We describe a model which estimates grasshopper body temperature (Tb) by linking energy-flow equations with empirical descriptions of aboveground gradients of air temperature (Ta) and wind speed. The model was tested using restrained grasshopper nymphs; estimated and observed Tb agreed well (r2 > 0.81). At a rangeland site near Lethbridge, Alberta, Canada (49 °42′N, 112 °48′W), we observed 315 free-living grasshoppers. We recorded the shadow each cast on a horizontal surface, then reconstructed their orientation to the sun by geometric analysis. We used the model to estimate their Tb and the range and frequency of possible Tb within their environment. Modelled Tb exceeded Ta, and was generally lower than the modelled maximum possible Tb, but was well correlated with Tb of insects on top of the dense layer of vegetation which pervaded the site. This observation suggests that behaviours which elevate Tb are constrained by environmental barriers. Tb exceeded the value expected if insects were located and oriented randomly within their environment (mean difference = 3.95 °C, SE = 0.115); this is unequivocal evidence for behavioural thermoregulation. Heuristic simulations using temperature-dependent developmental- and feeding-rate equations for Melanoplus sanguinipes (Fabricius) suggest that thermoregulatory behaviour increased these rates by 30–40% compared with those for insects located and oriented randomly within their environment. During this study, population processes were never inhibited by excess heat; therefore any climatic warming at the experimental site will probably accelerate the phenology of these grasshopper species. Effects at other sites may differ; the model can be applied to test this possibility.

The birch skeletonizer Bucculatrix canadensisella Chambers was univoltine in central Alberta in 1992 and 1993. Adults occurred from early June until the end of July, and larvae were present from early July on, co-occurring with larvae of the ambermarked birch leafminer, Profenusa thomsoni (Konow). Larval B. canadensisella densities were higher in 1992 than in 1993, and were higher on rural trees at George Lake than on urban ones in Edmonton.

The gregarine, Leidyana canadensis Clopton and Lucarotti was found infecting the guts of larvae in a declining population of the hemlock looper, Lambdina fiscellaria fiscellaria (Guenée), in Charlotte County, New Brunswick. Total mortality, in rearing, of field-collected larvae and pupae was 75.5% in 1993 and 89.2% in 1994. Leidyana canadensis infections were present in 60.1 and 80.5% of these dead insects in the two respective years. The incidence of L. canadensis in larvae that died in rearing was greater than 50% for all instars except those collected in the fifth instar, where the incidence was below 30%. Gregarine infections were present in first-instar larvae on the first days of collection for both years and, in 1994, 74% of all first-instar larvae collected were infected with L. canadensis. Of 678 larvae collected in 1994, 73 survived to adults and, of these, 44 had harbored L. canadensis as larvae. The incidence of other microbes and parasitoids in dead larvae and pupae is also reported.

The purpose of this study was to explain a peculiarity of resource use by two sympatric bumble bee species. In one study area, pronounced resource partitioning was observed: Bombus terricola Kirby was confined to Asclepias syriaca L. and Bombus ternarius Say to Apocynum androsaemifolium L., and yet in another area both species frequented Apocynum. Measurements of floral characteristics and forager behaviour on Apocynum led to an hypothesis regarding floral use by two bumble bee species: B. terricola is relatively inefficient at flying between flowers, and so tends to visit Apocynum only in areas where the plants are closely spaced. Half of the patch of Apocynum was clipped so as to decrease flower density, with the expectation that, as a result, the frequency of B. terricola relative to B. ternarius would be reduced. The prediction was confirmed. The results underscore the role of context in floral use by bees.

In an oil palm plantation in northeast Sumatra, Indonesia, we tested the hypotheses that selection of pupation site by female bagworms, Metisa plana (Walker), influences the distribution of emergent larvae, and that intertree dispersal by larvae is density dependant. Similar intratree distributions of empty female pupal cases and early instars and significant regressions between numbers of female pupal cases and larvae per leaf for 36 out of 39 palms indicated that larvae generally remain on the same leaf where they emerged. Proportions of early instars per female pupal case decreased with increasing densities of female pupal cases per tree and were greater on trees surrounding most heavily infested palms, suggesting that intertree dispersal of early instars is density dependent. Interspecific comparisons of life history constraints between M. plana and the allopatric bagworm Oiketicus kirbyi (Guilding) reveal different selective pressures that may have converged and favoured the development of an identical life history trait.

Relatively little information concerning the cuticular hydrocarbon composition of aquatic insects is known. The cuticular hydrocarbons of the aquatic beetle Agabus anthracinus Mannerheim have been identified with the aid of a gas chromatograph coupled to a mass spectrometer. The cuticular hydrocarbon profile comprises n-alkanes (46.8%), n-alkenes (27.1%), and methylalkanes (25.9%) and is basically similar to that of terrestrial Coleoptera. However, the hydrocarbons of A. anthracinus differ in that (i) the shorter chain n-alkanes are present in higher proportion, (ii) there is a relatively lower abundance of methylalkanes, and (iii) the proportion of n-alkenes is significantly higher.

