink bug, Nezara viridula (L.) (14%), respectively. The inverted distance weighted interpolation method and Spatial Analysis by Distance IndicEs analyses showed spatial variability in both boll injury and stink bug densities. Four of five fields with field-average boll injury exceeding 15% had a combination of either soybean or peanut adjacent to the cotton field of interest. The Spatial Analysis by Distance IndicEs index of dispersion for stink bug densities and boll injury averaged over the season indicated significant aggregation at the 5% error rate in only one and four analyses (combinations of fields, species, and life stages) of a total of 54 in 2007 and 2008, respectively. By sampling date, overall indices of dispersion for boll injury data indicated significant aggregation in four of the 63 date-field combinations at the 5% error rate. Across years, overall indices of spatial association between boll injury and stink bug densities were significant in 17 of 69 analyses, with positive associations detected in seven of 12 fields; these data suggest that spatial distribution of stink bugs in cotton fields does not always coincide with boll injury.

Indigenous cover crops have the potential to promote an increase in natural enemies providing fortuitous control of pest species and other ecosystem services. We test this idea in a vineyard in south eastern Australia, where reduced water availability because of drought coupled with increased temperatures has generated interest in sustainable alternatives to the exotic perennial cover crops commonly planted. Three endemic perennial cover crops, comprising the grasses Austrodanthonia richardsonii and Chloris truncata and a mix of two saltbushes (Atriplex semibaccata and Atriplex suberecta) were established as cover crops and compared with introduced oats (Avena sativa). Abundance of a range of predators and parasitoids was higher in vines with native cover crops compared with the oat control. In addition, predation levels of sentinel eggs of a common vineyard pest, light brown apple moth (Epiphyas postvittana), were increased in the native cover crops. However, the native cover crops also increased the abundance of some potential pest species. Native plants therefore have potential to increase abundance of beneficial invertebrates that assist in pest control, but need to be used carefully to ensure that they do not increase local pest problems.

Interactions of a biopesticidal formulation of steam distilled shoot extract of Mexican marigold, Tagetes minuta, and entomopathogenic fungi were evaluated for management of the sugarbeet root maggot, Tetanops myopaeformis (Röder). Shoot extract plus surfactant (E–Z Mulse) (=T. minuta oil) was used in a 65:35 ratio to test the hypothesis that this fungicidal and nematocidal biopesticide causes dose-dependent mortality and developmental arrest of T. myopaeformis but does not interfere with the action of entomopathogenic fungi when applied together. A soil-petri dish bioassay system was developed to test the hypothesis. For diapausing, nonfeeding but active 12-mo-old third-instar larvae, 0.5% T. minuta oil treatment (=0.325% active ingredient [AI]) was sufficient to prevent pupation without mortality, but 0.75% T. minuta oil treatment (=0.458% AI) was lethal for 93% of the test insects. The effect of T. minuta oil on fungal efficacy under simultaneous use was studied using a model system of two entomopathogenic fungi, Beauveria bassiana (Bals.) Vuillemin. TM28 and Metarhizium anisopliae variety anisopliae (Metsch.) Sorokin MA 1200, in a soil-based bioassay with larval sugarbeet root maggots. No adverse effects of T. minuta oil on action of entomopathogenic fungi and no synergy were found; an additive effect of the T. minuta oil and each fungal isolate separately was found.

BioLure, a synthetic food attractant for Mediterranean fruit fly [Ceratitis capitata (Wiedemann) ], is composed of three chemicals (ammonium acetate, trimethylamine hydrochloride, and putrescine). We deployed these components together and in separate MultiLure traps across predominantly native forests, non-native forests, farmlands, orchards, and residential areas on the islands of Hawaii and Maui, to evaluate attraction of C. capitata and nontarget insects. Large numbers (as many as 186 per trap per day) of mainly saprophagous nontarget flies (primarily Drosophilidae, Chloropidae, Lonchaeidae, Neriidae, Otitidae, and Calliphoridae) were attracted to BioLure. Very few predators, parasitoids, or pollinators were attracted. Native species, predominantly drosophilid and calliphorid flies, were attracted in large numbers in endemic forests, but mostly (at least 88%) introduced species were collected in orchards, backyards, and non-native forest. A comparison of attraction to the three separate components versus combined components in traps revealed that ammonium acetate and, to a lesser extent, putrescine are the key components attractive to nontarget species. Omitting the putrescine ingredient from BioLure did not drastically decrease C. capitata catches but reduced nontarget captures by 20%.

