Anoplophora glabripennis (Motschulsky) is an introduced invasive pest with the potential to devastate hardwood forests in North America. Using artificial pupal chambers, we documented the time required by teneral adults at three temperatures (20, 25, and 30°C), 60–80% RH, and a photoperiod of 16:8 (L:D) h to initiate boring after eclosion and subsequently bore completely through a 7-mm (range, 3–11 mm) layer of Norway maple wood (Acer platanoides L.). In total, 218 laboratory-reared pupae from the Chicago, IL, or Inner Mongolia, China, populations were used in the study. Females (1.54 ± 0.03 g) weighed significantly more than males (1.12 ± 0.03 g), but the average weights of the beetles emerging in each temperature did not differ. Adult weight was positively correlated with exit hole diameter (diameter [mm] = 2.2 * weight [g] 7.9). The rate at which beetles bored through the wood (136, 178, and 168 mm³/d at 20, 25 and 30°C, respectively) significantly differed between temperatures but did not differ with beetle weight. Temperature had a significant effect on the time it took adults to initiate boring (7, 5, and 4 d at 20, 25, and 30°C, respectively) and subsequently to complete boring to emerge (5, 4, and 4 d at 20, 25, and 30°C, respectively). This suggests that beetles require more than a week to progress from eclosion to emergence in wood, even at summer temperatures. This information on A. glabripennis basic biology is critical for developing phenology models that are used to time exclusion and eradication methodologies.

In 2004, Staphylinid beetle (Coleoptera) assemblages were studied via pitfall trapping to examine the effects of reforestation in southwestern China forests. Sites included two 100-yr-old mature forest types (hemlock—spruce forest and birch forest), and three 40-yr-old forest types established after harvesting (spruce plantation, larch plantation, and natural broad-leaved forest). Staphylinid species richness was greater in natural broad-leaved forests than those in hemlock—spruce forests and spruce plantations, but no significant difference was found in abundance among the five forest types. Beetle assemblages from young forest stands were significantly different from those in older forest stands, and some environmental characteristics, i.e., elevation, proportion of broad-leaved trees, and coarse woody debris, significantly affected species abundances. Moreover, some staphylinid species predominantly found only in older forest stands indicate that mature forest specialists might be threatened by loss of habitat. So it is necessary to retain adequate patches of older successional stages for conserving these beetle assemblages.

We identified the factors that affect the early colonization of burned stands by adults and the progeny surviving in fire-killed black spruce trees for three cerambycid beetles: Acmaeops proteus proteus (Kirby), Acmaeops pratensis (Laicharting), and Monochamus scutellatus scutellatus (Say) (Coleoptera: Cerambycidae) in the northern Canadian boreal forest. Furthermore, we measured if progeny emerging from burned trees was related to patterns of adults captured in traps the same year as the fire. Fire severity at the stand and landscape scales were the most important predictors for colonizing adults. Except for A. pratensis, thick-barked and lightly burned trees positively influenced the occurrence of surviving progeny at the tree level. Last-instar larvae of A. pratensis emerged from burned trees more often in severely burned landscapes. This may result from biotic interactions with intraguild species or predators. With the exception of A. pratensis, variables affecting the postfire abundance and occurrence pattern of adults were strikingly different from progeny emerging after fire. Progeny emerging from burned trees was almost exclusively related to tree- or stand level characteristics, whereas colonizing adults were correlated with variables measured at various spatial scales, and most often at the landscape scale. Moreover, A. proteus proteus and M. scutellatus scutellatus adults were more common in severely burned landscapes, although their progeny emerged more often in lightly or moderately burned trees. Host selection behavior within stands (e.g., host acceptance) by colonizing adults or host suitability for the larvae might have caused this discrepancy.

Arthropod communities in an array of temperate ecosystems follow similar phenological patterns of distinct compositional turnovers during the course of a season. The arthropod community inhabiting leaf ties is no exception. Many caterpillars build leaf ties, shelters between overlapping leaves attached together with silk, which are colonized secondarily by a variety of arthropods. We created experimental leaf ties by clipping overlapping leaves together with metal clips. We censused the arthropod community within experimental ties on two host plants, American beech (Fagus grandifolia Ehrhart), and white oak (Quercus alba L.), weekly for 10 wk during the summer of 2009. Diversity measures for leaf-tying caterpillars and the entire arthropod community within ties varied little between tree species and sampling periods, but caterpillar and arthropod density per tie was significantly higher on white oak than beech and abundance increased on both tree species as the season progressed. The composition (i.e., species presence and abundance) of the leaf-tying caterpillar community and the arthropod community as a whole differed between host-tree species and sampling periods. Although the arthropod communities on American beech and white oak differed, they showed similar patterns of compositional turnover, with distinct communities in early and late summer and a transitional community midsummer.

