This study investigated relationships between climate and historic spruce beetle, Dendroctonus rufipennis Kirby (Coleoptera: Curculionidae), outbreaks in northern and southeastern Utah and western Colorado between 1905 and 1996. A chronology of outbreak years was constructed from historic records, research papers, newspapers, and other sources of information. Historic climate data for the region included annual and mean monthly temperature and precipitation, in addition to Palmer drought severity index (PDSI) values estimated from tree rings. Classification and regression tree analysis (CART) was used to identify those climate factors most important for predicting historic spruce beetle outbreaks. The factors identified by the best CART model included mean December temperature, mean September temperature 1 yr before outbreak years, the mean estimated PDSI value of the 5-yr period before outbreak years, and mean October precipitation. The resulting model correctly classified nonoutbreak and outbreak years 67 and 70% of the time, respectively.

Interest in the ecological and population genetics of the western corn rootworm, Diabrotica virgifera virgifera LeConte, has grown rapidly in the last few years in North America and Europe. This interest is a result of a number of converging issues related to the increasing difficulty in managing this pest and the need to characterize and understand gene flow in the context of insect resistance management. One of the key components needed for successful population genetics studies is the availability of suitable molecular markers. Using a standard group of microsatellite markers enables researchers from different laboratories to directly compare and share their data, reducing duplication of effort and facilitating collaborative work among laboratories. We screened 22 candidate microsatellite loci against five criteria to create a core set of microsatellite markers for D. v. virgifera population genetics studies. The criteria for inclusion were moderate to high polymorphism, unambiguous readability and repeatability, no evidence of null alleles, apparent selective neutrality, and no linkage between loci. Based on our results, we recommend six microsatellite markers to be included as a core set in future population genetics studies of D. v. virgifera along with any other microsatellite or genetic markers. As more microsatellites are developed, those meeting the criteria can be added to the core set. We encourage other groups of researchers with common interests in a particular insect species to develop their own core sets of markers for population genetics applications.

The soybean aphid, Aphis glycines (Matsumura), is native to eastern Asia and has recently invaded North America, where it is currently the most important insect pest of soybeans. The soybean aphid has spread rapidly within North America, presumably through a combination of active and passive (wind-aided) flight. Here, we studied the active flight potential of A. glycines under a range of environmental conditions using an aphid flight mill. Winged (alate) A. glycines were tested on a specially designed 32-channel, computer-monitored flight mill system. Aphids that were 12–24 h old exhibited the strongest flight behavior, with average flight durations of 3.3–4.1 h, which represented flight distances of 4.6–5.1 km. After the age of 72 h, A. glycines flight performance rapidly declined. The optimum temperature range for flight was 16–28°C, whereas optimum relative humidity was 75%. Our findings show that A. glycines posseses a fairly strong active flight aptitude (ability and inclination) and point to the possibility of flight initiation under a broad range of environmental conditions. These results have the potential to aid forecasting and management protocols for A. glycines at the landscape level.

On Reunion Island, two species of Dacini, Bactrocera cucurbitae (Coquillett) and Dacus ciliatus Loew, infest 16 host plant species belonging to the family Cucurbitaceae from sea level to 1,600 m. These two species represent two primary pests of this plant family on the island. Melon fly, Bactrocera cucurbitae, and Ethiopian fruit fly, D. ciliatus, larval development was studied at four different constant temperatures (15, 20, 25, and 30°C) with three host plants (cucumber, pumpkin, and squash). Adult life histories of these two species were studied at 25°C with the three host plants. The results led to the conclusion that B. cucurbitae had a faster egg incubation time. Its preimaginal instars developed significantly faster than those of D. ciliatus independent of temperature. B. cucurbitae and D. ciliatus had similar mean preoviposition duration and egg hatching success. Fecundity was significantly higher for the melon fly on cucumber and pumpkin and lower on squash. Two distinctly different life- history patterns were evident: (1) later onset of reproduction, longer oviposition time, longer life span, and higher fecundity (B. cucurbitae) and (2) early reproduction, lower oviposition time, shorter life span, and lower fecundity (D. ciliatus). These results are useful for improving laboratory-rearing methods and for building simulation models to predict Dacini population dynamics.

We studied life history responses of larvae of three coccinellid species, Coleomegilla maculata (DeGeer), Hippodamia convergens Guerin-Meneville, and Harmonia axyridis (Pallas), when deprived of food for different periods of time during the fourth stadium. The coccinellid species did not differ in starvation resistance when larvae were starved throughout the stadium; however, for larvae fed only on day 1 of the stadium, H. convergens had the highest starvation resistance, followed by H. axyridis and then C. maculata. Percentage weight loss of larvae was affected by food deprivation period and coccinellid species. Both C. maculata and H. axyridis lost significantly more weight than H. convergens when starved throughout the fourth stadium. When deprived of food for 4 d of the stadium, C. maculata lost a higher percentage of initial body weight than H. axyridis. Percentage weight loss of H. convergens did not differ from that of C. maculata or H. axyridis. The weight of fourth instars and adults declined in an accelerating pattern as food deprivation period increased. However, food deprivation period had no significant effect on pupal development time for any of the three species or on larval development time for C. maculata and H. convergens. The increase in H. axyridis larval development time as a result of an increase in food deprivation period was curvilinear. Based on this laboratory study, it would seem that H. convergens is better able to cope with acute nutritional stress than either C. maculata or H. axyridis.

Important life history parameters of the mealybug, Maconellicoccus hirsutus (Green), were characterized on hibiscus (Hibiscus rosa-sinensis L.) cuttings at six constant temperatures between 15 and 35°C. The development of M. hirsutus was the fastest at 27°C, where the mealybugs completed development in ≈29 d. The lower (T_min) and upper (T_max) developmental thresholds and the optimal developmental temperature (T_opt) for the development of female mealybugs were estimated as 14.5, 35, and 29°C, respectively. The thermal constant (K), which is the number of temperature-day or degree-day units required for development, of the females was 347 DD. The original distribution range prediction (based on T_min = 17.5°C and K = 300 DD) indicated that M. hirsutus could complete at least one generation in all of the continental United States. However, results of this study suggested that the distribution range of M. hirsutus may expand northward because of the lower T_min, and the predicted number of generations in a year may be lower because of the higher K required to complete each generation. The average cumulative survival rate of M. hirsutus at 25 and 27°C was 72%, which was significantly higher than 51 and 62% at 20 and 30°C, respectively. M. hirsutus reproduced sexually, with each mated female producing 260–300 eggs between 20 and 27°C but only ≈100 eggs at 30°C. Female longevity was reduced from 28 d at 20°C to 19–21 d at 25–30°C. At 27°C, the net reproductive rate (R_o) was estimated at 165 ♀/♀, the intrinsic rate of population increase (r_m) was 0.119 (♀/♀/d), the generation time (T_G) was 43 d, and the doubling time (DT) was 5.8 d. The life table statistics suggested that the currently released biological control agents, which have higher r_m than M. hirsutus, will be able to complete more generations than the mealybug within the tested temperature range; thus, they are effective against M. hirsutus.