The effect of temperature on the developmental time, survival, and reproduction of Rhynchophorus ferrugineus (Olivier) reared on sugarcane was studied at seven constant temperatures (16, 20, 24, 28, 32, 36, and 40°C). The developmental threshold temperatures and effective accumulated temperatures for the whole generation were 17.41°C and 1,590.72 DD, respectively. One generation had the highest survival rate (26.67%) at 28°C. The egg failed to survive at 16 and 40°C. The population trend index (I = 38.22) and net reproductive rate (R_o = 38.3) were highest at 28°C. The net reproductive rate (R_o = 3.36), intrinsic rate of increase (r_m = 0.0028), and finite capacity of increase (λ = 1.0028) were lowest at 20°C. The mean generation time (T_o = 85.82) was shortest at 36°C. The population double time (PDT = 27.08) was shortest at 32°C. Based on these studies, we concluded that the temperatures from 28 to 32°C were the most suitable temperatures for the development of R. ferrugineus.

We investigated effects of temperature, at 70% RH, on the reproductive parameters of the parthenogenetic psocid Lepinotus reticulatus Enderlein (Psocoptera: Trogiidae). The lowest fecundity (21) was at 35°C and the highest (41) at 27.5°C. At 22.5, 25, and 27.5°C, peak oviposition rates (eggs/female/week) occurred in week 3 and were 4.7, 6.6, and 7.8, respectively; also 51, 57, and 62%, respectively, of all eggs were laid in the first 4 wk. At 30, 32.5, and 35°C, peak oviposition rates occurred in week 2 and were 8.2, 9.0, and 7.4, respectively; 80, 85, and 98%, respectively, of all eggs were laid in the first 4 wk. The longest preoviposition period (4.4 d) was at 22.5 and 25°C, and the longest postoviposition period (13.1 d) was at 22.5°C. Oviposition period and longevity decreased with increasing temperature; at 22.5°C, these parameters were 66 and 83 d, respectively, and at 35°C, they were 18 and 24 d, respectively. Mean weekly oviposition rate increased with temperature and was highest at 32.5°C (5.8 eggs/female/week). At 22.5, 25, 27.5, 30, 32.5, and 35°C, it took 29, 20, 12, 11, 8, and 6 wk, respectively, for all females to die. Intrinsic rate of population increase increased with temperature until 32.5°C (0.128) and then declined. We have developed temperature-dependent equations for preoviposition period, postoviposition period, oviposition period, oviposition rate, and longevity. Reproductive parameters affect population dynamics, and information on these parameters can be used in simulation models to predict L. reticulatus population dynamics to aid in developing effective management strategies.

Lesser cornstalk borer, Elasmopalpus lignosellus Zeller (Lepidoptera: Pyralidae), is an important sugarcane pest in southern Florida. Development of immature stages (eggs, larvae, prepupae, and pupae) of lesser cornstalk borer was observed on sugarcane at constant temperatures (13, 15, 18, 21, 24, 27, 30, 33, and 36°C), 65–70% RH, and a photoperiod of 14:10 (L:D) h. Total development (from egg deposition to adult emergence) ranged from 22.8 ± 0.3 d at 33°C to 120.7 ± 2.8 d at 13°C. Lesser cornstalk borer required 543.48 DD to complete development. Developmental time decreased with increase in temperature from 13 to 33°C and increased markedly at 36°C in all immature stages. One linear and six nonlinear models used to model insect development (Briere-1, Briere-2, Logan-6, Lactin, Taylor, and polynomial models) were tested to describe the relationship between temperature and developmental rate (d^-1). Criteria used to select the best model were the greatest r², lowest residual sum of squares (RSS), and Akaike information criterion values. The Briere-1 model fit the data best and provided the best estimates of developmental temperature thresholds for all immature stages on sugarcane. The estimated lower and upper developmental thresholds for total development were 9.3 ± 1.8 and 37.9 ± 0.7°C, respectively. The optimal temperature estimated for the total development was 31.39 ± 0.9°C. Based on these results, we can forecast the different stages of lesser cornstalk borer at different times in sugarcane. This will enable us to choose the best time to control this pest with greater precision.

Ophraella communa (Coleoptera: Chrysomelidae) is a leaf beetle that is unintentionally introduced in China. It is a potential biological control agent against common ragweed, Ambrosia artemisiifolia (Asterales: Asteraceae). The effects of temperature on the development and fecundity of O. communa were studied at eight constant temperature regimens (15, 20, 22, 25, 28, 30, 32, 36°C) in the laboratory. The results showed that the developmental periods for egg, larva, pupa, and entire immature stages decreased in response to the increasing temperature, with the exception of 30°C. The survival rates at different developmental stages were higher at 25 and 28°C than at other temperatures. Ovipositional period and longevity of female shortened with the increasing temperature. The highest fecundity of female was observed to be 2,712.3 eggs/female at 28°C. Life table of O. communa was constructed based on the data at 20–32°C. The innate capacity for increase (r_m), the net reproductive rate (R₀), and the finite rate of increase (λ) reached the maximum at 28°C, with values of 0.247, 1,773.0, and 1.280, respectively. The shortest period of a generation (T) was 24.6 d at 32°C, whereas the longest T value was recorded as 79.3 d at 20°C. These results offer valuable insight on the establishment potential of O. communa in new environments with diverse temperature regimens and on its massrearing techniques in laboratory.

