In 1976 and 1977, adults of Aedes sticticus (Meigen) and Aedes vexans (Meigen), marked with fluorescent dust, were captured in light traps up to 33 days after release and at distances up to 11 km from the release site. Adults flew primarily northwest from the release sites, and with the prevailing winds. Porcine and bovine hosts present at some of the trapping sites, appeared to be highly attractive to female mosquitoes. Within an 8 km trapping radius of the release site, the mean number of marked/trapped female mosquitoes decreased with distance. In 1977, 50% of the marked captures (weighted according to km2 of trapping area) were taken within the first 2 km, 82% within 4 km, 92% within 6 km, and the remainder out to 8 km from the release site. For all trap sites, the mean recovery of marked/unmarked adults over a 33 day trapping period in 1977 was 1:1113.

Larvae of the mountain pine beetle, Dendroctonus ponderosae Hopk., were reared to adults in naturally infested bolts of lodgepole pine, Pinus conforta Dougl. var. latifolia Engelm., at 21 ± 3 °C. The mean pronotal width of the emerging beetles of both sexes decreased, and the male:female ratio increased, during the emergence period. On the average, larger individuals of both sexes survived longer when adult beetles were stored at 1 ± 2 °C. Also, the male:female ratio of the surviving beetles decreased with increased storage duration. These and related results in the literature suggest that in natural populations of the mountain pine beetle average adult size increases, and the male:female ratio decreases, following stress-induced mortality in the larval and(or) adult stages.

We describe a method for identifying conifer-feeding species and lineages of Choristoneura Lederer in Canada and Alaska. The method relies on amplification of mitochondrial (mt) DNA by the polymerase chain reaction (PCR); amplified DNA is then digested with restriction enzymes to give characteristic DNA fragment patterns. We used the cytochrome oxidase I and II genes of mtDNA, which were previously shown to contain numerous nucleotide differences at the level of species. Ten restriction enzymes were surveyed and a combination of two of these (EcoR V + Hinf I) was sufficient to distinguish the major mtDNA lineages. Choristoneura fumiferana (Clemens), C. pinus Freeman, and C. rosaceana (Harris) were readily distinguished from each other and from an assemblage of three putative western species (C. occidentalis Freeman. C. orae Freeman, and C. biennis Freeman). The three western species have the same mtDNA marker pattern in most individuals and, although ecologically differentiated, their populations may actually be conspecific. At one locality in Alaska, pheromone traps bailed with lures for C. fumiferana attract moths with C. fumiferana mtDNA, and lures for C. orae attract moths with mtDNA that is characteristic of the western assemblage. This demonstrates geographic overlap of genetically distinct species in Alaska. The same two separate mtDNA lineages co-occur at two localities in Alberta, but pheromone attraction is unknown. In British Columbia, populations identified as C. biennis and C. occidentalis contain a few individuals with divergent mtDNA genotypes, the significance of which remains unclear. Amplified mtDNA thus provides a convenient, reliable marker for surveying genetic variation within species and for studying interactions among species of the C. fumiferana group.

Field plot tests during two seasons show that augmentative releases of Perillus bioculatus can control first-generation eggs and larvae of the Colorado potato beetle (CPB) under Quebec short-season conditions. Stinkbugs mass-reared on CPB were introduced manually as 2nd- and 3rd-stage nymphs during spring oviposition of the beetle at densities of one nymph per 50–225 CPB eggs recruited per plant, in 0.025-ha plots. Sampling at intervals of 1–3 days measured predator establishment, CPB egg and larval mortality, and foliage protection level. Direct observations were used to document predator-prey relationships and to determine weather conditions favourable to P. bioculatus.

In the 1 st-year test, with predators released over all plants within plots, CPB control was compared among: (1) stinkbugs alone, (2) the bioinsecticide Bacillus thuringiensis (BT) as Trident™, (3) a combination of both control alternatives, and (4) no protection against the CPB. BT and stinkbugs, both alone and in combination, produced significant control as measured by percentage reductions in prepupal drop to the ground, new adult emergence, and foliage protection. Only treatments involving P. bioculatus reduced CPB egg eclosion which was the key control factor; it is strongly correlated with overall control level.

In the 2nd-year test, predators were released in a central area comprising only 25% of all plants within plots. Predator and CPB egg mass densities were manipulated to produce predator: prey ratios of 0:1, 0:2, 1.5:2, 1.5:1, 3:2, and 3:1, representing average ratios of 0, 1.5,or 3 P. bioculatus per plant, and 1 or 2 CPB egg masses per plant at release time. As expected, central release produced complex interactions between control, and predator and prey densities. High beetle density slowed predator emigration from the centre, more so at low predator density than at high predator density. Predators moved more quickly within the same row than across rows. CPB eggs were destroyed in large numbers in both years but in 1993, final control correlated with larval rather than egg predation. A maximum 80% reduction in prepupal drop to the ground was obtained at the 3:1 predator:prey ratio (1 P. bioculatus:95 CPB eggs recruited per plant).