Although consequences of limited dietary protein and carbohydrate to performance are well studied for terrestrial insect herbivores, the importance of phosphorus (P) remains poorly understood. We examined the significance of dietary P to performance in fifth-instar nymphs of the grasshopper Melanoplus bivittatus fed artificial diets. Consumption, digestion, developmental rate, and growth in response to different levels of P nested within standard-Protein and carbohydrate diets were determined. Developmental rate was slowest on high-P diets; protein:carbohydrate concentration and P in diets affected frass production and consumption. Approximate digestibility and conversion of digested food were primarily influenced by the protein:carbohydrate quality of the diet but not P. Mass gain was marginally lower in the low-Protein:high carbohydrate diet used in this study. At the individual level, other than small effects to developmental rate at high concentrations for M. bivittatus, dietary P otherwise seems to have little effect on nymphal performance. To the degree that it is important, effects of dietary P depend on the concentrations of protein and carbohydrate in the diet.

Development, immature survival, reproduction, and life table parameters of the predatory mite Typhlodromus foenilis Oudemans were evaluated on seven different plant pollens (almond, apple, pear, cherry, apricot, plum, and walnut). Experiments were conducted in environmental chambers at 20 ± 1°C with 65 ± 5% RH and a photoperiod of 16:8 (L:D). T. foenilis successfully completed its development on all pollen diets. Female mean developmental time from egg to adult emergence ranged from 11.3 ± 0.12 to 14.28 ± 0.23 d, whereas that of males was from 10.81 ± 0.17 to 14.17 ± 0.17 d. The average life span of adult females varied from 41.0 ± 1.46 to 65.45 ± 3.89 d, and total fecundity ranged from 11.78 ± 0.65 to 39.09 ± 2.38 eggs/female. The intrinsic rate of increase of T. foenilis was highest on almond pollen (r_m = 0.104/d) and was the shortest on walnut pollen (r_m = 0.055/d). The results show that this predatory mite develops well on all pollens, with almond and apricot pollens being of high nutritional value. This study provides further information for mass rearing of T. foenilis, and these findings are discussed in relevance with the establishment of this species in the field.

Egg and nymphal development were studied under constant temperatures for the newly introduced pest species, Halyomorpha halys (Stål) (Hemiptera: Pentatomidae). Development was assessed at seven constant temperatures (15–35°C). Development to adult was completed at temperatures between 17 and 33°C, with egg hatch also occurring at 15°C. The relationship between temperature and developmental rate was evaluated using three developmental models. Of the models evaluated, the Briere-1 model was the best fit for the empirical data of egg and total development and for providing accurate values for the temperature threshold. Application of the linear degree-day model estimated 537.63 DD are needed for total development (egg to imaginal ecdysis). An additional 147.65 DD are needed for the preoviposition period of the female. Reproductive parameters were evaluated at 25°C and indicate a median number of 28 eggs per egg mass. Oviposition occurred at 4.32-d intervals, and a female can continue to oviposit throughout its lifespan. H. halys is univoltine in New Jersey and Pennsylvania, but if it spreads to warmer climates in the United States, it could have multiple generations per year.

Bark volatiles from green ash Fraxinus pennsylvanica were tested for electrophysiological activity by Agrilus planipennis using gas chromatographic-electroantennographic detection (GC-EAD) and for behavioral activity using baited purple traps in Michigan. GC-EAD analysis of the headspace volatiles of bark tissue samples from 0- and 24-h-old fully girdled (stressed) ash trees showed that the latter had elevated sesquiterpene levels. Six of the elevated compounds consistently elicited antennal responses by both male and female A. planipennis. Five of the antennally active compounds were identified as α-cubebene, α-copaene, 7-epi-sesquithujene, trans-β-caryophyllene, and α-humulene (α-caryophyllene). The sixth EAD-active compound remains unidentified. We monitored capture of adult A. planipennis on traps baited with several combinations of ash tree volatiles. Treatments included two natural oil distillates (Manuka and Phoebe oil) that were found to contain, respectively, high concentrations of four and five of the six antennally active ash bark volatiles. A four-component leaf lure developed by the USDA Forest Service and Canadian Forest Service was also tested. In three separate field studies, Manuka oil–baited traps caught significantly more adult beetles than unbaited traps. Lures designed to release 5, 50, and 500 mg of Manuka oil per day all caught more insects than unbaited traps. In a field test comparing and combining Phoebe oil with Manuka oil, Phoebe oil–baited traps caught significantly more beetles than either Manuka oil–baited traps or unbaited traps. We hypothesize that the improved attractancy of Phoebe oil to A. planipennis over Manuka oil is caused by the presence of the antennally active sesquiterpene, 7-epi-sesquithujene.

The relative attractiveness of synthetic Choristoneura rosaceana (Harris) pheromone consisting of the major compound Z-11-tetradecenyl acetate (Z11–14:OAc), or the major compound plus one, two, or all three of the minor compounds E-11-tetradecenyl acetate (E11–14:OAc), Z-11-tetradecenol (Z11–14:OH), and Z-11-tetradecenal (Z11–14:Ald), in amounts similar to those in the natural pheromone, was compared in a flight tunnel and in apple orchards. In the flight tunnel, there was an increase in the proportion of moths that were activated when E11–14:OAc was combined with the main compound, but no detectible additional increases in response with the addition of Z11–14:OH and Z11–14:Ald. The time required for activation was twice as long when using the major compound than when using the major compound and one or more of the minor compounds. There was a trend of increase in the proportion of males initiating the take-off, lock-on, close-in, and touchdown phases of upwind flight when progressively more complete blends were used. The time required for the initiation of these behavioral phases was statistically similar for each treatment. The proportion of moths landing at the pheromone source was 10 times greater when using the complete blend than when using the main compound alone. Similar results were obtained in apple orchards, where the four-compound blend was 17–55 times more attractive than the main compound. The superior attractiveness of the four-compound pheromone compared with the major compound, or to the major compound plus the minor compound E11–14:OAc, suggests that it would be the most effective synthetic pheromone if competitive attraction were an important mechanism of disruption in this species.

