Thelytokous reproduction was developed and fixed in arrhenotokous Muscidifurax raptor Girault and Sanders by mating hybrid females, of interhemispheric strains, with naturally occurring males of M. uniraptor Kogan and Legner. A change in ovipositional behavior was shown by these mated hybrid females which subsequently produced thelytokous Fx offspring for 10 generations. Sperm depletion and extranuclear factors are considered.

Leptoglossus occidentalis Heidemann (Hemiptera: Coreidae) is considered to be an important cone and seed pest in seed orchards in British Columbia; however, no impact studies have been done in Canada. Surveys to determine the distribution of L. occidentalis were conducted over a 3-year period in three coastal seed orchards of Douglas-fir, Pseudotsuga menziesii (Mirb.) Franco, and over a 2-year period in two seed orchards of lodgepole pine, Pinus contorta var. latifolia Engelmann. Leptoglossus occidentalis was found to distribute itself in patches, coinciding with a clonal preference. Seed losses were assessed for 2 years in the coastal Douglas-fir orchards and for 1 year in one lodgepole pine orchard. The percentages of partially filled seed that could have been caused by feeding of L. occidentalis or by a number of other factors were < 5% in coastal Douglas-fir for both 1992 and 1993 and ~14% in lodgepole pine in 1993. Apparently because populations of L. occidentalis were low, there was no correlation between the percentage of partially filled seed and number of insects per tree. Except in unusual circumstances, management measures in Canada are judged not to be necessary as populations of L. occidentalis are consistently below the calculated threshold levels required to cause ≥5% loss in seed production.

Six species of oribatid mites (Acari: Ceratozetidae) in six genera were recorded from a variety of arboreal habitats in western Canada, including the canopy of temperate rainforest, montane forest, and the leaves of shrubs. Four of these species are new to science and are described: Sphaerozetes winchesterisp.nov., on the basis of adults; and Dentizetes ledensissp.nov., Melanozetes crossleyisp.nov., and Neogymnobates marilynaesp.nov., on the basis of adults and immatures. Jugatala tuberosa Ewing is redescribed from both adults and immatures, a new observation being that adults have seven pairs of notogastral porose areas. The placement of the genus Jugatala Ewing in Ceratozetidae is confirmed. Latilamellobates baloghi (Mahunka) is newly recorded from North America, and the taxonomy of the genus is discussed. The major differences among these six species are presented in tabular format.

Three western species of tussock moths of the genus Orgyia are all susceptible to infection by the same two nuclear polyhedrosis viruses. An eastern species of Orgyia is also affected by these viruses. In the Western States, the natural occurrence of the two viruses appears to be limited to definite geographic areas. Infectivity of the viruses for hosts outside the genus Orgyia is not known. One report of such cross-infectivity could not be substantiated. Bodies which appear to be composed of viral materials but which are not normal virus particles are sometimes found occluded in polyhedra.

The identity of Leucopis (Leucopis) argenticollis Zetterstedt, an adelgid predator described from Sweden, is established and a lectotype is designated for it; L. orbitalis Malloch, described from Illinois is placed as a synonym of it. Another species (predator of the mealy plum aphid) that was formerly confused with argenticollis, is described as Leucopis (Leucopis) conciliata McAlpine and Tanasijtshuk, new species. Both species are shown to be holarctic and are treated from the standpoints of adult and larval morphology, biology, and distribution. The paper contains 33 figures.

Dimilin® 1-(4-chlorophenyl)-3-(2,6-difluorobenzoyl)-urea is an insect growth regulator which disrupts the insect's molting process. It has been field tested against eastern spruce budworm, Choristoneura fumiferana, with variable results (Dimond 1975; Retnakaran et al. 1976). In addition to fluctuations in many field parameters, innate variations in susceptibility to Dimilin during different stadia may influence efficacy. Retnakaran and Smith (1976) found that larvae during the 5th and 6th stadia were most susceptible.

Ten new species of Trichobius are described from the Neotropical Region: T. intermedius (Dominican Republic, Haiti, Bahama Islands, Cuba, Jamaica, Puerto Rico, Virgin Islands, Lesser Antilles, Mexico, Guatemala, Honduras, and El Salvador); T. neotropicus (Dominican Republic); T. cognatus (Dominica and Cuba); T. wenzeli (Cuba); T. dusbabeki (Cuba); T. cernyi (Cuba); T. frequens (Cuba, Dominican Republic, and Jamaica); T. macroti (Cuba and Bahama Islands); T. robynae (Puerto Rico); and T. dominicanus (Dominican Republic).

The Tachinidae of America north of Mexico have undergone extensive changes in nomenclature since the last catalogue was produced in 1965. Many of these changes were published in the Tachinidae chapter of Manual of Nearctic Diptera, but few of the changes in that work were explicitly stated and none was recorded in Zoological Record. These changes, which included a new genus, new records for America north of Mexico, new generic synonymies, and hundreds of new combinations (including extralimital species), are documented here. This paper also includes more than 30 nomenclatural changes proposed as new herein by the junior author (primarily for America north of Mexico), representing new generic and specific synonymies and new combinations. A new record for America north of Mexico is reported.