Competition has been recognized as a major organizing process in ant communities, with ant communities frequently forming spatial mosaics of dominant species associated with subdominants. Often, species exhibit tradeoffs in their ability to discover versus dominate resources, suggesting a mechanism for coexistence. Here we describe spatial patterns of dominant ants in two sites within a coffee plantation. Ants were sampled for three consecutive years by using tuna baits set on a grid on the ground and on coffee bushes. In addition, so as to determine which species discovered baits first and which species dominated baits, a separate experiment was set up where baits were observed every minute for 2 hr. The relative abundance of species followed a power law, with coefficients of determination ranging from 92 to 97% explanation. At site I the terrestrial community is dominated by two species, Pheidole synanthropica Longino and Pheidole protensa Wilson, whereas at site II the community exhibits codominance of four species: P. synanthropica, P. protensa, Solenopsis geminata F., and Pheidole 1 group. The spatial pattern formed by these species is distinct for each of the sites, both in terms of generalized appearance and dynamic stability. The terrestrial foraging ants at site I do not maintain a fixed mosaic over time. In contrast, at site II ants maintain a fixed mosaic. The arboreally foraging ants reflect, to some extent, the pattern of the terrestrial foragers. A possible interpretation of these results is that dominant ants at site I contain competitive intransitivities that generate a changing mosaic, whereas dominant ants in site II are organized in a competitive hierarchy that generates a fixed mosaic.

The stable fly, Stomoxys calcitrans (L.), is a cosmopolitan species of blood-feeding Muscidae and an important pest of cattle. Although the cattle industry is the largest commodity in Montana, no research has been conducted on the abundance, distribution, or impact of stable flies in the state. Observations of stable flies attacking West Nile virus (family Flaviviridae, genus Flavivirus, WNV) -infected pelicans on a refuge in close proximity to pastured and confined cattle provided an opportunity to describe stable fly phenology in a mixed agricultural-wildlife ecosystem. Coroplast cards used to monitor and compare adult populations in three habitats (peninsula, pasture, confinement lot) located within 1.5–4.5 km of each other revealed that temporal dynamics differed by site. Adult abundance was generally lowest at the confinement lot, the only location where larval development was identified. Stable flies were collected on all traps placed in pasture, with traps adjacent to pastured cattle consistently collecting the most. Adults also were collected on the peninsula supporting the pelicans' nesting site, but whether the potential hosts or physical landscape served as an attractant is unclear. At all three sites, data indicated that overwintering was not successful and that a transition occurred from early season immigrating adults that used suitable local larval development substrates to subsequent autochthonous populations.

Understanding seasonal changes in invertebrate populations is important for understanding ecosystem processes and for conservation of invertebrate communities. Few studies have investigated variation in seasonal responses of multiorder and multispecies invertebrate assemblages. To determine whether temporal patterns in invertebrate assemblages and taxa vary between locations and vegetation age since burning, patterns of invertebrate occurrence were investigated monthly for 12 mo in cool temperate buttongrass moorlands at two locations (lowland and montane) containing paired plots with different fire history (young and old regrowth). For both locations and fire-ages, invertebrate taxon richness and abundance were generally higher during the warmer months than during the winter months. At the lowland location, foliage dwelling invertebrates were caught in greater numbers during winter than during summer owing to large numbers of Collembola. Each season had a distinct invertebrate assemblage. The invertebrate assemblages did not differ between young and old regrowth. The shifts in composition of monthly invertebrate assemblages between winter and summer differed between locations with assemblages in cooler months more dissimilar from warmer months at the montane location than the lowland location. Most taxa common to both locations had similar patterns of monthly occurrence but some taxa showed markedly different patterns. Mid- to late summer is the optimum time to conduct short-term surveys in buttongrass moorland to maximize species richness and abundance but short-term studies will miss significant components of the invertebrate community.