To evaluate the relationship between reproduction and migratory flight, we examined ovaries, tethered flight, and egg laying in the beet armyworm, Spodoptera exigua (Hübner). Ovarian development in female S. exigua was classified into five stages in relation to the postemergence age of the moths. Oviposition peaked at ovarian stages III and IV. Mating accelerated ovarian development in this species, and thus the mated females developed faster than the virgin moths in ovaries. In virgin adults, flight capacity increased from the first day to the third day after emergence and remained at a high level until the moths were 7 d old. In contrast, the mated moths reached the maximum flight capacity in 2 d after emergence and maintained a high level until the age of 7 d. However, mating status could not influence the flight capacity of the beet armyworm, although there were general differences in flight capacity between virgin and mated adults at the same age. Moreover, significant correlations between the number of eggs laid and the flight capacity were not performed by the mated moths. These results showed that mating status and ovarian development did not seem to influence flight capacity in the beet armyworm, which was not in agreement with the definitions of the oogenesis-flight syndrome observed in many other migratory insects.

The results obtained from the spatial analysis of pheromone-baited trap catch data of Lobesia botrana (Denis and Schiffermüller) males are reported. The research was undertaken in the Abruzzo region of central Italy. In the study area, vineyards (of Vitis vinifera L.) are the predominant cultivation, surrounded by hedgerows and small woodlots, and interspersed with cereal crops and olive groves. The main purpose of the study was to investigate the spatio-temporal dynamics of L. botrana, inside and outside vineyards, and to evaluate the effect of the landscape elements on pest distribution. A trend orientation over the experimental area was observed along the direction from northwest to southeast. Correlograms fitted using a spherical model showed in all cases an aggregated distribution and an estimated range having a mean of 174 m in 2005 and 116 m in 2006. Contour maps highlighted that spatial distribution of L. botrana was not limited to vineyards, but its presence is high particularly inside olive groves. The adult distribution on the experimental area changed during the season: hot spots of flight I were positioned inside olive groves; during flights II and III, they were concentrated in vineyards. L. botrana males were also captured in uncultivated fields, but never in high densities. Our results showed that a large proportion of the adult population of L. botrana inhabits areas outside those usually targeted by pest management programs. Thus, in Mediterranean agro-ecosystems, it is highly recommended to consider the whole landscape, with particular attention to olive crops.

We examined the relationship of yellow sticky trap captures of Bemisia tabaci (Gennadius) biotype B parasitoids to the local population of parasitoids as measured by leaf samples of parasitized whiteflies and mass release of parasitoids. Traps were placed in experimental collard and cowpea field plots in Charleston, SC, and in commercial organic fields of spring cantaloupe and watermelon in the Imperial Valley, CA. The exotic parasitoid Eretmocerus emiratus Zolnerowich and Rose was released in Imperial Valley fields to ensure parasitoid populations would be present. Bemisia adults were trapped in the greatest numbers on the upper surface of horizontally oriented sticky traps in melon fields. In contrast, the lower trap surfaces consistently captured more Eretmocerus than upper surfaces. Female parasitoids were trapped in greater numbers than males, especially on the lower trap surfaces. Progeny of released exotic Eretmocerus greatly outnumbered native E. eremicus Rose and Zolnerowich and Encarsia spp. on traps. Throughout the season, the trend of increasing numbers of Eretmocerus on traps parallelled the increase in numbers of whiteflies. Over the season, 23–84% of all B. tabaci fourth instars were visibly parasitized by Eretmocerus. The numbers of Eretmocerus caught by traps in cantaloupe were similar in trend to numbers on leaf samples in melons, but not with those in watermelon, where whitefly populations were lower. Parasitoid numbers were low in collard and cowpea samples, and no trend was observed in numbers of parasitoids captured on traps and numbers on leaves for these two crops. Overall, there were no significant correlations between sticky trap catches of parasitoids and numbers of parasitized whiteflies on leaf samples in any test fields. Nevertheless, sticky traps placed within crops may be useful for observing trends in whitefly parasitoid populations at a particular site and for detecting parasitoids at specific locations.

The Formosan subterranean termite, Coptotermes formosanus Shiraki, is an invasive species that originated in China and has been introduced to Hawaii and the U.S. mainland. Colonies are headed either by a pair of reproductives (simple families) or by varying numbers of inbreeding reproductives (extended families), and therefore have variable degrees of inbreeding. Worker size also varies among colonies of Formosan termites. We tested whether variation in worker size can be explained by the breeding system. Workers were collected from colonies from three geographically separated populations (China, Hawaii, and Louisiana), and body weight and head size were measured. Microsatellite genotyping was used to establish whether colonies were simple or extended families and to determine the heterozygosity of workers and their degree of inbreeding relative to their colony (F_IC, sensitive to the number of reproductives). All Chinese colonies contained multiple inbreeding neotenics. In Hawaii, 37% of the colonies were simple families and 63% were extended families, both having considerable degrees of inbreeding. In Louisiana, 57% of the colonies were simple families, which were mostly headed by unrelated pairs, and 43% were extended families. In simple families, size and body weight of workers were not associated with F_IC or heterozygosity. In extended families of two populations, both size parameters were negatively correlated with F_IC; however, heterozygosity was not associated with worker size in any of the populations. This suggests that the number of reproductives within colonies has a stronger influence on worker size than the individuals’ genetic diversity in Formosan subterranean termite colonies.

