Studies based on presence/absence of a species may provide insight into habitat associations, allowing the distribution of species to be predicted across the landscape. Our objective was to characterize the carabid fauna in three mature boreal forest types (conifer, mixedwood, and deciduous) and a disturbed habitat (clearcut) to provide baseline data on the carabid species inhabiting the major forest types of boreal northwestern Ontario. Only spring-active carabids were considered for logistical reasons. We further identified the coarse woody debris structure and microhabitat characteristics within these stand types to try to refine our ability to predict the within-stand occurrence of carabids. We found the carabid composition of deciduous stands (mixedwood and aspen) similar and typical of the carabid fauna found in mixedwood forest in other nearby studies. The important feature of these forest types may be the presence of a deciduous leaf litter layer. In contrast, spruce stands contained fewer species and individuals and a distinct carabid fauna. As predicted, the clearcut habitats were dominated by open habitat species, although the fauna was dissimilar to what was recorded in clearcut habitats in other studies within northwestern Ontario. Coarse woody debris appeared to be an important habitat attribute for several carabid species in clearcut habitats.

During a survey of frog-biting corethrellid midges in Costa Rica, we collected 79 female Uranotaenia lowii Theobald, mosquitoes known to bite frogs, from seven lowland localities using the recorded calls of a frog. The calls of male barking tree frogs, Hyla gratiosa LeConte, were repeated about once per second, lasted about 0.15 s, and had a fundamental frequency near 450 Hz. We suggest that this frequency is within the range of acoustic sensitivity of the female mosquito antennae. Males of several families of Nematocera use sound to detect flying females of their own species, but we believe ours is the first observation of female mosquitoes being attracted by the sound of a host.

A model is presented which describes the effect of sterile male release on a wild population. This model is not subject to restrictions, such as equal competitiveness between normal and sterile males and sperm nor to insect species whose females mate only once. The model is an approximation as it assumes constancy in several dynamic population variables. However, it has application in determining the approximate effects of sterile male release and in decisions on the number of sterile males required for release programs. It also has uses in ecological research.

A widespread epizootic of the fungous disease caused by Entomophthora grylli Fres. occurred among grasshoppers in Saskatchewan in 1963. Camnula pellucida (Scudder), in particular, suffered high mortality and was nearly wiped out in those areas of central and east-central Saskatchewan where heavy infestations had been present. Weather was warm and humid during the outbreak with above normal rainfall in the seriously affected areas.

Field-cage studies showed that proper timing of rainfall was essential for continuation and spread of the disease. Rainfall shortly after death of the diseased grasshopper induced profuse growth of conidiophores along with intense discharge of conidia. When death occurred during hot, dry weather, no sporulation was noted and the insects rapidly dried up. The interval from infection to death of the grasshopper was about 13 days.

The fungous disease also developed in natural field populations of Melanoplus bivittatus Say, but none was noted in field cages where this grasshopper was being reared alongside of or together with C. pellucida that were dying continuously from the disease; this suggests that different strains of E. grylli were involved.

Rove beetle species and their pitfall trap abundance were studied in red spruce (Picea rubens Sarg.; Pinaceae) stands in the Acadia Research Forest, New Brunswick, Canada, in 1999. The study yielded over 5000 specimens representing 134 species in 11 subfamilies of Staphylinidae. Of these, 58 species represent new distribution records for New Brunswick (NPR), including 15 new distribution records for Canada (NCR), 6 new species, and 4 synonyms, as follows: Omaliinae, 3 species; Proteininae, Proteinus pseudothomasi Klimaszewski sp. nov. (NCR, NPR) and P. acadiensis Klimaszewski sp. nov. (NCR, NPR); Tachyporinae, 3 species; Trichophyinae, 1 species; Aleocharinae, 33 species, including Atheta capsularis Klimaszewski sp. nov., A. brunswickensis Klimaszewski sp. nov., A. pseudocrenuliventris Klimaszewski sp. nov., Oxypoda lacustris Casey (NPR) [= O. bradorensis Lohse syn. nov., O. egestosa Casey syn. nov., O. lassula Casey syn. nov., and O. optiva Casey syn. nov.], and Pella gesneri Klimaszewski sp. nov.; Oxytelinae, 3 species; Paederinae, 3 species; and Staphylininae, 10 species. The new species or known species representing new records for Canada are presented here with a short diagnosis, habitus images, and genital illustrations to help with identification. The habitus images and most genital illustrations are presented here for the first time for these species.

