In the early 1930's defoliation of red oak, Quercus rubra L., white elm, Ulmus americana L., apple, Malus spp., and other deciduous trees in the South Shore region of Nova Scotia was attributed to the fall cankerworm, Alsophila pometaria (Harr.), and the spring cankerworm, Paleacrita vernata (Peck). The identity of the latter was questioned when adults occurred in the fall. These adults were sutbsequently identified as Operophtera brumata (L.), the winter moth (Hawboldt and Cuming, 1950; Smith, 1950).

Access to drinking water increased the longevity of Coccinella trifasciata perplexa Muls. by about 35%. The water content of field-collected insects was 70% and of laboratory-fed insects 64%. Rate of loss of water increased, and longevity decreased when protein was absent from the food.

Anatis mali Auct. lived more than 1000 days and Coleomegilla maculata lengi Timberlake lived more than 400 days when fed on various synthetic foods. Seven of 13 species tested kid eggs when fed on these foods. A diet containing desiccated liver was the best non-prey food supplement for reproduction, and adults of three generations of C. maculata were kept on this food.

A. mali preferred dry powdered pea aphids, Acyrthosiphon pisum (Harr.), to either bean aphids. Aphis fabae Scop., or corn aphids, Rhopalosiphum maidis (Fitch), whereas C. maculata preferred corn pollen to aphids and A. pisum and R. maidis to A. fabae. Previous feeding did not affect the preference of either A. mali or C. maculata for dry aphids or pollen. C. maculata produced six eggs per mg. of food while feeding on A. pisum and four on R. maidis. Young adults ate more than older adults.

The rate of food intake was highest in A. mali during the first two weeks and in C. maculata during the first eight days after emergence. The living weight and dry weight of feeding C. maculata adults increased for eight days and then did not vary, whereas the water content decreased in this period. The index of relative growth was about 0.10 mg. per day per mg. of adult weight and food efficiency was about 0.18 mg. per mg. of food.

During the past 25 years the wheat stem sawfly, Cephus cinctus Nort., has become one of the most destructive pests of wheat in the Prairie Provinces. Annual losses in the wheat-growing area of Saskatchewan have been estimated as high as 17 million bushels (King and McDonald, 1944). There are, however, several native parasites of this pest, and of these Bracon cephi (Gahan) [Microbracon cephi Gahan] is the most important. In some areas this parasite has been very effective in reducing severe sawfly infestations.

Leaf and bark volatiles from non-host birches, Betula pendula Roth. and Betula pubescens Ehrh. (Betulaceae), and aspen, Populus tremula L. (Salicaceae), were tested on spring-dispersing Tomicus piniperda (L.) and Tomicus minor (Hart.) by gas chromatographic – electroantennographic detection (GC–EAD) and by attractant-baited traps in southern Sweden. GC–EAD analysis of the head-space volatiles from fresh bark chips of B. pendula revealed two green leaf alcohols, 1-hexanol and (Z)-3-hexen-1-ol, that consistently elicited antennal responses by T. piniperda and T. minor. Further analyses with synthetic mixtures showed that the antennae of these two Tomicus species also responded to other green leaf alcohols, such as (E)-2-hexen-1-ol found from the non-host leaves, and C8-alcohols, 3-octanol and 1-octen-3-ol, from bark of non-host birches and aspen. No antennal responses of the Tomicus species were observed to green leaf C6-aldehydes and C6-acetate or to non-host bark volatiles like trans-conophthorin, benzaldehyde, salicylaldehyde, and benzyl alcohol. In field trapping experiments, blends of electrophysiologically active green leaf alcohols or C8-alcohols resulted in reductions (> 60%) in the number of T. piniperda captured compared with that for the kairomone-baited trap. When these two blends were combined, trap catch was further reduced (90%), which was not significantly different from that for the blank control. Neither the blend of two green leaf aldehydes plus the acetate nor the bark compounds trans-conophthorin or benzyl alcohol reduced trap catches. Tomicus minor had a response pattern similar to that of T. piniperda. Hylurgops palliatus (Gyll.) (Coleoptera: Scolytidae) was attracted to the combination of kairomone and verbenone but not to kairomone and was not affected by the blends of green leaf volatiles. Our results suggest that selected leaf–bark C6-alcohols and the bark C8-alcohols may have potential in developing semiochemical-based management programs against both pine shoot beetles by repelling them from suitable breeding and feeding sites.