The impact of symbionts on their hosts depends on their infection density. In the current study, we investigated the effects of host plant and insecticide resistance on the relative amount of symbionts Portiera, Hamiltonella, Rickettsia, and Cardinium in the whitefly Bemisia tabaci (Gennadius) B biotype. The relative amount of symbionts in three host plant-adapted subpopulations (cucumber, Cucumis sativus L.; cabbage, Brassica oleracea L.; and cotton, Gossypium herbaceum L.) with the same genetic background and insecticide (thiamethoxam)-resistant and -susceptible subpopulations with the same genetic background were measured by quantitative polymerase chain reaction. The results showed that the cucumber population harbored more Portiera than the cabbage and cotton populations, the cabbage population harbored more Hamiltonella than the cucumber population, Hamiltonella amount did not statistically differ between the cotton and cucumber or the cotton and cabbage populations, and the cabbage population harbored more Rickettsia and Cardinium than the cucumber and cotton populations. In addition, the thiamethoxam-susceptible population harbored more Portiera and Hamiltonella than the thiamethoxam-resistant population, whereas the thiamethoxam-resistant population harbored more Rickettsia than the thiamethoxam-susceptible population. These results indicated that relative amounts of symbionts were affected significantly by host plant-adaption and insecticide resistance, and the response to host plant and insecticide differed among the symbionts.

We examined the nematode fauna associated with a species of bark beetle, Dryocoetes uniseriatus Eggers, as part of a biodiversity survey of forest beetle-associated nematodes. Collections were made in a pine stand at an experimental forest station in Ibaraki, Japan, from April to July of 2011; we examined the nematode association in 273 insects collected during this time. In total, 68% of the insects were associated with at least one species of nematode. Six species of nematodes, including two phoretic microbe feeders (Bursaphelenchus rainulfi Braasch & Burgermeister and Micoletzkya sp.), one insect parasite and nematode predator (Devibursaphelenchus cf. eproctatus), one insect parasite (Contortyhnchus sp.), one insect parasite and potential microbe feeder (unidentified rhabditid parasite), and one potential insect parasite and fungal feeder (B. sinensis) were recovered from the beetles. D. cf. eproctatus was enclosed in nematangia on the backsides of the elytra, B. rainulfi was isolated from the backsides of the elytra or enclosed in nematangia, Micoletzkya sp. was isolated from under the elytra, Contortylenchus sp. and a rhabditid parasite parasitized the body cavity, and B. sinensis was found in the digestive tract of the insect. The association patterns of the nematode species varied seasonally, although definitive interactions among species (e.g., segregation, competition) were not observed.

In recent years, the soybean aphid, Aphis glycines Matsumura, has become the most important exotic pest of soybean, Glycine max (L.) Merrill, in North America. Given the significant yield losses that are reported, considerable effort has been expended to characterize the natural enemy community associated with this pest. Several indigenous and naturalized predators have been identified as potential biological control agents, and these include carabid beetles, an abundant and important family of aphid predators. The objectives of this study were to assess the incidence of field predation by Pterostichus melanarius (Illiger), the most common carabid species in Québec soybeans, using molecular gut-content analysis, and to quantify its impact on A. glycines populations through laboratory and field cage experiments. Throughout the growing season between 16.8% (during low aphid density) and 33.7% (at times of high aphid density) of P. melanarius tested positive for aphid DNA. Furthermore, although laboratory feeding trials confirmed that P. melanarius prey on A. glycines, short-term field cage experiments failed to demonstrate a significant reduction of A. glycines populations by carabid beetles. These results suggest a relatively weak interaction between P. melanarius and A. glycines when pest densities are high, but the high predation rate when aphid densities are particularly low suggests these natural enemies may function as important early-season predators.

