Rabbitbrush, Chrysothamnus Nuttall spp. (Asteraceae), is a common perennial native shrub across the inland western United States. In the Columbia Basin growing district of Washington State, rabbitbrush is often found in close proximity to potatoes and other agronomic crops, but its value as a conservation reservoir and source of parasitoids of merit in agriculture is unknown. Here, we define the aphid parasitoids frequenting rabbitbrush, their aphid host preferences, seasonal occurrence, and linkage or association with other aphids of economic and noneconomic importance. Extensive field collections, lab-holdings, and rearings were used to explore and characterise the fauna. One new species of aphidiine parasitoid is described and illustrated: Praon cowiche Hollingbery and Pike, new species and a key to the parasitoids of rabbitbrush aphids is provided.

Galls of Diplolepis variabilis (Bassett) (Hymenoptera: Cynipidae) on their host plant Rosa woodsii Lindley (Rosaceae) support a diverse community of parasitoid and inquiline wasps that exploit the gall inducer and the gall itself. Here, we studied quantitative variation in local structure of the gall community in the Okanagan Valley of southern British Columbia, Canada, from the United States border north, to test the hypothesis that dispersal limitation would generate a distance decay in gall community similarity. We also explored gall community richness in relation to latitude, as the northern range limit of the gall inducer occurs within our study area. We found that gall communities exhibited strikingly similar composition across the study region, with most of the major inquilines and parasitoids present across the gall's range. However, the increased richness of rare parasitoid taxa near the northern range limits of D. variabilis generated a marginally significant positive relationship between gall community richness and latitude. Overall, our study suggests that dispersal constraints do not influence the composition of the Diplolepis Geoffroy gall community at regional scales, and that gall communities offer useful models for studying the association between community structure and range limits.

Agricultural practices affect the biotic and abiotic conditions that determine food and shelter for carabid beetles (Coleoptera: Carabidae). We hypothesised that carabid communities would respond differently to 18 years of contrasted cropping practices in cereal-based rotations. We measured the effects of tillage (MP: moldboard plough; CP: chisel plough; NT: no-till) and previous crop sequence (cereal monoculture versus cereal–forage/cereal–oilseed rotation) on carabid beetle activity density, diversity, and community structure in corn (Zea mays Linnaeus, Poaceae) at La Pocatière, Québec, Canada. Carabid beetles were sampled monthly from May to September 2006, using pitfall traps. Although 19 carabid species were observed, assemblages were dominated by Harpalus rufipes (De Geer), particularly in the second half of the season. Multivariate analyses indicated a strong affinity of carabid species for the NT treatment throughout the season. Crop sequence and tillage had no effect on diversity (Shannon's H′ ≤ 1.3) and evenness of carabid assemblage, but species richness and activity density were greater in NT than in tilled systems. Peak activity density of dominant species occurred at different times during the season, generally in accordance with preferred breeding season. Many species had greater activity density in NT than in tilled treatments. Because of their granivorous feeding habit, carabid populations such as that of H. rufipes could be an important asset to NT, given the limited weed management options available for this system.

We tested the hypothesis that the conophagous Douglas-fir cone gall midge, Contarinia oregonensis Foote (Diptera: Cecidomyiidae), responds to infrared (IR) radiation and other electromagnetic wavelengths associated with cones of Douglas-fir, Pseudotsuga menziesii (Mirbel) Franco (Pinaceae). Early-season (March–April) thermographic images showed that cone orientation (upright, horizontal, pendant) and cone colour (green, purple, green/purple) did not affect apparent cone temperature (inferred from thermographic images). Tree components significantly differed in apparent temperature with foliage being coolest and branches warmest. There was no significant difference in the number of larvae in cones of different colours, and adult midges were equally attracted to traps painted green or purple, suggesting that cone colour does not affect oviposition decisions by gravid females. Adult midges were more strongly attracted to warm traps with IR frequency emissions higher than the background than to cold traps with IR frequency emissions lower than the background. They were also more strongly attracted to warm branch-shaped traps than to warm can-shaped traps. Collectively, these data indicate that the shape and IR attributes of Douglas-fir branches may serve as foraging cues for C. oregonensis.

We tested whether the known bird-biting mosquito, Culex pipiens Linnaeus (Diptera: Culicidae), is attracted to human hosts by placing humans at ground level (∼1.5 m) or in the forest canopy (∼5 m) in a Niagara woodlot. Modified Centers for Disease Control (CDC) miniature light traps (no light, no CO2) were placed next to the human hosts to capture the attracted mosquitoes. The human-baited traps were compared with control traps (standard CDC miniature light traps with CO2, but no light). As expected from previous research, there were more C. pipiens captured at the higher elevation than at ground level. Generally, they were attracted to control traps more than to human-baited traps at 5 m, whereas at 1.5 m there was no difference between the two trap types. As a comparison, most Aedes vexans (Meigen) mosquitoes were captured at the 1.5 m elevation but there were significantly more captured in the control traps than the human-baited traps during all periods. Because C. pipiens is attracted to humans throughout the entire season at the 1.5 m height (where they might encounter humans), it is likely that C. pipiens can serve as a bridge vector of West Nile virus (WNV).