Continuous colonies of Chironomus riparius Meigen can be conveniently maintained in the laboratory and the swarming and mating behaviour is readily observable. Swarming is eocrepuscular and is mediated, at least in part, by light intensity and the marker stimulus. The effects of sound and volatile chemicals on the initiation and maintenance of swarming are not clearly apparent, but there is some evidence to suggest that pheromones may play a role in swarm cohesion.

The present study was undertaken to determine the influence of some major constituents of plant essential oils on the toxicity and fate of thymol, a phenolic monoterpene from garden thyme (Thymus vulgaris L.) (Lamiaceae), following topical administration to the cabbage looper, Trichoplusia ni (Hubner) (Lepidoptera: Noctuidae). Tested individually, trans-anethole (LD50 = 71.2 µg/larva) and methyl salicylate (93.6 µg/larva) were the most toxic, whereas phenylethyl propionate (555.8 µg/larva) and mineral oil (2279.3 µg/larva) were the least toxic. However, when coadministered, mineral oil was the most synergistic (synergy ratio, SR = 25). A proprietary blend of essential oils (A4 Blend) was strongly synergistic (SR = 9), as was trans-anethole (SR = 5), while the majority of the other compounds tested yielded SRs of 2–3. Based on experiments using tritiated thymol as a radiotracer, the fate of this plant toxin within 60 min of topical administration varied widely with the essential oil carrier. Some carriers facilitated rapid disappearance of thymol from the insects' integument and rapid appearance internally, whereas others prolonged the tenure of thymol on the integument and delayed entry into the insect. The highest internal levels of radioactivity were observed when phenylethyl propionate was the carrier (47% of the topical dose), the lowest when rosemary oil was the carrier (9%). The highest proportion of the dose was excreted when eugenol was the carrier (20% of the topical dose), the lowest when mineral oil was the carrier (4%). Overall, there are no apparent trends linking the fate of thymol in the different carrier oils to the synergies observed or to the relative polarities of the carriers.

The larch sawfly, Pristiphora erichsonii (Htg.), like the European spruce sawfly, Diprion (Gilpinia) hercyniae (Htg.), is an obligatoty parthenogenetic ‘species’, that is, it is endowed with the capacity of reproducing without recourse to mating. Wlde this absence of cross-fertilization with the attendant uniformity of progeny it assures renders such species ideally suited for experiments requiring the use of controls, it would at first sight appear ro preclude the adoption of conventional genetic procedures in studying them, other than by circuitous means: it is the main purpose of this contribution to suggest a possible means of circumventing the difficulty.

Lowbush blueberry (Vaccinium angustifolium Aiton (Ericaceae)) production is highly dependent on insect pollination to maximise yields. The current losses in honey bee (Apis mellifera Linnaeus (Hymenoptera: Apidae)) colonies pose a serious threat to the blueberry industry, raising interest in alternative pollinators. Abundance and diversity of native pollinators usually decreases with distance from natural habitats. In this study, we evaluated the effects of distance from wooded habitats such as windbreaks and forest borders on the presence of native pollinators in blueberry fields in Lac-St-Jean (Québec, Canada). Four treatments were compared: single-row, double-row, natural windbreaks, and forest borders. Pan-traps were placed at 5, 30, and 60 m from the windbreak or forest border. A total of 3878 native pollinators were collected and 81% were ground-nesting bees. The forest border was the only treatment with higher abundance and species richness on the periphery (5 m) of the field than at further distances, supporting the hypothesis that the presence of pollinators is favoured by habitats potentially offering more abundant and diverse nutritional resources. Our overall results reveal that native pollinators are distributed quite homogeneously in blueberry fields, suggesting that windbreaks are beneficial to native pollinator communities.

Eastern larch beetles, Dendroctonus simplex LeConte (Coleoptera: Curculionidae: Scolytinae), are monophagous, phloem-feeding herbivores of eastern larch (tamarack), Larix laricina (Du Roi) Koch (Pinaceae). Recently dead or moribund trees are preferentially colonised. Outbreaks of eastern larch beetles are generally localised and short-lived, although a large outbreak has been occurring in the Great Lakes region of North America since 2000. The beetle is reported as univoltine, with a single, spring-emergent, reproductive parent generation establishing one to three sibling broods per year. Some progeny emerging during summer or fall re-enter the tree bole close to ground level to overwinter, while remaining brood adults overwinter within pupal chambers in situ. Owing to these behaviours, eastern larch beetles have been suggested to possess an obligate overwintering reproductive diapause. However, studies have not confirmed this hypothesis. We tested the reproductive viability of non-overwintered progeny in three laboratory experiments. Non-overwintered progeny were reproductively viable, suggesting that a portion of the population may exhibit a facultative adult overwintering diapause. Progeny that emerged naturally from the host (i.e., putative fall-emergers) demonstrated reproductive rates almost six-fold those of manually extracted insects demonstrating a propensity to remain in situ (i.e., putative spring-emergers). These results shed new light onto the reproductive behaviour of eastern larch beetles, and suggest that future population dynamics may be influenced by a warming climate.