Green lacewings are generalist predators whose conservation is important for pest control in olive orchards ( Olea europaea L. ) Sustainable farming practices, as opposed to conventional management techniques, are believed to foster the presence of natural enemies. This study therefore aims to analyze the effect of 1) herbicidal weed cover removal and insecticide applications, and 2) the general management systems used in the olive orchards of southern Spain on chrysopid assemblages and abundance. Green lacewing adults and larvae were collected from olive orchards under conventional, integrated, and organic management systems. In addition, chemical analyses of residues were carried out to determine the presence of insecticidal and herbicidal residues. Eight adult species and three genera of larvae were identified. No rare species were captured from the most intensively farmed orchard, which therefore recorded the most limited chrysopid diversity with a very marked dominance of Chrysoperla carnea s.l. No effect of dimethoate treatments on Chrysoperla larvae or C. carneas.l. adults was observed. However, the presence of insecticide residues was associated with the depletion of Dichochrysa larvae. The absence of herbicide treatments favored C. carnea s.l. adult presence on olive trees while larval abundance decreased. Dichochrysa larvae were more abundant when weed cover received no treatment. In relation to the management systems studied, no difference in Chrysoperla larval abundance was observed between conventional and organic orchards. However, Dichochrysa larvae were more abundant in orchards under organic management.

Habrobracon gelechiae Ashmead (Hymenoptera: Braconidae) was studied as a parasitoid of the obliquebanded leafroller, Choristoneura rosaceana (Harris) (Lepidoptera: Tortricidae) in California pistachio (Pistacia vera L.) orchards. Ovipositional behavior, adult longevity and fecundity, and the effects of temperature on developmental time and survival were determined. Habrobracon gelechiae develops as a gregarious, ectoparasitic idiobiont on late-instar C. rosaceana larvae. At 25°C, adult female wasps survived longer when provided honey and water (35.4 ± 4.9 d) or honey, water, and host larvae (34.4 ± 2.4 d) than when provided water (8.9 ± 1.1 d) or no food (5.9 ± 0.8 d). Over the adult lifespan, females parasitized 20.6 ± 2.1 hosts and deposited 228.8 ± 24.6 eggs. The intrinsic rate of increase was 0.24, the mean generation time was 18.15 d, and the double time 2.88 d. At constant temperatures, H. gelechiae successfully developed (egg to adult) from 15 to 35°C. The developmental rate was fit to a nonlinear model, providing estimates of the parasitoid's lower (10.5°C), upper (36.0°C), and optimal (33.3°C) development temperatures. Based on a linear model, 155 degree days were estimated for egg to adult eclosion. Temperature-dependent nonlinear model of survival showed similar shape with the model of development rate. The wasp developed under two diurnal temperature regimes, with 31.0 ± 13.3% survival at low (4–15°C) and 63.0 ± 11.4% survival at high (15–35°C) temperature regimes. The results are discussed with respect to H. gelechiae potential as a parasitoid of C. rosaceana in California's San Joaquin Valley.

Classical biological control against the alfalfa weevil, Hypera postica (Gyllenhal), a destructive pest of alfalfa (Medicago sativa L.), has resulted in the establishment of nine parasitoid species in the United States. Despite widespread redistribution of a number of species, there remains little postrelease data on their establishment and potential effectiveness in many regions. I surveyed parasitoids associated with alfalfa weevil larvae across 30 or more sites in eastern Montana and western North Dakota over 2 yr. Replicate sites were sampled in two habitat types that differ in their physical characteristics, flood-irrigated and dryland alfalfa fields. Irrigated systems are more productive but also more intensively disturbed habitats because of increased harvest frequency and repeated flooding. Given evidence that both habitat disturbance and herbivore density, which often increases with productivity, can influence parasitoid dynamics, I predicted that parasitism levels, the relative importance of different species, or both, would differ across these two system types. Of four larval parasitoid species released previously or recovered in the region, two were found in this study, Bathyplectes curculionis (Thomson) and Oomyzus incertus (Ratzenberg), with average levels of parasitism across habitat types and years of 37.2 and 3.5%, respectively. Parasitism levels differed between habitat types, but the effect was driven by concomitant differences in host densities that were higher in irrigated than dryland fields. Parasitoid responses to host density varied across years and species. B. curculionis exhibited positive density dependence in parasitism across sites in 2009 and negative density dependence in 2010 when host densities were higher regionally. In contrast, O. incertus exhibited positive density dependence in 2010. Our results suggest that these species may be differentially effective at different host densities. Thus, variation in host density could represent an important axis along which parasitoids exhibit spatial complementarity in function.