Certain biotypes of the Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae) complex cause extensive damage and are important pests and virus vectors in agricultural crops throughout the world. Among the most invasive and well studied are the B and Q biotypes. Recent reports in Shandong Province, China, have indicated that the Q biotype was introduced there in ≈ 2005, whereas the B biotype has been established there for ∼10 yr. Even so, the present distribution of the two biotypes in Shandong has not been examined. The results of this study showed that the B and Q biotypes are both present in Shandong Province based on bar-coding using a ≈450-base fragment of the mitochondrial cytochrome oxidase I (mtCOI) gene. In addition, a B biotype-specific polymerase chain reaction primer pair that amplifies a ≈300 bp mtCOI fragment was designed and used to examine the biotype composition of B. tabaci in selected crops from six provincial locations, using the general mtCOI primers as an internal positive control for DNA quality. The results of this study indicated that the Q biotype was the predominant B. tabaci colonizing all of the crops in the study sites examined. This suggests that the Q biotype has displaced the B biotype in Shandong Province of China, which until now was the predominant biotype. This is the first report of the displacement of the B by the Q biotype in field grown crops in China, and in a locale where neither the B nor the Q biotype is native. We hypothesize that this phenomenon may have been exacerbated by the widespread use of neonicotinoid insecticides for whitefly control, given the sustained efficacy thus far of neonicotinoids against the B biotype, and their failure at times to effectively control the Q biotype.

The potato tuberworm, Phthorimaea operculella Zeller, is one of the most damaging pests of potatoes worldwide. Although tuberworm was recorded in California as early as 1856, it was first reported in damaging numbers in Oregon and Washington in the early 2000s. The objective of this study was to provide baseline information on the population structure of potato tuberworm in the United States. Potato tuberworm adults were collected from potato fields in the major production regions in the United States. Amplified fragment length polymorphisms (AFLP) were used to determine the genetic population structure of potato tuberworm. We used 219 individuals and 335 polymorphic AFLP bands to infer the geographic population structure of potato tuberworm. Posterior probabilities calculated using the model-based clustering method implemented in STRUCTURE, and Fst values calculated using AFLP-SURV confirmed the existence of two distinct populations in the United States (one mostly associated to the western United States and the other one mostly associated to the eastern United States). This study provides baseline data for the molecular characterization of potato tuberworm populations, which will aid in tracking the origin of future invasions within the United States.

The pink hibiscus mealybug Maconellicoccus hirsutus (Green) is a dangerous pest that damages a wide variety of agricultural, horticultural, and forestry crops. Amplified fragment length polymorphism (AFLP) fingerprints were used to characterize the genetic variation of 11 M. hirsutus populations infesting three plant species in Nayarit, Mexico. Analysis was carried out using four primers combinations, producing 590 polymorphic bands. Cluster analysis, as well as bootstrap dendrogram and nonmetric multidimensional scaling analysis, grouped M. hirsutus populations according to their host plant. The estimated F_ST values indicated a high differentiation in M. hirsutus populations among the three host plant species. These results were also supported by a Bayesian analysis, which indicated a population clustering robustness according to their host plant. Genetic variation among populations is not caused by geographic distances, as shown by a Mantel test.

Use of transgenic maize expressing phytase in seeds as feedstuff can greatly increase phosphate availability to livestock and poultry. Because phosphorus is an essential mineral for all living organisms, growing of phytase transgenic maize may affect the performance of the arthropod community in maize fields. We conducted a preliminary study to assess the potential effects of phytase transgenic maize (BVLA430101) on two herbivore species, Ostrinia furnacalis (Guenée) and Helicoverpa armigera (Hübner), both of which are directly exposed to high concentrations of phytase caused by ingestion of transgenic maize kernels. Our results showed that for both species, survival and duration of the first and second instars and fresh weight of the third instar were not affected when fed transgenic phytase maize kernels compared with those fed nontransformed near isoline kernels. Similarly, there was no statistical difference detected for the same life table parameters when the herbivores were fed artificial diet containing either transgenic phytase maize meal or nontransformed maize meal. In addition, the nutrition utilization of the two species was evaluated with the same diet treatments by comparing the following indices: relative food consumption rate (RCR), relative metabolic rate (RMR), efficiency of approximate digestibility (EAD), efficiency of conversation of ingested food (ECI), and efficiency of conversation of digested food (ECD). No statistical difference was detected for any index of either species between transgenic maize and nontransformed maize treatments. These results provide useful baseline information for further studies to assess the potential effects of phytase transgenic maize on other arthropods in maize fields.