This study analyzes the spatio-temporal dispersion patterns of the cabbage maggot (Delia radicum L.) (Diptera: Anthomyiidae) infestation in rutabagas and turnips in Oregon and suggests ways to exploit the spatial and temporal ecology of the cabbage maggot to improve management of the pest. The patchy distribution of cabbage maggots arises from a combination of first-order effects driven by spatial heterogeneity and second-order effects driven by spatial autocorrelation. The intensity of cabbage maggot infestations varied from year to year. Within a given year, damage rates tended to be higher in rutabagas than turnips, in crops planted earlier in the season, and in fields near nurseries and houses. Nonsignificant first-order effects included soil texture, distance from river, proximity to maggot sources (other than cultivated fields), type of vegetation on field borders, field manager, field area, and perimeter. Second-order effects were processes intrinsic to the population and would give rise to patchiness even in a homogeneous environment. For example, adults may be attracted to others of their species or eggs may be deposited in batches. The locations of patches arising from second-order effects cannot be predicted from knowledge of environmental covariates. However, cabbage maggot does not tend to disperse far, and existing patches tend to give rise to other patches nearby at a later time. We found elevated damage rates in spring fields planted near fields that were heavily damaged the previous fall and in fields planted late in the season near fields that had heavy damage early in the season.

Spiders are a megadiverse group that can be useful indicators of the overall species richness and health of biotic communities. The spider diversity in subtropical forests of the Neotropical region are not yet well known, especially in Argentinean subtropical forests where systematic fieldwork has not been done until recently. The Great Chaco is very important as the unique dry subtropical forest of the earth, but it is suffering increasing degradation by the advance of agriculture. Spider communities have been shown to be more directly influenced by vegetation architecture than vegetation species composition. In this study, we aim to assess whether spider diversity and assemblages change in adjacent habitats with different types of vegetation. We compare the diversity and spider assemblages in two different contiguous protected habitats (hygrophilous woodland and savannah parkland) of the Mburucuyá National Park, (Humid Chaco ecoregion). Seasonal samples were obtained using three types of sampling methods: pitfall trapping, beating, and manual litter extraction. The spider assemblages were different in the studied areas, and the abundance, diversity, evenness, and species richness were higher in the hygrophilous woodland than the savannah parkland. These differences in spider diversity and assemblages indicate that both types of habitats are important if the biodiversity is to be conserved in the Chaco ecoregion, where different types of habitat are shown as a patchy distribution.

Species richness and abundance of dung beetles were assessed across a range of bait types that acted as surrogates for the food resources available in Chobe National Park, Botswana. These bait types were comprised of the dung of pig (omnivore), cattle (ruminant herbivore dropping fine-fiberd pads), sheep (pellet-dropping ruminant herbivore), and elephant (monogastric, nonruminant herbivore producing coarse-fibered droppings), and chicken livers (carrion). Species richness was similar between traps baited with pig, cattle, and elephant dung but was relatively lower in those baited with sheep dung and carrion. In traps baited with pig dung, abundance was relatively greater than in all other bait types. A cluster analysis of species abundance distributions for the 30 most abundant species identified four different patterns of bait type association at a 60% level of similarity. All but 1 of the 15 species in cluster A were attracted primarily to the dung of omnivores and pad-dropping ruminant herbivores (pig and cattle). All seven species of cluster B were attracted primarily to coarse-fibered, nonruminant herbivore dung (elephant). All four species of cluster C were primarily carrion and pig dung associated, whereas all four species of cluster D were carrion specialists. In conclusion, the most abundant species were attracted to all bait types, but most species were largely specialized to different dung types or carrion, with dung attracting the majority of the fauna in terms of both species richness and abundance.

The non-native redbay ambrosia beetle, Xyleborus glabratus Eichhoff (Coleoptera: Curculionidae: Scolytinae), has recently emerged as a significant pest of southeastern U.S. coastal forests. Specifically, a fungal symbiont (Raffaelea sp.) of X. glabratus has caused mortality of redbay (Persea borbonia) and sassafras (Sassafras albidum) trees in the region; several other Lauraceae species also seem susceptible. Although the range of X. glabratus continues to expand rapidly, little is known about the species’ biology and behavior. In turn, there has been no broad-scale assessment of the threat it poses to eastern U.S. forests. To provide a basic information framework, we performed analyses exploiting relevant spatio-temporal data available for X. glabratus. First, we mapped the densities of redbay and sassafras from forest inventory data. Second, we used climate matching to delineate potential geographic limits for X. glabratus. Third, we used county infestation data to estimate the rate of spread and modeled spread through time, incorporating host density as a weighting factor. Our results suggest that (1) key areas with high concentrations of redbay have yet to be invaded, but some are immediately threatened; (2) climatic conditions may serve to constrain X. glabratus to the southeastern U.S. coastal region; and (3) if unchecked, X. glabratus may spread throughout the range of redbay in <40 yr. Disruption of anthropogenic, long-distance dispersal could reduce the likelihood of this outcome.

Community assembly and the factors that influence it have long been a topic of interest to ecologists, but theory has yet to produce unequivocal evidence that communities assemble in predictable ways. The goal of this study was to document the relationship between ant communities and environmental variation between four habitat types. To accomplish this, ant communities and 16 environmental variables were sampled across four different habitat types in the Black Belt Prairie and Flatwoods regions in Mississippi. Furthermore, ant species were placed into functional groups for an analysis of the relationship between the assembly of ecological communities and variation in ecosystem function. A total of 20,916 ants representing 68 species was collected across the four habitat types. Nonmetric multidimensional scaling and analysis of covariance analyses both revealed three distinct ant communities, which can be characterized by habitat type: pasture, prairie, and woodland. Principle components analysis (PCA) simplified the 16 environmental variables into four principle components that explained 78% of the variation among sites. Results of multiple regression using the four PCA axes as predictor variables suggest that regional variation in soil structure, land cover type, and the presence of grazing have had major influences on ant community composition. Variation in flora and habitat architecture had smaller but significant effects on ant species diversity and functional group composition. Our results imply that restoration of native ant communities in disturbed habitats must consider how current disturbance regimens likely interact with the presence of Solenopsis to lower ant biodiversity.