The results prove the efficacy of P. bioculatus for biological control of first-generation L. decemlineata populations, at densities resulting in approximately 300 eggs laid per plant during spring oviposition in the study area. Despite low natural populations of P. bioculatus and unclear prospects for commercial availability at reasonable cost, it is evident that stinkbug releases have potential as a non-chemical control measure within an IPM program in Quebec potato production.

Results of the analyses for digestive enzymes in the glands and midguts of five species of ants showed that invertase is usually secreted by the maxillary glands, amylase by the salivary glands, and protease and lipase by the midgut. Lipase was found in the post-pharyngeal glands but observations indicate that it is not associated with the digestion of ingested food. Differences in the activity of the enzymes in different species tended to reflect the feeding habits of the ants.

Daily rates of predation by Podisus maculiventris (Say) (Heteroptera: Pentatomidae) on Mexican bean beetle larvae, Epilachna varivestis Mulsant (Coleoptera: Coccinellidae), were measured in soybeans, Glycine max (L.). The number of Mexican bean beetle larvae attacked per predator per day remained consistently low throughout 2 years of study. Estimates of the area searched by P. maculiventris were calculated from the number of prey attacked, number of prey available for attack, and leaf area. As leaf area increased, P. maculiventris searched more area, demonstrating a search strategy shared with other predators of canopy-inhabiting prey in soybeans.

The effect of attack by the ambrosia beetle Trypodendron lineatum (Olivier) on log attractiveness was studied using "greenhouse" cages, in which solar heating causes release of odor-bearing air beneath glass-barrier traps. In all eight replicates of a test, attack by female beetles was followed by a marked increase in attractiveness of logs. This "secondary" attraction was strong within 2–3 days after attack, continued for many weeks if females remained alone, but disappeared following mating.

A series of constant observations on Amblyseius largoensis (Muma) on excised avocado leaves in the laboratory revealed that the hunger level of this predator directly affected the time spent feeding on individual prey, the relative aggressiveness, the frequency of successful captures, the length of digestive pause, and the speed of movement. Feeding and nonfeeding periods occurred in constantly recurring cycles. Hungry predators captured 2–4 prey in succession; after each capture a digestive pause followed, the length of which increased (up to 7–8 h) as the predator became increasingly satiated. This cycle was repeated 2–3 times in 24 h. Several thresholds appeared to be responsible for this behavior pattern.

A simple, inexpensive, permanent method for individually marking Colorado potato beetle is presented. The method consists of puncturing the elytra within the cream-colored longitudinal bands using a minuten nadeln; the wound response produces intense melanization at the point of puncture. Division of a band into three zones, each potentially receiving a dot, produces an octal digit. If all eight bands are employed, more than 16 million beetles can be uniquely marked. No significant survival effects of marking were seen in teneral, post-teneral, or post-diapause adult beetles. Propensity to fly in mid-summer beetles was generally unaffected by marking. Probabilities of mismarking and misreading are negligible if sufficient care is employed.

In Western Canada, Melanoplus bilituratus (Wlk.) may hatch from early May to mid-July, depending on seasonal conditions. Little information is available on the relationship of time of hatching to population growth except that grasshoppers emerging too early in the spring may be destroyed by adverse weather that often occurs at this time (Shotwell, 1941). Also, it has beenassumed that grasshoppers hatching late in the summer mature too late to contribute much to general population growth.

Laboratory studies of the mean weights of initial eggs (Ei) of the spruce budworm, Choristoneura fumiferana (Clem.), show that this value is determined by the genetic constitution of the female moth and is relatively independent of environmental control. Dietary differences experienced by the female during larval development, and originating from different hosts or from reduced nutrient levels in artificial diets, did not affect Ei values; however, depletion of nutrients sufficient to reduce fertility greatly did reduce Ei. Temperature conditions during the ultimate larval and pupal stages influence Ei values which vary inversely. Mean egg weights are strongly heritable and are readily selected for, thereby demonstrating the presence of strong genetic control.