Ingestion of 0.1 μg of RH-5992, tebufenozide, by early 6th instar larvae of the spruce budworm, Choristoneura fumiferana (Clem.), prior to the appearance of the ecdysone peak in the hemolymph, resulted in the induction of a precocious incomplete moult that was lethal. The larvae stopped feeding within 8 h post ingestion and remained quiescent just as they do in preparation for a normal moult. Head capsule slippage started at 12 h post ingestion, became pronounced by 24 h, and by 48 h an untanned new head capsule was visible behind the old one. The lack of tanning of the new cuticle was due to the failure of dopadecarboxylase gene expression. Although the old cuticle was loose around the entire body, indicating that apolysis had occurred, there was no evidence of ecdysis of the old cuticle, suggesting that eclosion hormone was probably not released. Earlier instars required a lower dose than the later ones to elicit an "all or none" type of moulting response. The most effective routes of entry were by intrahemocoelic injection, followed by ingestion. Topical application was effective only when nonaqueous carriers such as acetone or dimethyl sulfoxide were used. The larvae were unable to discriminate between treated and untreated diet over a 48-h period. The transcription factor, Choristoneura hormone receptor 3, which is normally expressed at the onset of the hemolymph ecdysone peak, was expressed in the epidermis 1 h post ingestion of RH-5992, reached a peak level by 3 h, and became undetectable by 24 h, confirming that this analogue acts through the ecdysone receptor system. Greenhouse tests using potted white spruce trees sprayed with RH-5992 and colonized with 4th-instar spruce budworm indicated that field dosages of 35, 70, 140, and 280 g/ha would all be effective. Ground spray trials conducted in a spruce budworm infested white spruce stand in Zee Casault, Gaspé, Quebec, using a backpack sprayer showed that ≥ 70 g/ha of RH-5992 reduced the insect population by 100% with very little defoliation and was better than Chlorfluazuron® (an analogue of the chitin synthesis inhibitor, diflubenzuron or Dimilin®) treatment, which was used as a positive control. The unique mode of action of this ecdysone agonist and its effectiveness as an environmentally benign control agent for the spruce budworm are discussed.

The genus Ips is one of four closely related genera in the tribe Ipini, sub-tribe Ipina (De Geer 1775, Balachowsky 1949, Nunberg 1954, Hopping 1963). There are now 32 species of Ips recognized in North America, with a few more as yet undescribed. This paper defines the groups of closely related species with observations on the group relationships of species from other parts of the world. Work is in progress to define the North American species in each group.

Spruce budworm larvae were bioassayed against Bacillus thuringiensis Berliner to study the effect of temperature on the expression of toxicity. Temperatures between 16 and 28°C did not affect the ultimate level of toxicity (LC50). However, LT50’s increased from 2–8 days at 28°C to 11–20 days at 16°C, depending on concentration of the pathogen. When larvae were force-fed with a single dose, temperature had a similar effect on the time course of mortality without affecting the level of mortality. Feeding inhibition of force-fed larvae commenced immediately after dosing. Larvae that did not recover died without further feeding, even at lower temperatures when death occurred 2–3 weeks after dosing. Recovering larvae resumed feeding after 2 (28°C) to 6 (13°C) days. Recovered larvae took longer to develop and produced lighter pupae than untreated larvae. Our data suggest that temperature-dependent feeding and recovery did not contribute to quicker death at higher temperatures. Expression of the toxin itself appears to depend on temperature, possibly through the influence of temperature on metabolic rate of affected gut cells. Implications of these findings for the efficacy of spruce budworm control operations are discussed.

Since 1950 the University of California has maintained a program designed to evaluate the effectiveness of certain insect parasites in the control of the western grape leaf skeletonizer, Harrisina brillians B. & McD., in San Diego County, California. During this time, all sustained efforts to produce parasites in quantities for field release have failed because of recurrent outbreaks of a disease of theskeletonizer larvae. The causative agent of this disease was identified by Steinhaus and Hughes (1952) as a granulosis virus.

Scolytids were collected from snowfields above timberline in Oregon and Washington. The most productive location was Collier Glacier on Middle Sister Mountain, Ore., where 334 specimens representing 20 species were collected on 4 August 1968. Collections from seven mountains comprised 476 specimens, 12 genera, and 26 species. Hylastes nigrinus (Mann.) made up 63% of the specimens collected. The collections demonstrated that bark beetles had been dispersed vertically and horizontally thousands of feet from the nearest possible source. Phloeosinus chamberlini Blkm. was found 15 miles from the closest known host tree. Behavioral and meteorological factors involved in the dispersal of scolytids to snowfields are known only circumstantially. Certain species are thought to fly skyward initially. Some individuals presumably are carried aloft by warm updrafts and their fallout occurs when the air becomes too cool for flight.