To study the oribatid mite community inhabiting microhabitats in the canopy of montane Abies amabilis [(Douglas ex D. Don) Lindl.] and Tsuga heterophylla [(Raf.) Sarg] tree species across five elevational sites, we collected 180 branch tips and 180 foliose/crustose lichen samples over three time periods. Thirty-three species of oribatid mites were identified from the study area. Mite species richness and abundance was significantly affected by microhabitat, and this association was independent of sampling time. At the microhabitat scale, distinct species assemblages were associated with lichen and branch tip habitats, and to a lesser degree, tree species. Conifer specificity was most apparent in the closely related species of Jugatala, where Jugatala tuberosa Ewing was only found on branch tips from A. amabilis and Jugatala sp. was primarily found on branch tips from T. heterophylla. Microhabitat specificity was most pronounced in Dendrozetes sp. where most individuals were found on branch tips and Anachiperia geminus Lindo et al. that occurred primarily on lichens. Principal components analysis of oribatid mite community composition further showed a high degree of association with microhabitat and tree species. Habitat profiles are difficult to discern for many species because tree, microhabitat, and elevation preferences confound distribution patterns. Given the significant tree-microhabitat associations in species composition in this montane canopy study, we suggest that sampling multiple microhabitats across elevations to look for patterns in community structure offers opportunities to explicitly test organizing principles in community ecology.

Blueberry scorch virus, a commercially important Carlavirus in highbush blueberry, Vaccinium corymbosum L., is vectored by aphids (Hemiptera: Aphididae). We surveyed the aphids, primary parasitoids (Hymenoptera: Aphelinidae, Braconidae), and associated secondary parasitoids (Hymenoptera: Charipidae, Megaspilidae, Pteromalidae) on highbush blueberry and other Vaccinium in the Pacific Northwest from 1995 to 2006, with samples concentrated in 2005 and 2006, to lay the groundwork for augmentative biological control. Ericaphis fimbriata (Richards) was the principal aphid. The dominant parasitoid species were Praon unicum Smith, Aphidius n. sp., A. sp., and Aphidius ervi Haliday. Their frequency in relation to the other primary parasitoids varied significantly with geographical area; P. unicum dominated the frequency distribution in southwestern British Columbia, A. n. sp., west of the Cascades, and A. sp. and A. ervi east of the Cascades. Among the secondary parasitoids, pteromalids dominated, and their frequency in relation to the other secondary parasitoids was lowest in southwestern British Columbia. The parasitization rate for P. unicum and A. n. sp. in southwestern British Columbia increased from May or June to a maximum of 0.080 ± 0.024 and 0.090 ± 0.084 (SD), respectively, in late July or early August. P. unicum emerged in the spring 4 wk before A. n. sp. The parasitization rate for P. unicum was lower in conventional than organic fields. Whereas aphid density increased monotonically, P. unicum had two spring peaks. A simulation model showed that these peaks could reflect discrete generations. Releases of insectary-reared P. unicum at 150 or 450 DD above 5.6 °C, summing from 1 January, may effectively augment the natural spring populations by creating overlapping generations.

Habitat manipulation is a branch of conservation biological control in which vegetation complexity and diversity are increased in managed landscapes to provide food and other resources for arthropod natural enemies. This is often achieved by maintaining noncrop plant material such as flowering strips and beetle banks that provide natural enemies with nectar and pollen, alternative prey, shelter from disturbance, and overwintering sites. In most cases, plant material used in habitat manipulation programs is not native to the area in which it is planted. Using native plant species in conservation biological control could serve a dual function of suppressing pest arthropod outbreaks and promoting other valuable ecosystem services associated with native plant communities. We evaluated 10 plant species native to Maryland for their attractiveness to foliar and ground-dwelling natural enemies. Plants that showed particular promise were Monarda punctata, Pycnanthemum tenuifolium, and Eupatorium hyssopifolium, which generally harbored the greatest abundance of foliar predators and parasitoids, although abundance varied over time. Among ground-dwelling natural enemies, total predator and parasitoid abundance differed between plant species, but carabid and spider abundance did not. Matching certain plant species and their allied natural enemies with specific pest complexes may be enhanced by identifying the composition of natural enemy assemblages at different times of year and in both foliar and ground habitat strata.

Studies have suggested that plant-based nutritional resources are important in promoting high densities of omnivorous and invasive ants, but there have been no direct tests of the effects of these resources on colony productivity. We conducted an experiment designed to determine the relative importance of plants and honeydew-producing insects feeding on plants to the growth of colonies of the invasive ant Solenopsis invicta (Buren). We found that colonies of S. invicta grew substantially when they only had access to unlimited insect prey; however, colonies that also had access to plants colonized by honeydew-producing Hemiptera grew significantly and substantially (≈50%) larger. Our experiment also showed that S. invicta was unable to acquire significant nutritional resources directly from the Hemiptera host plant but acquired them indirectly from honeydew. Honeydew alone is unlikely to be sufficient for colony growth, however, and both carbohydrates abundant in plants and proteins abundant in animals are likely to be necessary for optimal growth. Our experiment provides important insight into the effects of a common tritrophic interaction among an invasive mealybug, Antonina graminis (Maskell), an invasive host grass, Cynodon dactylon L. Pers., and S. invicta in the southeastern United States, suggesting that interactions among these species can be important in promoting extremely high population densities of S. invicta.

The hemlock woolly adelgid, Adelges tsugae Annand (Hemiptera: Adelgidae), is causing widespread mortality of eastern hemlock, Tsuga canadensis L. Carrière, in the eastern United States. In western North America, feeding by A. tsugae results in negligible damage to western hemlock, Tsuga heterophylla (Raf.) Sargent. Host tolerance and presence of endemic predators may be contributing to the relatively low levels of injury to T. heterophylla caused by A. tsugae. Field surveys of the predator community associated with A. tsugae infestations on 116 T. heterophylla at 16 sites in Oregon and Washington were conducted every 4–6 wk from March 2005 through November 2006. Fourteen uninfested T. heterophylla were also surveyed across 5 of the 16 sites. Each sample tree was assigned an A. tsugae population score ranging from 0 to 3. Predators collected from A. tsugae–infested T. heterophylla represent 55 species in 14 families, listed in order of abundance: Derodontidae, Chamaemyiidae, Hemerobiidae, Coccinellidae, Cantharidae, Reduviidae, Miridae, Syrphidae, Chrysopidae, Coniopterygidae, Staphylinidae, Anthocoridae, Nabidae, and Raphidiidae. Laricobius nigrinus Fender (Coleoptera: Derodontidae), Leucopis argenticollis Zetterstedt (Diptera: Chamaemyiidae), and Leucopis atrifacies (Aldrich) (Chamaemyiidae) were the most abundant predators; together comprising 59% of predator specimens recovered. Relationships among predators and A. tsugae were determined through community structure analysis. The abundances of Laricobius spp. larvae, L. nigrinus adults, Leucopis spp. larvae, and L. argenticollis adults were found to be positively correlated to A. tsugae population score. Predators were most abundant when the two generations of A. tsugae eggs were present. L. argenticollis and L. atrifacies were reared on A. tsugae in the laboratory, and host records show them to feed exclusively on Adelgidae.