Rove beetles are useful subjects for Nearctic forest biodiversity work because they are abundant, diverse, and easily collected, and have strong habitat affinities. Excellent identification keys exist for most groups, although there is a dearth of ecological and life-history information. There is considerable variation in species composition and abundance within the active summer season and in abundance from year to year. Community composition varies among larger geographical regions and to a lesser extent among forest types in more localized areas. Within the Nearctic boreal forest there are significant differences between beetle communities from the eastern and western portions. For the most part, the same species tend to dominate rove beetle communities in the western boreal forest. At the landscape level there are differences in rove beetle communities along successional gradients. In the boreal forest the communities of younger aspen-dominated and older conifer-dominated stands are somewhat distinct, with intermediate-aged stands containing a mix of the two communities. At the ecosite and microsite level there is significant variation, which remains poorly understood. Fire is the dominant mode of disturbance in the Nearctic boreal forest. It has a profound effect on rove beetles by destroying the forest communities and resetting the successional trajectory to the earliest stages. The burn pattern results in a patchwork of different communities at various stages in the successional cycle. In contrast to fire, forest harvesting does not directly destroy the rove beetle community, but to a large extent it destroys the forest habitat. This results in a unique rove beetle community characterized by a mix of forest species and open-ground specialists, and overall high diversity in this period of flux. In the years after harvesting, the rove beetle community goes through successional changes and becomes more similar to the forest community, but it skips the early postfire stage and proceeds along the successional trajectory more rapidly than after fire. In at least one forest type in western Canada, the post-fire and post-harvest communities, though similar, have not converged after 29 years. Other less direct effects of harvesting on rove beetles are a decrease in the proportion of the land base suitable for communities associated with older successional stages; alteration of forests by post-harvest site preparations and planting of exotic tree species; edge and fragmentation effects that are detrimental to the remaining forest surrounding harvested areas; and an influx of exotic arthropod species with affinities for disturbed sites. More information is needed on the habitat affinities of individual species. It is recommended that future work explore the effects of post-harvest forestry activities, fragmentation, and edges on rove beetles in forested habitats. As well, such studies should consider the effects on beetles of riparian zones and wetlands.

Controlled mating experiments demonstrating total reproductive isolation, together with consistent differences in morphological and cytological detail, confirmed the validity of the closely related group IX Ips: grandicollis, cribricollis, lecontei, montanus, confusus, paraconfusus, and hoppingi. The latter two species, new to science, were formerly considered to be confusus.Matings between grandicollis from eastern Canada and North Carolina were subnormally fertile; other intraspecific matings between individuals of the same population or distant populations produced fully fertile progeny. Interspecific pairings usually resulted in insemination and normal-appearing egg galleries, but, with one exception, none of the eggs hatched.One montanus and two confusus, each mated by males of the same species, produced all-daughter broods. This "sex-ratio" condition appeared to be the result of a matrilineally transferred cytoplasmic factor lethal to male embryos only.At first meiotic metaphase all species had the karyotypic formula 15 AA + Xyp, and only grandicollis was easily differentiated by bivalent configuration or size sequence. Most other species showed diagnostic differences at meiotic prophase or second meiotic metaphase. Pairing disruptions and anaphase bridges occurred in grandicollis interpopulational hybrids; meiosis was normal in progeny from interpopulational pairings of confusus, paraconfusus, and montanus.In grandicollis the median struts of the male genitalia were 1.5 times longer than the median lobe. The struts/lobe ratios for other species approximated 1.00 but differences for most comparisons between species were statistically significant. The shape of the pars stridens on females was different for most species and mean widths of striations thereon ranged from 0.517 μ for paraconfusus to 0.876 μ for lecontei. This character provided absolute discrimination of females of confusus from those of paraconfusus and hoppingi but the latter two species were most easily separated by differences in the density of punctures in the elytral declivity.It is hypothesized that contiguous allopatry and differences in host and ecological specialization, evidenced in species of group IX, is maintained by their high propensity for interspecific mating which fails completely to produce progeny.

Superparasitism created a food shortage and thereby reduced survival and size of adult Nasonia vitripennis (Walk.) (Hymenoptera: Pteromalidae) reared on pupae of the house fly, Musca domestica L. Superparasitism also reduced the percentage of females in the adult progeny but had no effect on rate of development, ability to emerge, or incidence of diapause in N. vitripennis.

Differential survival, growth, and egg production were obtained for the bertha armyworm, Mamestra configurata Wlk., feeding on four natural host plants and one artificial diet. Highest survival, growth, and egg production were obtained among insects reared on the artificial diet. Foliage of potato was the only food which appeared to lack the nutritive qualities essential for adequate survival, growth, and reproduction. Larvae reared on this plant consumed significantly less food, had a poorer survival, accumulated less reserves in the form of tissue growth, developed into smaller pupae, and produced adults that were less fecund than those reared on other foods. Despite these differences, the approximate digestibility (AD), the efficiency of conversion of ingested food to body tissue (ECI), and the efficiency of conversion of digested food to body substance (ECD) obtained for insects feeding on potato, were very similar to values obtained for insects which were reared on other plants. On each diet a linear relationship was obtained between food consumption and growth.