Low seed set is a serious problem in seed orchards of lodgepole pine (Pinus contorta var. latifolia Engelmann) in the southern interior of British Columbia. We tested the hypothesis that Leptoglossus occidentalis Heidemann is responsible for the low seed set. Cones enclosed in insect exclusion bags as part of a pollination experiment produced significantly more filled seeds per cone than cones that were not bagged. In a separate bagging experiment, cones that were enclosed with a L. occidentalis female and her progeny produced only about one filled seed per cone, compared with about 28 seeds in bagged control cones. Changes in microclimate associated with the use of bags did not appear to be responsible for the observed increase in seed set in bagged cones. Leptoglossus occidentalis was also excluded from trees using the insecticide fenvalerate. Cones on fenvalerate-treated trees produced > 11 filled seeds per cone, whereas water-treated (control) cones produced < 1.7 filled seeds. These data suggest that L. occidentalis should be considered a serious pest in lodgepole pine seed orchards.

The sexes of all but three of the North American species of Ips DeGeer can be separated reliably using characters on the frons, vertex of the head, protibiae, or declivital armature. In general, these secondary sexual characters are consistent within Hopping’s species groups.

The twolined chestnut borer, Agrilus bilineatus (Weber) (Coleoptera: Buprestidae), is associated with mortality of stressed oaks in the eastern deciduous forests of North America. Beetles were attracted to stressed trees within hours of the onset of stress. We hypothesized that adult beetles rapidly locate suitable hosts by olfactory detection of tree-released volatiles. Trees with sticky-band traps and vane traps baited with crude steam distillates from inner bark of stressed white oaks, or with combinations of ethanol and oak volatiles, captured significantly more beetles than did water controls. Ethanol alone did not attract significant numbers of A. bilineatus. Eighty-two percent of beetles captured were females. Ethanol-baited traps captured large numbers of Cerambycidae, Scolytidae, and a few Cleridae, and these insects were not attracted to oak volatiles. Sticky-band traps were more effective than vane traps in capturing A. bilineatus and other Buprestidae, but Cerambycidae and Scolytidae were more effectively captured in vane traps. Our results show that A. bilineatus is attracted to oak volatiles but later successional beetles are attracted to ethanol.

Adding queen mandibular pheromone into honey bee colonies earlier than 24 h after queen loss resulted in an inhibition of queen-rearing, but not when added after 4 days. The number of queen cells initiated in each treatment decreased with the addition of the pheromone, although there were no effects on the number of queen cells torn down following pheromone treatment. The effect of adding the pheromone to queenless colonies given newly hatched female larvae under different regimens of queen cell provisioning and cell structure also was investigated. Only colonies in which larvae were presented in unmodified worker comb exhibited significantly lower rates of queen-rearing. Results indicate that queen mandibular pheromone inhibits the initiation of queen-rearing but not the maintenance of established cells.

The existence of a chemical female sex pheromone in the Oriental fruit moth has been demonstrated; it both attracts and sexually excites adult males. Males without antennae are neither attracted to, nor sexually stimulated by, the pheromone. Thus, the pheromone appears to be essential for reproduction. Active pheromone can be extracted with benzene from the tips of virgin female abdomens and bioassayed with males. The gland believed to produce the pheromone was located and examined histologically. It is now possible to investigate the chemical nature of the pheromone and its possible use in the control of the Oriental fruit moth.

The preference of the predatory midge, Feltiella acarisuga (Vallot), for adult male and female twospotted spider mite, Tetranychus urticae Koch, was examined using functional response models. The midge exhibited a type-II functional response to each prey. Handling time was estimated to be much higher for the female mites than for the males (1.52 vs. 0.40 h). Estimated instantaneous search rates for the female and male mites were similar (1.32 vs. 1.28). A preference index of 1.03 was calculated using the ratio of the instantaneous search rates. Feltiella acarisuga was found to exhibit no preference for either female or male mites; when both prey were present in equal numbers, midge larvae killed as many females as males.

Rove beetle assemblages from forest dominated by yellow birch (Betula alleghaniensis Britt. (Betulaceae)) at two sites in southeastern Quebec were characterized in terms of composition, diversity, and relative abundance. In total, 143 species were collected over two seasons (June–August of 1999 and 2000). In the pretreatment year (1999), 88 species were found in uncut stands. In the post-treatment year, 116 species were found in treated (by patch harvesting and ground scarification) and control plots combined. Sixty-one species were common to the two sites, 27 species captured in the 1999 season were not recaptured in the 2000 season, and 55 additional species were captured in 2000. There are 23 new distribution records for Quebec, and one species, Atheta (Dimetrota) pseudomodesta Klimaszewski, sp. nov., is described. New bionomics data on relative abundance, seasonality, and the utility of different trapping methods are presented. Assemblage composition is compared with that of a red spruce (Picea rubens Sarg. (Pinaceae)) forest in New Brunswick.