A bacterial formulation containing spores of a Brevibacillus laterosporus strain from Sardinia, known to be toxic by ingestion to the house fly (Musca domestica), was assayed in laboratory, outdoor, and field conditions for the control of immature stages of this pest. In all laboratory assays, the bacterial formulation exhibited toxicity against house fly larvae. A concentration of 1 × 10⁸ spores of B. laterosporus/g of diet caused 100% mortality of house fly immature stages. The same formulation, applied at a concentration of 1 × 10⁸ spores/ml, equivalent to a dose of 2 liters/m², caused a reduction in adult emergence from laboratory and natural breeding substrates (outdoor cage experiments) up to 80.3 and 57.8%, respectively. Similarly, this formulation applied in the cow pen of a diary farm at a dose of 2 liters/m² produced a significant reduction (30%) in immature fly development. Therefore, the use of this bacterial preparation in microbiological control strategies for the integrated pest management of this species is promising.

Five insect biological control agents that attack flower heads of spotted knapweed, Centaurea stoebe L. subsp. micranthos (Gugler) Hayek, became established in western Montana between 1973 and 1992. In a controlled field experiment in 2006, seed-head insects reduced spotted knapweed seed production per seed head by 84.4%. The seed production at two sites in western Montana where these biological control agents were well established was 91.6–93.8% lower in 2004–2005 than 1974–1975, whereas the number of seed heads per square meter was 70.7% lower, and the reproductive potential (seeds/m²) was 95.9–99.0% lower. The average seed bank in 2005 at four sites containing robust spotted knapweed populations was 281 seeds/m² compared with 19 seeds/m² at four sites where knapweed density has declined. Seed bank densities were much higher at sites in central Montana (4,218 seeds/m²), where the insects have been established for a shorter period. Urophora affinis Frauenfeld was the most abundant species at eight study sites, infesting 66.7% of the seed heads, followed by a 47.3% infestation by Larinus minutus Gyllenhal and L. obtusus Gyllenhal. From 1974 to 1985, Urophora spp. apparently reduced the number of seeds per seed head by 34.5–46.9%; the addition of Larinus spp. further reduced seed numbers 84.2–90.5% by 2005. Path analysis indicated that both Larinus spp. and U. affinis contributed significantly to reduction of seed production over the 30-yr period. Spotted knapweed density may not decrease significantly until the seed bank falls below a critical threshold.

Pyrrhalta viburni Paykull, a new landscape pest in the United States, feeds in both the larval and adult stages on foliage of plants in the genus Viburnum. We measured lifetime oviposition capacity of mated and unmated females reared in the laboratory versus field-collected females, as well as ovipositional response to physical characteristics of the host plant. Both mated and unmated females produced eggs, but at different rates. Field-collected females and mated females reared in the laboratory laid similar numbers of egg masses containing similar numbers of eggs, but unmated females laid approximately one half as many eggs, the result primarily of smaller clutch size. Mated females reared in the laboratory had a preovipositional period of 11.4 ± 1.7 versus 29 11.7 d for unmated females, and unmated females lived significantly longer than mated females. The angle and diameter of stems of V. trilobum, a very susceptible host, both greatly influenced oviposition; females laid most eggs on vertically oriented stems, and those of smallest diameter; when these factors were combined, stem diameter predominated. Females also had a very strong geotactic response, preferring to lay eggs on portions of stems toward gravity, even when stems were at fairly shallow angles.

Zoophytophagy is an omnivorous activity that occurs when a primarily carnivorous species feeds on plant material. Plant feeding by beneficial predators may have negative consequences if the plant material has been chemically treated, contains toxins, or was transgenically altered. Although common in predaceous Hemiptera, zoophytophagy has been rarely studied in aphidophagous coccinellids. This study examined the likelihood of feeding on Bt and non-Bt corn seedlings by third- and fourth-instar coccinellid larvae, the regularity of feeding events by fourth instars, and the effect of leaf feeding on development time and adult size. Both third- and fourth-instar Harmonia axyridis Pallas and Coleomegilla maculata DeGeer consume leaf tissue, with fourth instars being significantly more likely to feed on corn seedlings. C. maculata larvae ingested leaf tissue more frequently than H. axyridis. Furthermore, when given access to corn seedlings daily, development time of fourth-instar C. maculata increased after Bt hybrid corn treatments compared with non-Bt corn treatments. Zoophytophagous feeding behavior is thought to sustain predators during times of low prey availability, and leaf tissue feeding by coccinellids has typically been attributed to their need for water. However, in this study, tissue feeding regularly occurred even though coccinellid larvae had constant access to water and a daily ad libitum supply of aphids. We suggest that, in addition to environmental conditions, the physiological state of the zoophytophagous species will influence the probability of plant feeding.

A soil-less bioassay arena to test repellency of wireworms (A. obscurus) to insecticides and carrier solvents is described. The bioassay and variables measured distinguish between shorter-range (contact and/or volatile) and longer-range (volatile) repellency. Wireworm positions are recorded every 3 s for 20 min, and average speed, rate of slowing, and longer- and shorter-range repellent behaviors calculated. Shorter-range repellency is determined with a Wireworm Repellency Score (WRS, range 0–100), calculated before contact and after contact with test chemicals. Of two carrier solvents tested, wireworms were strongly repelled by acetone (WRS = 57) but not by water (WRS = 1) when introduced to the bioassay arenas immediately after chemical inoculation. When bioassay arenas were assembled/sealed 2 min after inoculation, acetone elicited no repellency (WRS = 2). When dissolved in acetone in bioassays assembled with a 2-min delay, imidacloprid, chlorpyrifos, lindane, and tefluthrin elicited slight to moderate repellency at the highest concentrations tested (WRS = 30, 48, 42, and 49, respectively). Both longer- and shorter-range repellency increased over the duration of the observation period for lindane and tefluthrin, and shorter-range repellency also increased over the duration of the observation period for chlorpyrifos. Removal of volatiles in the bioassay arena by vacuum considerably affected wireworm movement in the arena, with the repellency elicited by acetone and lindane being significantly reduced. Clothianidin elicited no longer- or shorter-range repellency.