For animals that lay eggs, a longstanding question is, why do females choose particular oviposition sites? For insects that lay eggs on plants there are three hypotheses: maximizing suitable habitat for juveniles, maximizing female lifespan, and maximizing egg survival. We investigated the function of the oviposition-site choice behavior of a gall midge, the Hessian fly, Mayetiola destructor (Say). In spite of living less than a day and having hundreds of eggs, the ovipositing female is choosy about the placement of eggs. Choosiness makes sense. The tiny gall-making neonate larva has limited movement and strict requirements for colonization. We examined whether offspring benefit from the Hessian fly female's preference for the plant's youngest leaf. To do this we restricted the female's access to the first, second, or third leaf of a seedling (wheat Triticum aestivum L.) plant. Being placed on older leaves did not impact egg survival or larval survival during migration to attack sites at the base of the plant, but did have negative impacts on egg-to-adult survival (reduced by 48%) and reproductive potential (reduced by 30–45%). These negative impacts appear to come from larvae having to search harder to find the limited number of reactive plant cells that can be reprogrammed to form the gall nutritive tissue. We propose that the ability of larvae to find these reactive cells in spite of being placed on an older leaf is important because it creates leeway for female behavior to evolve in the face of other selection pressures, e.g., attack by egg parasitoids.

Spiders are critical predators in agroecosystems. Crop management practices can influence predator density and diversity, which, in turn, can influence pest management strategies. Crop intensification is a sustainable agricultural technique that can enhance crop production although optimizing soil moisture. To date, there is no information on how crop intensification affects natural enemy populations, particularly spiders. This study had two objectives: to characterize the abundance and diversity of spiders in eastern Colorado agroecosystems, and to test the hypothesis that spider diversity and density would be higher in wheat (Triticum aestivum L.) in crop-intensified rotations compared with wheat in conventional rotations. We collected spiders through pitfall, vacuum, and lookdown sampling from 2002 to 2007 to test these objectives. Over 11,000 spiders in 19 families from 119 species were captured from all sampling techniques. Interestingly, the hunting spider guild represented 89% of the spider fauna captured from all sites with the families Gnaphosidae and Lycosidae representing 75% of these spiders. Compared with European agroecosystems, these agroecosystems had greater diversity, which can be beneficial for the biological control of pests. Overall, spider densities were low in these semiarid cropping systems, and crop intensification effects on spider densities were not evident at this scale.

The sampling range of pheromone traps for the navel orangeworm Amyelois transitella (Walker) (Lepidoptera: Pyralidae) and its association with abundance was investigated by examining mutual interference within cross-shaped arrays of nine wing traps baited with virgin females and placed at 400-m intervals in three 256-ha blocks of almonds (Prunus dulcis [Miller] D. A. Webb), and three of pistachios (Pistacia vera L.). The proportions of males captured in the different positions were compared with the mean males for all traps, used as an index for abundance. For means between zero and 50 males per trap per week, the distribution was unequal between trap positions and the greatest proportion of males were captured in the northern-most trap (i.e., the within-row direction). Between 50 and 100 males per trap per week, most males were captured in the western-most traps and fewest in the center, and proportions were equal in other trap positions. Above 100 males per trap per week, the proportion of males captured was more nearly equal for all trap positions. These results demonstrate that the sampling range of pheromone traps for navel orangeworm is density dependent and, at low densities, is >400 m. They also indicate that abundance affects the impact of direction (orientation) of trap interference. At low density, female-strength pheromone traps sample males from beyond the block in which they are placed for orchard blocks of <50 ha.

Oil-coated clear panel traps baited with a host plant-based kairomone lure have successfully been used for monitoring female grape berry moth, Paralobesia viteana (Clemens) (Lepidoptera: Tortricidae), but low capture rates as well as difficulty in servicing these traps makes them unsuitable for commercial use. We compared the performance of different trap designs in a flight tunnel and in a vineyard by using a 7-component synthetic kairomone blend, with a focus on trap visual cues. In flight tunnel experiments, a clear delta trap performed better than other traps. When we tested clear delta, green delta, or clear wing traps baited with a cut grape shoot, >50% of female grape berry moths made complete upwind flights. However, the clear delta trap was the only design that resulted in female moths entering the trap. Similar results were observed when females were tested with different traps (clear delta, green delta, white delta, clear wing, or green wing traps) baited with the kairomone lure. Adding a visual pattern that mimicked grape shoots to the outside surface of the clear delta trap resulted in 66% of the females that made upwind flights entering the trap. However, the positive effect of adding a visual pattern to the trap was not observed in a vineyard setting, where clear delta traps with or without a visual pattern caught similar numbers of females. Still, the number of male and female grape berry moths captured in clear delta traps with or without a visual pattern was not significantly different from the number of male and female grape berry moths captured in panel traps, suggesting that the use of these delta traps could be a less cumbersome alternative to oil-coated panel traps for monitoring female grape berry moth.