Dendroctonus brevicomis Lec. responded in flight to combinations of insect- and host-produced volatiles. Emergent female beetles crushed at −70 °C, as well as synthetic exo-7-ethyl-5-methyl-6, 8-dioxabicyclo [3.2.1] octane (“brevicomin”) attracted both sexes of the western pine beetle when offered with oleoresin freshly tapped from the host, Pinus ponderosa Laws. Offered separately, these materials were inactive. Crushed emergent Dendroctonus ponderosae Hopk. males per se, however, attracted flying D. brevicomis in appreciable numbers. Dominance of either host odor or insect pheromone appeared to govern the sex ratio of the responding insects.

The adults, mummies, and final-instar larvae of the eight hymenopterous parasites of the pea aphid, Acyrthosiphon pisum (Harris), in Eastern Canada are described and illustrated. The history, synonymy, and biology of each species, and the problems of species differentiation in two of the genera, Aphidius and Praon, are discussed. Keys are given to separate the adults, mummies, and cast skins of the last larval instar.

The adult Arthropoda occurring in, on, or emerging from 2,660 sporophores of the bracket fungus Polyporus betulinus (Bull.) Fr., growing on dead birch, are listed. Collections were made in New Brunswick, Quebec, Ontario, and Manitoba. Two hundred and fifty-seven species of Arthropoda, mainly insects and mites, were recorded; over 49,000 specimens were examined. Old, twice-wintered sporophores produce more species and more individuals. In general, the fungus is rich in species but rarely produces sizable populations of any one species.

Stands of trembling aspen in Manitoba and Saskatchewan are frequently attacked by the forest tent caterpillar, Malacosoma disstria Hbn. The recent history of attack is reviewed in this paper to determine if there is evidence of a consistent pattern of outbreaks and if the latest of these had any appreciable effect on aspen stands in the two provinces.

The recent introduction of the concept of refuge areas for the management of the Colorado potato beetle, Leptinotarsa decemlineata (Say) (Coleoptera : Chrysomelidae), on resistant potato highlighted the existence of important gaps in our knowledge and understanding of this pest's movement within and between habitats. The objective of this review is to synthesize the information available for the benefit of crop managers and to identify subject areas in need of additional research. A traditional, somewhat encyclopedic, review of the old and recent literature on research methods, basics of flight and walking, as well as abiotic and biotic conditions for dispersal, revealed a considerable volume of information accumulated since the early 1900s. There is a consensus on the role of abiotic factors on flight and walking, but a better understanding of the biotic factors will be required before the variability of the dispersal response can be fully explained or predicted. Cybernetic models of orientation proposed in the literature were pulled together into a schematic representation of the orientation process in walking L. decemlineata. The model begins the integration of the different conditions and underlying suggested mechanisms responsible for the orientation of the walking beetle. There is remarkably little information on the orientation of potato beetles during flight. Finally, the seasonality of walking and flight dispersal is reviewed in relation to the host habitat and overwintering sites.

The niche breadth and overlap in nesting preferences of 15 species of bumble bees were investigated in Alberta. Some of the factors that influence the distribution of nesting sites and abundance of species and permit the species to coexist in sympatry are discussed. Artificial domiciles were used as potential nesting sites. Some species were specialists in terms of nest site selection while others were generalists. The few natural nests found, the long periods spent by queens searching for nests, the high frequency of usurpation or direct interference and death of intruders, and the frequency of high niche overlap values between species are evidence that nesting sites are limited and are incompletely partitioned among the coexisting species. Usurpation also demonstrates the competition among individuals and species. Phenological differences in nest establishment influence the competition among the species. Camouflaging of tunnels presumably reduces the intensity of usurpation and protects queens and the brood from inclement weather and from social parasites (e.g., Psithyrus) and predators.