Mounting evidence suggests that pollinators worldwide are experiencing dramatic population declines, and exposure to pesticides is one of the factors that can account for this. By making use of a database containing more than two decades of honey bee (Apis mellifera) hive poisoning incidents from the United Kingdom (Wildlife Incident Investigation Scheme [WIIS]) and corresponding pesticide use surveys, we attempted to explain honey bee poisoning incidents in the field using models derived from pesticide use information, laboratory-generated bee toxicity data (defined as a hazard ratio; application rate divided by LD₅₀), and physico-chemical properties of the applied pesticides. Logistic regression analyses were used to assess the relationship between honey bee poisoning incidents in the field and these parameters. In analyzing models with multiple dimensions, we selected the best model by the best subset method, an iterative method based on maximum likelihood estimation, and Akaike’s information criterion. Results suggested that the size of the area treated and hazard ratios calculated from application rates and oral or contact toxicity (but the latter especially) can be used to predict the likelihood that honey bee mortality will occur. Model predictions also suggest that some insecticides carry an extreme risk for bees, despite the lack of documented incidents.

Six Alabama Satsuma mandarin orchards (four conventionally sprayed and two unsprayed) were surveyed during 2005 and 2006 to determine the population dynamics of arthropod pests and their natural enemies. Twenty-eight arthropod pest species were encountered; the major foliage pests were citrus whitefly, Dialeurodes citri (Ashmead); purple scale, Lepidosaphes beckii (Newman); Glover scale, L. gloveri (Packard); and citrus red mite, Panonychus citri (McGregor). Two distinct population peaks were recorded for citrus whitefly at most locations. The most important direct sources of citrus whitefly mortality were parasitism by Encarsia lahorensis (Howard) and infection by the pathogenic fungus, Aschersonia aleyrodis Webber. In general, all stages of both scale insects (purple scale and Glover scale) were present in the orchards year-round, indicative of overlapping generations; however, the highest densities were recorded during the early season. Citrus whitefly, purple scale, and Glover scale were more abundant on leaves collected from the interior of the tree canopy than in the exterior canopy. Citrus red mite densities were highest in the spring, with populations declining at the start of the summer, and were more abundant in the exterior canopy than in the interior canopy. The most important natural enemies of citrus red mite were predatory mites belonging to several families, of which Typhlodromalus peregrinus Muma (Phytoseiidae) was the predominant species. Major differences were recorded in the relative abundance of different arthropod pest species in the orchards: citrus whitefly, purple scale, and Glover scale predominated in the unsprayed orchards, whereas citrus red mite infestations were more severe in the sprayed orchards. The results are discussed in relation to the possible effect of orchard management practices on abundance of the major pests.

Different generations of the carob moth, Ectomyelois ceratoniae (Zeller), use different date, Phoenix dactylifera L., fruit stages as they become available during the summer months in southern California. These are the kimri, khalal, and tamar fruit stages. This study was conducted to determine whether carob moth development and fitness were affected by these different fruit stages. Developmental time from neonate larvae to adult, when reared at 31.9°C and 82.1% RH, ranged from 30.5 to 32.3 d for females and 27.1 to 29.5 d for males on the different field-collected fruit stages. Males and females had the highest emergent weight when reared as larvae on kimri fruit and the lowest on tamar fruit. Females laid the most eggs when reared on kimri fruit and the least when reared on tamar fruit. Estimates of population doubling times ranged from 5.4 d on artificial diet (included as a control) to 7.5 d on tamar fruit. This short doubling time shows the ability of carob moth to develop rapidly under optimal conditions. Degree-day (DD) estimates for carob moth development ranged from 636 DD on kimri fruit to 658 DD on tamar fruit, which translate to 32–50 d under field temperatures in the area where dates are grown. Potential implications for field management of E. ceratoniae include improved timing of insecticide treatments to limit population growth early in the season rather than the conventional late season approach.

The abundance of the Colorado potato beetle, Leptinotarsa decemlineata (Say), in organically grown potato did not change significantly in response to increasing rates of dehydrated poultry manure. However, peaks of abundance of larvae were shifted forward in time in response to the high rate of organic fertilizer. Tests using excised foliage showed that the shift was not caused by differential larval mortality or longer developmental times. Time allocation to resting, walking, and feeding by adults was similar regardless of fertilizer rate. Adult foliage consumption was unaffected by organic fertilizer rates in no choice tests and significantly affected in few choice tests. A 22% longer larval development time on plants treated with low fertilizer rate than on plants with high rate was the most significant effect. Even though maximum plant height, canopy, biomass, and yield were significantly smaller in the organic than in conventional plots, the suitability of the plants was not affected except for reduced feeding by summer beetles. Summer adults spent less time feeding and consumed two to five times less foliage on organic potato than on inorganically fertilized and conventionally produced plants. The overall influence of fertilizer on Colorado potato beetle populations was limited and therefore can only play a secondary role in management strategies for organic potato. Avoidance of excessive organic fertilizer that promotes short larval development time and extension of the period over which large Colorado potato beetle larvae are present should be recommended.

Greenbug, Schizaphis graminum (Rondani) (Hemiptera: Aphididae), was first discovered damaging seashore paspalum (Paspalum vaginatum Swartz) turfgrass in November 2003 at Belle Glade, FL. Inquiries to several golf courses with seashore paspalum turf across southern Florida indicated infestation was wide spread by April 2004. Damage symptoms progress from water soaked lesions surrounding feeding sites within 24 h to chlorosis and necrosis of leaf tips within 96 h. Problems caused by greenbug feeding were initially misdiagnosed as fertilizer, disease, other insects, or water management problems because aphids were not previously found on warm season turfgrasses. Greenbug development and fecundity studies were conducted on six seashore paspalum varieties: ‘Aloha,’ ‘SeaDwarf,’ ‘SeaGreen,’ ‘SeaIsle,’ ‘SeaWay,’ and ‘SeaWolf.’ Greenbug did not survive on ‘SeaWolf.’ Development rates (mean ± SEM) ranged from 7.6 ± 0.2 to 8.2 ± 0.2 d on the remaining varieties. Greenbug longevity and fecundity on ‘Aloha’ were significantly less than on the other varieties. The estimated intrinsic rate of natural increase (r_m) for greenbug ranged from 0.24 to 0.26 across tested varieties. Values for net reproductive rate (R_o) ranged from 12.3 on ‘Aloha’ to 40.4 on ‘SeaWay.’ In feeding trials on indicator plants, the Florida isolate of greenbug exhibited a unique biotypic profile most commonly found on noncultivated grass hosts. It was virulent on the wheat variety GRS1201 that is resistant to the principal agricultural biotypes attacking small grains and to all currently available resistant sorghum varieties.