A well-accepted function of courtship in sexually dimorphic and cannibalistic spiders is suppression of female predatory responses. We quantitatively analysed courtship in the western black widow, Latrodectus hesperus Chamberlin and Ivie (Araneae: Theridiidae), to determine the behavioural elements of the males’ courtship that are correlated with mating success and/or the females’ responses. The 58% of males that engaged in web reduction elicited fewer aggressive responses from females and induced female quiescence more quickly than did males not exhibiting web reduction behaviour. Our data suggest that web reduction by male L. hesperus functions in sexual communication, a context not previously explored.

Nymphs of lotic mayflies live in environments that are expected to give rise to different degrees of population structuring. Here we investigate two taxa adapted to different lifestyles. Baetis macani Kimmins (Ephemeroptera: Baetidae) lives in flowing water; brooks that may periodically dry out in the summer or freeze to the bottom in winter. Baetis jaervii Savolainen is mostly found in sedge belts along the shores of lakes. Most insects living in flowing water show low levels of among-population genetic differentiation within and among catchments. Levels of differentiation in the lotic species are therefore assumed to be lower than in lentic B. jaervii. Here we test this hypothesis. Mitochondrial DNA and allele frequencies of nuclear genes were used to detect population structure in specimens originating from an extensive area from northern Finland. The genetic differentiation among populations of the lotic B. macani is more than twice the corresponding value for the lentic B. jaervii (FST 0.33 versus 0.15, while the mean FST between species was 0.33 and significant). The result is congruent within the cytochrome c oxidase subunit I gene (COI) partial gene frequencies. We argue that the significant genetic population structure, which only was found in the lotic B. macani, is differentiated as a consequence to the unpredictable environment as contrasted to the stable environment in standing bodies of water.

Predatory insects and spiders were collected from apple orchards in two geographic regions of Central Washington State, United States of America to assess seasonal phenology and diversity of the generalist predator community. Arthropods were collected from orchard canopy every 3–7 days over two growing seasons (March–October) at seven organically managed and two insecticide-free orchards. Over 35 000 specimens and 80 species of spiders (Araneae), ladybeetles (Coleoptera: Coccinellidae), lacewings (Neuroptera), and predatory true bugs (Hemiptera) were collected. Composition of insect and spider communities differed between the two geographic regions. Indicator species analysis identified several species that had a significant association with one of the two regions. Counts of the most common taxa were examined in detail on a calendar date basis to determine seasonal phenology of adult and immature stages. We observed substantial differences among taxa in number of generations, seasonal timing of first appearance in orchards, overwintering stages, and seasonal occurrence of the adult and immature life stages in orchards. Understanding seasonal phenology of natural enemies in orchards is a core requirement in integrated pest management programs for apple pests, and results of this study provide this information for the generalist predator community of orchards in the Pacific Northwest.

Little is known about the acarofauna associated with wood-boring beetles in Canada, including long-horned beetles (Coleoptera: Cerambycidae). Herein, we assessed the prevalence, abundance, diversity, phenology, and attachment location of mesostigmatic mites (Acari: Mesostigmata) associated with Monochamus scutellatus (Say), and tested whether the abundance and prevalence of mites differed between male and female beetles. A total of 176 beetles were collected in two sites in eastern Ontario in 2008 and 2009 using Lindgren funnel traps baited with α-pinene and ethanol lures, and 71% of hosts had mesostigmatic mites. A total of 2486 mites were collected, representing eight species, four genera, and three families (Digamasellidae, Trematuridae, and Melicharidae). Average prevalence was variable across mite species, and the number of mites per infested beetle also varied across species. Many of the mite species collected in this study have been reported from other cerambycid species, as well as from other wood-boring beetles, such as bark beetles. There was no significant sex bias in the abundance or prevalence of mites between male and female M. scutellatus, which suggests that there is no selective advantage for mites to disperse on females. This study represents the first quantitative investigation of the mites associated with M. scutellatus in Canada.

Tetropium fuscum (Fabricius) (Coleoptera: Cerambycidae) is a Palaearctic wood borer that has been established in Atlantic Canada since at least 1990. Neither the number of instars nor methods for determining the instar of field-collected larvae have been documented for this species. Head-capsule width was measured for 949 T. fuscum larvae in order to determine the number of instars in this species, estimate the mean and variance of head-capsule widths associated with each instar, and identify whether head-capsule width is sexually dimorphic. Head-capsule width data were analysed using maximum likelihood analysis of mixture models and the Brooks–Dyar rule. Our results provide strong support for the existence of six larval instars, with sexually dimorphic head-capsule widths in instars five and six. The probability of misclassifying larvae into instar-specific and sex-specific categories ranged from 0.6% to 12.8%, with the highest probabilities occurring when assigning a sex to fifth-instar and sixth-instar larvae.

Assessing biodiversity is essential in conservation biology but the resources needed are often limited. Citizen science, by which volunteers gather data at low cost, represents a potential solution for the lack of resources if it produces usable data for scientific means. Scientific inventories for butterflies are often performed with a Pollard transect, a standardised surveying technique that generates high-quality data. General microhabitat surveys (GMSs) are potentially more appealing to amateurs participating in citizen science projects because they are less constrained. We compare estimates of butterfly species richness acquired by Pollard transects to those obtained by GMSs. We demonstrate that GMSs allow surveyors to detect more butterfly species and a more complete portrait of local butterfly assemblages for the same number of individuals captured.