Populations of the fir engraver reached epidemic proportions and then declined to a very low level over the study period (1964–71). However, population density within infested trees showed an inverse relationship to overall population trend. The population trend over the past 40 years was associated to some degree with rainfall deficits and with Douglas-fir tussock moth outbreaks.

The major contribution to total mortality in each generation occurred in the larval, pupal and pre-emergent adult stages, next was adult mortality and infecundity, while egg mortality was of least significance. Mortality and infertility of parent females was mainly caused by nematode parasites although host resistance resulted in a significant number of attack failures. Parasitism by a phorid fly was of minor importance. Nematode parasitism appeared to be density-dependent in relation to overall population size.

Most egg mortality resulted from host resistance which was inversely related to egg density within trees. Other egg mortality occurred in a density-independent manner.

Mortality between larva and brood adult stages was mainly attributed to intra- and interspecific competition. The impact of these factors was directly related to within-tree larval density. Nematode parasitism was related to overall fir engraver population size and to per cent infection of attacking females. Predator activity was weakly density-dependent and mortality caused by resinosis was inversely related to fir engraver density. Parasitism and other mortality factors appeared to be independent of host density.

An hypothesis is presented for the population behavior of the fir engraver; population fluctuations being determined by the quantity of susceptible trees and ultimately regulated by intraspecific competition. Nematode parasitism and interspecific competition were regarded as modifying, and perhaps sometimes regulating, abundance. Areas needing additional study, particularly host-tree physiology are discussed.

Larvae of the wheat stem sawfly, Cephas cinctus Nort, reduced the weight of grain per head by an average of 17.3% in the two spring wheats Red Bobs and Thatcher with annual reductions varying from 10.8% to 22.3%. They also lowered the protein content in Thatcher by an average of 0.6% and a maximum of 1.2%. However, because a significant loss in protein content occurred in only 1 of 6 years in Red Bobs, the effects of the larvae on protein content cannot be generalized for all varieties.

The losses in weight per head resulted from a mean reduction of 11.9% in the weight of the kernels combined with a mean reduction of 1.9 in the number of kernels per head. The larvae caused the losses by feeding in the stems and by cutting them when the moisture contents of the kernels were relatively high. Annual variations in losses were attributed to the dates of the infestation, to the amount of precipitation in July and August, and to differences in dates of cutting by the larvae.

Solitary cavity-nesting bees, especially trap-nesting Megachilidae, have great potential as commercial pollinators. A few species have been developed for crop pollination, but the diversity, abundance, and potential pollination contributions of native cavity-nesting bees within agricultural systems have seldom been assessed. Our objectives were to compare the diversity and fecundity of cavity-nesting bees in Nova Scotia in natural ecosystems with those in apple orchards under three levels of management, using trap nests, and to determine whether any native bees show promise for development as pollinators. Our results show that species richness and numbers of bees reared from trap nests in commercially managed orchards, abandoned orchards, and natural habitats were similar, and species’ compositional patterns were not unique to specific habitats. Trap nests can be used to increase and maintain cavity-nesting bee populations within Nova Scotia apple orchards. Osmia tersula Cockerell (Megachilidae), which accounted for almost 45% of all bees captured and was the most abundant species nesting in all habitats evaluated, should be assessed for potential as a commercial pollinator of spring-flowering crops. The influence of natural cavities on bee species richness in trap-nesting surveys is also discussed.

The flight capacity (duration and velocity) is an important phase of the flight behaviour of economically significant insects such as the Douglas-fir beetle, because it influences the feasibility of control or preventive measures which might be considered. An understanding of the flight capacity and how it varies in relation to environmental factors is necessary to evaluate the beetles' power of dispersal under different seasonal conditions. This would help to detect new areas of infestation by directing or narrowing the search. It also would help evaluation of the hazard at hand in timber surrounding the infestation and be a further aid in determining the size of areas of sanitation required around the comparatively beetle-free areas needed for special purposes, such as parks.