Pheromone-based mating disruption is used worldwide for management of the internal fruit feeding codling moth, Cydia pomonella (L.). There has been recent interest in the potential of improving mating disruption of C. pomonella, and potentially other insect species in general, by broadcasting combinations of pheromone and attractive host-plant kairomones. Given that such kairomones are attractive by themselves (often to both sexes), and also enhance male moth response to their pheromone, it is possible that the effects of competitive attraction and potentially other mechanisms of disruption might be increased. Herein, we tested the hypothesis that mating disruption of C. pomonella could be enhanced by co-deploying pheromone with either of two kairomones: (2E, 4Z)-2, 4-decadienoate (pear ester), or (E)-β-farnesene, as compared with various pheromone blend components alone. When deployed individually, each kairomone caused a low level of synthetic lure trap disruption and (E) -β-farnesene also caused disruption of mating as measured by tethering virgin females. However, combined release of either pear ester or (E)-β-farnesene with pheromone within the same dispenser or as a co-deployed dispenser treatment, respectively, did not increase the level of mating disruption as compared with deploying pheromone alone. Disruption efficacy did not decline when reducing the amount of (E,E)-8,10-dodecadien-1-ol (codlemone) in dispensers by fourfold, when combined with pear ester. C. pomonella readily were observed briefly approaching all dispenser types (with and without pheromone) in the field. Exposure of male C. pomonella to pear ester alone in a manner mimicking observed field exposures did not reduce the number of males able to contact a female-mimic pheromone lure in flight tunnel assays. Also, reduction of male moth behavioral response to pheromone was similar after exposure to codlemone alone, and codlemone and pear ester after exposures that mimicked those observed in the field and none of the main treatments tested (pheromone versus pheromone and either kairomone) affected male moth antennal response seconds after exposure as measured by electroantenogram assays. Collectively, our data indicate that disruption of C. pomonella was not improved by co-releasing pheromone with either kairomone tested from point source devices as compared with pheromone alone at the relatively high loading dosages and associated release rates tested.

Experiments were conducted to compare the immature development of Protophormia terraenovae (Robineau-Desvoidy) at fluctuating temperatures of 4–28 and 9–23°C to their mean constant temperature, 16°C. Overall development was fastest at the greater fluctuation and slowest at the constant temperature but showed similar percentages of development time in each stage. The rate summation effect is suspected to have caused this difference in development rate because fluctuations above the mean increase the rate relatively more than temperatures below the mean can lower the rate.

As a key component of ecological risk assessments, nontarget effects of Bacillus thuringiensis (Bt) rice have been tested under laboratory and field conditions for various organisms. A 2-yr field experiment was conducted to observe the nontarget effects of six transgenic rice lines (expressing the Cry1Ab or fused protein of Cry1Ab and Cry1Ac) on four nontarget thrips species including Frankliniella intonsa (Trybom), F. tenuicornis (Uzel), Haplothrips aculeatus (F.), and H. tritici (Kurd), as compared with their rice parental control lines. Two sampling methods including the beat plate and plastic bag method were used to monitor the population densities of the four thrips species for 2 yr. The results showed that the seasonal average densities of four tested thrips species in Bt rice plots were significantly lower than or very similar to those in the non-Bt rice plots depending on rice genotypes, sampling methods, and years. Among all six tested Bt rice lines, transgenic B1 and KMD2 lines suppressed the population of these tested thrips species the most. Our results indicate that the tested Bt rice lines are unlikely to result in high population pressure of thrips species in comparison with non-Bt rice. In some cases, Bt rice lines could significantly suppress thrips populations in the rice ecosystem. In addition, compatibility of Bt rice, with rice host plant resistance to nontarget sucking pests is also discussed within an overall integrated pest management program for rice.