Larvae of the hemlock looper, Lambdina fiscellaria fiscellaria (Guenée) (Lepidoptere: Geometridae), consume both new and old foliage within the crowns of their host, balsam fir, Abies balsamea (L.) Miller (Pinaceae), despite the poor nutritional quality generally ascribed to old tissues. Laboratory studies evaluated whether the consumption of old foliage by hemlock looper larvae could be an adaptation to the relative paucity of new versus old foliage, and to the limited temporal window during which young foliage remains high in nutritional quality. Access to new foliage was critical to hemlock looper survival; 55% of larvae fed an exclusive diet of new foliage survived, whereas only 5% and 0% of larvae fed exclusively 1-or 2-year-old foliage survived, respectively. Moreover, larvae reared on branches in synchrony with bud flush were more than twice as likely to survive than those whose emergence was delayed by 2 weeks. Despite the reliance by the hemlock looper upon new foliage for survival, larvae given access to both new and old foliage survived better and were heavier than those restricted to new foliage. By incorporating older foliage into their diet, the hemlock looper can circumvent the limited availability of new foliage, thereby gaining access to more abundant tissues.

The effects of the major factors on populations of the wheat stem sawfly, Cephus cinctus Norton, were studied in the field at Lethbridge, Alberta between 1970 and 1977. Fecundity of the females, which contain an average of 32.7 eggs, is influenced by the condition and variety of host plants in which they develop as larvae. Populations of the adults that emerge from infested crops cut 7–9% by the larvae in one year may infest 70–80% of the stems of adjacent crops in the following year. Increased adult densities, however, fail to increase markedly the percentage of stems infested because the adults concentrate at field margins when they reinfest the most preferred stems. Because only one larva can mature in each stem, competition within stems that receive more than one egg causes a major drop in the population but not in the percentage of infested stems cut. Another major drop is caused by host plant resistance, which is influenced in both susceptible and resistant wheats by the weather during the growing season. On an average, all of the larvae die in 28% of the infested stems of two susceptible wheats and in 67% of those of a resistant wheat. The mortality in resistant wheats, however, is generally not sufficient to prevent economic infestations in subsequent years. Parasitism, which was a major factor in only 7 of 36 years in southern Alberta, is increased by weather conditions that cause delayed ripening of the wheat crops. The mortality of mature larvae and pupae averaged 21.3%. It is affected by extremes of moisture and temperature and can be increased slightly by shallow tillage of infested stubble.

Studies of Quaternary age Coleoptera fossils from North America and Europe plus recent analyses of insect fossils from late Tertiary (Miocene and Pliocene) sites in northern Canada, Alaska, and eastern Siberia show that many of the species composing the present Canadian insect fauna probably evolved during the Tertiary. Thus the history of Tertiary land bridge links between North American and adjacent continents is pertinent for a discussion of the present Canadian insect fauna.

Movement of lithosphere plates has contributed directly to the emergence and foundering of Tertiary land bridges in three key areas: Beringia, the North Atlantic, and Middle America.

A land bridge probably connected Siberia and Alaska in the Beringian region for most of the Tertiary. During the Eocene its climate was such as to allow exchange of tropical to subtropical adapted plants and animals. Paleobotanical evidence suggests that the Beringian area never supported the type of mixed-mesophytic forests called for by the Arcto-Tertiary concept. By the mid-Miocene much of the region north of 65° was probably a rich coniferous forest. Lowland tundra undoubtedly exited on the fringes of Beringia as early as the Pliocene.

Two and possibly three land bridges connected Greenland and Northern Europe during the Tertiary. The DeGeer bridge joined northern Greenland and Norway prior to the opening of the Greenland Sea in the late Eocene – Early Oligocene. The Greenland-Faeroes bridge was never more than a causeway along the route of the submerged ridge now occupied by Iceland. However it persisted longer, possibly existing as a chain of islands as late as the Miocene. A third land bridge may have connected Labrador and Rockall Bank near England during the Paleocene and early Eocene. The climatic history of the North Atlantic region is poorly known, but apparently sites as far north as Ellesmere Island were warm enough during the Paleocene to support subtropical to warm temperate mammalian faunas.

For most of the Tertiary the middle American region remained isolated from South America. Changes in movements of several lithosphere plates created conditions appropriate for north-south island dispersal as early as the Miocene but a true land connection, the existing isthmus, did not form until the Pliocene. Paleontological evidence suggests that tropical conditions were not prevalent there until after that event.

Observations on the biology of Trybliographa rapae (Westw.) were made as part of a general study, in Canada and Europe, of the biotic factors acting against the maggots of Hylemya brassicae (Bouché), H. floralis (Fall.) [H. crucifera Huck.], and H. cilicrura (Rond.) that attack cruciferous crops. During the study many thousands of host insects from both Canada and Europe were examined and large numbers of both hosts and parasites were reared in the laboratory.