The genus Bdelyrus Harold is revised. Twenty new species are described: B. amazonensis, B. apaporisae, B. boliviensis, B. braziliensis, B. bromeliatilis, B. genieri, B. gilli, B. grandis, B. howdeni, B. iauaretensis, B. laplanadae, B. leptomerus, B. lobatus, B. metaensis, B. paraensis, B. parvoculus, B. parvus, B. pecki, B. peruviensis, and B. triangulus. Separate keys are given for males and females. Descriptions, illustrations, and range maps are provided, and a phylogenetic analysis is included.

The study of bee diversity and activity was conducted from January until June 1994 in a natural vegetation parcel (6200 m2) in Constantine (Algeria). The results showed the presence of 10 genera of wild bees visiting natural flowers and belonging to four families: Andrenidae, Anthophoridae, Halictidae, and Megachilidae. The Apidae family was represented by honeybee (Apis mellifera L.) and bumblebee (Bombus ruderatus siculus Dalla Torre et Friese). Census of bee populations revealed the abundance of wild bees with 66.26% of flowers visits, honeybee with 31.98%, B. ruderatus and Xylocopa violacea with 1.59 and 0.17% of total fauna, respectively. The beginning flight activity of these species started from a minimum threshold of temperature and humidity. The alimentary specialization was quantified by Simpson’s diversity index (Is) and by Shannon’s diversity index (Ish). Apis mellifera had the highest floral visits index (Is = 0.866) and the broadest alimentary niche index (Ish = 0.316).

We examined the effect of forest structure and climate on large-scale and long-term patterns of outbreaks of forest tent caterpillar, Malacosoma disstria Hbn., across central Ontario. This was done using previously published data on outbreak duration and forest heterogeneity, combined with high-resolution climatic data simulated by the recently developed Ontario Climate Model. Our analysis, which eliminates some of the spatially confounding effects of forest structure and climate, suggests that both the predicted long-term temperature minimum for the coldest month and the predicted growing degree-days in the first 6 weeks of the growing season are important determinants of outbreak duration, with colder weather being associated with shorter outbreaks. Forest heterogeneity accounts for more variation in outbreak duration than either of the climatic variables.

Preserved Coleopteran remains dating to the last quarter of the 17th century were recovered from historical latrine or privy contents in Boston, Massachusetts. This analysis yielded 15 individuals of the striped flea beetle, Phyllotreta striolata (Fabricius). Its presence represents the earliest known record of this species in North America and demonstrates that it was introduced at least a century earlier than previously thought. The species history and possible modes of introduction are discussed.

Studies were conducted to evaluate the ability of six commercially available species of Trichogramma to parasitize eggs of tomato pinworm (TPW), Keiferia lycopersicella (Walsingham), and their potential use for biological control of TPW eggs. Of the six species, Trichogramma pretiosum Riley and Trichogramma brassicae Bezdenk parasitized the most TPW eggs (40–50%). Further studies assessed the effectiveness of T. pretiosum and T. brassicae as biological control agents for TPW eggs under controlled environmental conditions which simulated conditions that could be found during the greenhouse crop production season. Trichogramma pretiosum caused significantly higher mortality of TPW eggs than did T. brassicae at all parasitoid to host egg (P:H) ratios. Mortality caused by host feeding and stinging increased significantly with increasing P:H ratios for both species. Parasitism by T. pretiosum on TPW eggs was reduced significantly and mortality caused by feeding and stinging increased significantly at 28 °C, compared with those at 20 and 25 °C. No differences were found in parasitoid-induced mortality when T. pretiosum were offered 1-, 2-, or 3-day-old TPW eggs, but parasitoid-induced mortality was reduced significantly when parasitoids were offered 4- and 5-day-old TPW eggs. Based on these trials, a P:H ratio of between 1:1 and 10:1 is recommended for inundative releases of T. pretiosum for control of TPW on greenhouse tomatoes.

During a study on the parasitoids of the imported cabbageworm, Artogeia rapae (L.) (Lepidoptera: Pieridae), undertaken in 1993 and 1994, we recovered Cotesia rubecula (Marshall) (Hymenoptera: Braconidae) for the first time in Quebec, Canada. Samples were taken from pesticide-free plots of cabbage, broccoli, and Brussels sprouts located at Ste-Clotilde (45°09′N, 73°41′W) and L'Acadie, Quebec (45°18′N, 73°21′W), as described by Godin and Boivin (1998). In addition, survival of diapausing C. rubecula was evaluated after a 5-month incubation at 4°C (Godin 1997). Both A. rapae and C. rubecula are introduced species and originate most likely from Europe (Richards 1940). Artogeia rapae was discovered in 1860 in Quebec (Harcourt 1963), and C. rubecula was first reported in 1963 in British Columbia (Wilkinson 1966).