Hairy nightshade, Solanum sarrachoides (Sendtner), is a ubiquitous weed in potato agro-ecosystems and nonagricultural lands of southeastern Idaho and the Pacific Northwest. This weed increases the complexity of the Potato leafroll virus (PLRV) (Luteoviridae: Polervirus)-potato pathosystem by serving as aphid and virus reservoir. Previous field studies showed higher densities of green peach aphid, Myzus persicae (Sulzer), and potato aphid, Macrosiphum euphorbiae (Thomas), the two most important vectors of PLRV, on S. sarrachoides compared with potato plants in the same fields. Some of the S. sarrachoides plants sampled in these surveys tested positive for PLRV. Viral infections can alter the physiology of plant hosts and aphid performance on such plants. To understand better the potential effects of S. sarrachoides on the PLRV-potato-aphid pathosystem, the life histories of M. persicae and M. euphorbiae were compared on virus-free and PLRV-infected S. sarrachoides and potato. Individual nymphs of each aphid species were held in clip cages on plants from each treatment to monitor their development, survival, and reproductive output. Nymphal survival for both aphids across plant species was higher on S. sarrachoides than on potato, and, within plant species, it was higher on PLRV-infected plants than on noninfected plants. With a few exceptions, similar patterns occurred for fecundity, reproductive periods, adult longevity, and intrinsic rate of increase. The enhanced performance of aphids on S. sarrachoides and on PLRV-infected plants could alter the vector population dynamics and thus the PLRV-disease epidemiology in fields infested with this weed.

Atmospheric levels of carbon dioxide (CO₂) have been increasing steadily over the last century. Plants grown under elevated CO₂ experience physiological changes that influence their suitability as food. Previous studies have found increased insect herbivory on plants grown under elevated CO₂. To determine effects of consuming foliage of soybean (Glycine max) grown under elevated CO₂ on adult survivorship and fecundity, Japanese beetles (Popillia japonica Newman) were fed for the duration of their adult lives leaves grown under elevated CO₂ (550 μmol/mol), under ambient atmosphere (370 μmol/mol), or grown under ambient atmosphere but supplemented with a solution of sugars. To determine effects of a diet of foliage grown under elevated ozone (O₃), another anthropogenic gaseous pollutant, beetles in the laboratory were fed soybean leaves grown under elevated CO₂, elevated O₃, or a combination of both elevated gases. Leaf tissue was also analyzed for longevity-enhancing antioxidants, because increases in dietary antioxidants can increase lifespan. Lifespan of Japanese beetles was prolonged by 8–25% when fed foliage developed under elevated CO₂, but consuming foliage that had taken up sugars to approximately the same level as foliage grown under elevated CO₂ had no effect on fecundity or longevity. Females consuming elevated CO₂ foliage laid approximately twice as many eggs as females fed foliage grown under ambient conditions. Consuming foliage grown under elevated O₃ had no effect on fecundity. No significant differences in total antioxidant content of foliage from ambient and elevated CO₂ conditions were detected. Although the precise mechanism is unclear, by altering components of leaf chemistry other than sugar content, elevated CO₂ may increase populations of Japanese beetles and their impact on crop productivity.

Adult activity of native green June beetles, Cotinis nitida L., and invasive Japanese beetles, Popillia japonica Newman, peaked in late July in Kentucky coincident with later stages of veraison in early- and midseason ripening grape (Vitis spp.) cultivars. Most C. nitida feeding aggregations sampled on clusters of early-ripening grapes in the research vineyard also contained Japanese beetles. Assays showed C. nitida generally are unable to bite into intact ripe grape berries, whereas Japanese beetles readily do so. The beetles’ disparate biting ability is likely because of differences in their mandibles, which are sharply pointed and opposable in P. japonica compared with C. nitida mandibles that are bluntly spatulate, do not meet at their tips, and seemingly are only suited for feeding on fruit pulp or other soft food. Japanese beetles were shown to facilitate C. nitida feeding by biting through the skin and providing access to the soft berry pulp. Juice from early- and midseason ripening grape cultivars with relatively high sugar content elicited the greatest feeding by P. japonica. A scenario is suggested wherein Japanese beetles open wound sites and contaminate fruits with yeasts that induce fermentation volatiles that attract C. nitida. Japanese beetles had difficulty biting berries of Sunbelt, a late-ripening cultivar. Phenological resistance, i.e., planting cultivars that ripen after peak flight, could be an effective management strategy. Establishment of P. japonica in grape-growing regions of the southeastern United States will likely elevate the pest status of C. nitida in vineyards.

Popcorn was evaluated in a series of experiments conducted over four growing seasons for its potential as a refuge for European corn borer, Ostrinia nubilalis (Hübner). Objectives of these studies were to determine whether more larvae were produced in popcorn than in field corn and to determine how popcorn influenced female oviposition and larval distribution in neighboring field corn. Two varieties of popcorn (M140, 105d and M3374Y, 118d), one mixture of popcorn (50% 105d and 50% 118d), and field corn (DK580, 108d) were evaluated. Number of egg masses, eggs per egg mass, and larvae were significantly higher in popcorn compared with field corn. Moth oviposition and larval distribution were evaluated using 105d popcorn embedded in several cornfields across Iowa. The row of field corn adjacent to popcorn had significantly more larvae compared with background field corn. In larger field experiments, O. nubilalis larval survival after overwintering was significantly different, with 2.2–18.7 times more O. nubilalis larvae surviving in popcorn than field corn. The potential use of popcorn as an O. nubilalis refuge for genetically engineered corn is considered.