A co-operative investigation to discover the factors necessary for egg production in the horn fly, Siphona irritans (L.), was begun in 1950 at the Lethbridge laboratory and the Department of Bacteriology, University of Alberta, Edmonton. Although there is an extensive literature on the horn fly, comparatively few publications deal exclusively with its life-history and habits. Information on the biology of this insect is found in a widely scattered literature dealing with muscids or dung-breeding insects in general. The dearth of information in recent years on this economically important insect may be caused in part by the fragmentary literature. This paper is a review of the available information on the life-history and habits of the horn fly, along with observations of the authors.

Knowledge of the effects of variables that can influence trapping results should help to optimise efforts in exotic species detection and other surveys. Two vertical trap placements (understorey, canopy) were tested to determine influence of these two heights on captures of Scolytinae (Coleoptera: Curculionidae), Cerambycidae (Coleoptera), and Siricidae (Hymenoptera) using semiochemical-baited multiple-funnel traps. Traps were baited with α-pinene, ethanol, ipsdienol, and ipsenol. A total of 8463 insects from 65 species and one genus were captured during the study. Average species richness, species diversity, abundance, number of unique species, and expected diversity were higher in understorey compared with canopy traps. Jaccard (0.94 ± 0.05) and Sørensen abundance (0.97 ± 0.03) similarity indices suggested highly similar communities sampled at the two trap heights. Dendroctonus valens LeConte, Dryocoetes autographus Ratzeburg, Hylastes opacus Erichson, Orthotomicus caelatus (Eichhoff), Gnathotrichus materiarius (Fitch), Asemum striatum (Linnaeus), Monochamus scutellatus scutellatus (Say), Rhagium inquisitor (Linnaeus), and Xylotrechus sagitattus sagitattus (Germar) were more abundant in understorey traps. In contrast, Ips pini (Say), Pityogenes hopkinsi Swaine, Monochamus carolinensis (Olivier), Acmaeops proteus (Kirby), and Astylopsis sexgutatta (Say) were more abundant in canopy traps. The common practice of trapping in the understorey may be optimal for sampling arboreal insects as part of survey efforts. However, additional species may be found by trapping at other vertical placements.

The following notes report the occurrence in Nova Scotia of Sthereus ptinoides (Germ.) and indicate the distribution in North America of 35 species introduced there from the Old World. Of the Old World species, ten are reported from America for the first time; previous records of two others are probably erroneous. Two, which were named and described in Rhyssemus Muls. and Scolytus Geoff. as species native to America, are considered introduced, and new synonymy is proposed for them. Confusion of introduced with native species is noted in Stethorus Weise and Rhinoncus Schön. The material recorded from Newfoundland was collected in the Northern Insect Survey, which is a co-operative project of the Canada Department of Agriculture and the Defence Research Board, Canada Department of National Defence.

The behavior, reproductive capability, and longevity of Telenomus calvus Johnson, a phoretic egg parasitoid of the spined soldier bug, Podisus maculiventris (Say), were examined in the laboratory. Telenomus calvus females were observed at 25 different locations on hosts’ bodies; preferred sites were pronota and femora. Attachment to hosts was facilitated by greatly enlarged arolia. Parasitoids dismounted from hosts at the time of oviposition to parasitize egg masses. Production of female progeny by parasitoids in phoretic association with hosts peaked on the 1st day after adult emergence, then declined steadily until day 6; male progeny production remained relatively low and constant over the same period. The mean (± SE) number of progeny produced by T. calvus females was 22.4 ± 3.0. Such a small egg complement enabled most females not in phoretic association, and presented with a fresh egg mass daily, to oviposit all or nearly all of their eggs in the first host egg mass encountered. The intrinsic rate of natural increase for T. calvus in phoretic association was estimated as 0.149 ♀ ♀−1 day−1, resulting in a doubling time of 4.65 days. Longevity on non-ovipositing females with access to honey was 33.7 ± 1.1 days, but declined sharply to 5.7 ± 0.4 days when in phoretic association with hosts. Pre-imaginal development of T. calvus was restricted to host eggs that were ≤12h old, despite continued observed oviposition attempts in older host masses. These results are discussed with regard to the biology of T. calvus as a phoretic parasitoid and to its importance as a parasitoid of P. maculiventris in Louisiana.