Male Ips paraconfusus selected a host, ponderosa pine (Pinus ponderosa), over a non-host, white fir (Abies concolor), only after the beetles had bored through the outer bark and into the phloem. Males, when given a choice between bark discs of these tree species in petri dishes, bored readily through the outer bark of either species. However, the beetles penetrated no more than 1 mm into the phloem of white fir, but they bored extensively in the phloem of ponderosa pine. The beetle’s preference for the pine over fir phloem was apparent with intact samples of phloem with the outer bark removed and with ground phloem. No preferences were apparent for the ground or intact pine or fir outer bark, with the phloem removed. The beetles bored preferentially in fissured as opposed to smooth outer bark of either tree. Beetles did not feed in the outer bark but did feed in the phloem of either species. In field experiments beetles attracted to logs of pine and fir bored through the outer bark of each species in nearly equal numbers. In white fir they re-emerged and departed soon after penetration of the phloem, whereas in ponderosa pine they continued excavation of tunnels in the phloem. In contrast, few beetles penetrated even the outer back of incense cedar (Calocedrus decurrens), another non-host species.

Ten species of predatory coccinellids representing seven genera were reared from the first-instar larva to the adult stage on dry powdered aphids. Dry pea aphids, Acyrthosiphon pisum (Harr.), and corn aphids, Rhopalosiphum maidis (Fitch), were both superior to bean aphids, Aphis fabae Scop., for growing coccinellid larvae. Though Anatis mali Auct. grew equally well on A. pisum and R. maidis, the larvae generally lived longer when starved after feeding on R. maidis. Dry aphids were as good as living aphids for growing A. mali and Coleomegilla maculata lengi Timberlake. C. maculata grew as well in darkness as in light, and an aphid–pollen mixture was superior to either component alone. Three generations of C. maculata were reared on a yeast diet and this diet is the most promising food for use to supplement natural foods in the field. An arrangement of coccinellid species on the basis of their food specificity does not correspond to the current phylogenetic arrangement, as the taxonomically primitive tribe Coccinellini contains both generalized and selective feeders.

It is universally recognized that the spatial distribution or pattern of animals and plants in nature is neither uniform nor truly random. In order to study a biological community quantitatively, or to assess the densities of living organisms in their habitats, ecologists have found it profitable to sample the space in which the organisms occur. The distribution of the number of individuals per sample is of fundamental importance.

Of the 21 Nearctic species of Pyrobombus Dalla Torre 11 are known to occur in southern Alberta. Distribution, macrohabitat, microhabitat, and period of nest establishment of the 11 species are compared. The behavioral patterns of camouflaging entrances to underground and false-underground hives, gathering material for nests, constructing first- and succeeding-brood egg cells, producing second-generation colonies, storing honey and pollen and producing wax, superseding intra- and inter-specifically, and mating and hibernating are compared both intra- and inter-subgenerically. Most of the behavioral patterns were common to all southern Alberta species of Pyrobombus; some were common only to certain species indicating a close relationship between these species, and one pattern was common to species in two subgenera but to only 4 of the 11 species of Pyrobombus. Thus, evolutionary trends were indicated. The enemies Psithyrus spp., Volucella bombylans (L.), and inclement weather are discussed.

The age at which Pseudaletia unipuncta females initiated calling varied with temperatures experienced during pupal and adult stages. Entrainment was induced by temperatures during pupal development if similar to or lower than temperatures during adult life. However, adult temperatures were of major importance if lower than those experienced during pupal development. These observations were generally supported by data from field experiments repeated at different periods of the summer. The possibility that entrainment occurs at a specific period of development is proposed to explain certain field observations.

Changes in mean onset time of calling and the time spent calling also varied, although generally not in the same manner as reported for other species. Differences in the life cycles, particularly the site of pupation, are proposed to explain these discrepancies.