Extensive investigations on the biology and control of biting flies were conducted in northern Canada from 1947 to 1953 (Brown, et al., 1951; Haufe, 1952; Hocking et al., 1950; Twinn et al., 1948, 1950; Twinn 1950). The difficulty of assessing populations of mosquitoes both in chemical control and in ecological investigations limited the interpretation of some of the work that was undertaken. One of the primary objectives of ecological and behaviour studies was to determine the weather conditions that are favourable for attraction of mosquitoes to man. Reliable estimates of the unattracted population must, for this purpose, be obtained independently of the observer. Large catches are alsoimportant in estimating abundance when the time for individual catches is reduced to one hour or less. For these reasons a satisfactory mechanically-operated device for sampling mosquitoes in flight became essential.

In 2002, two types of light traps were compared against sticky yellow cards for efficiency and selectivity in capturing adult swede midge Contarinia nasturtii (Kieffer) (Diptera: Cecidomyiidae). Incandescent light traps were more efficient at capturing swede midge than were sticky traps. Incandescent light traps were more selective than blacklight traps and required less time for processing of samples and identification of captured midges. Emergence (2003 and 2004) and pheromone (2004) traps were used to assess swede midge population dynamics. Captures from emergence traps indicate up to five overlapping emergence events for swede midge each year. Emergence traps captured swede midge earlier in the season than pheromone traps, but pheromone-trap captures continued later in the season than those in emergence traps. Pheromone traps are small and portable, easy to maintain, and capture significantly more swede midge than emergence traps.

Ips concinnus (Mannerheim) and Ips mexicanus (Hopkins) comprise Group I of the genus Ips DeGeer (Coleoptera: Scolytidae). Members of this group have 3 spines on each lateral margin of the declivity and strongly arcuate sutures on the anterior face of the antennal club. I. radiatae Hopkins is placed as a synonym of I. mexicanus (Hopkins). I. concinnus breeds in Picea sitchensis in the coastal region from Alaska to southern Oregon. I. mexicanus breeds in various species of pines from Alaska to Guatemala and eastward in the United States and Canada to the Rocky Mountains. A key to the species and descriptions are provided.

A specially constructed fence was developed to exclude cabbage flies, Delia radicum (L.), from plantings of rutabaga. The number of first-flight female D. radicum caught on traps inside fenced enclosures declined linearly with fence height from 0 to 90 cm. Females caught in plots surrounded by a 90 cm high fence were 80.6 and 82.8% fewer than in open check plots in 1991 and 1992, respectively. The percentage of transplanted rutabagas killed by cabbage maggot in the 90 cm high enclosures was 1.4% in 1991 and 25.5% in 1992, compared with 11.8 and 84.5% in the open check plots, respectively. The mean damage index rating for rutabagas was severe in the open check plots but slight in the 90 cm high enclosures in 1991. Only 1.2% of rutabagas in the open check plots would have been of marketable grade in 1991, compared with 54% in the 90-cm enclosures. The mean damage rating was highest in the open check plots in 1992, but damage was also severe in all fenced plots due to the heavy infestation levels that year. The potential of exclusion fences for use in pest-management programs for rutabagas and other brassica crops is discussed.

Within the family Cerambycidae (Coleoptera), (E)-6,10-dimethyl-5,9-undecadien-2-ol (fuscumol) and (E)-6,10-dimethyl-5,9-undecadien-2-yl acetate (fuscumol acetate) have been shown to attract several species in the subfamily Lamiinae. However, it is not yet clear whether beetles within the subfamily actually produce these compounds as pheromones or rather respond to them as kairomones. We report here that male Astyleiopus variegatus (Haldeman) produce both fuscumol and fuscumol acetate, suggesting that the compounds are indeed pheromones for this species. We also determined that the absolute configurations of these compounds are (S)-fuscumol and (S)-fuscumol acetate by synthesis of both enantiomers of each.

A study was conducted to examine the springtime hatching characteristics of Melanoplus sanguinipes (F.) and Aulocara elliotti (Thomas) eggs on rangeland. Laboratory experiments showed that eggs of M. sanguinipes required fewer accumulated degree days (DD) to complete post-diapause development than those of A. elliotti at a constant temperature of 23.3°C. Springtime field observations revealed that A. elliotti nymphs emerged prior to or concurrent with M. sanguinipes. Additionally, results suggest that A. elliotti nymphs emerge over a shorter interval than M. sanguinipes. Much of the variation in springtime emergence could be attributed to species-specific oviposition sites, pod depth, and pod orientation that resulted in A. elliotti eggs accumulating heat more rapidly than M. sanguinipes eggs. Results help explain some of the variation found in egg hatching of these two grasshopper species on rangeland.

One very extraordinary phase in the development of certain polyembryonic encyrtids is the production of a precocious larval form. This anomaly appears while its normal sibs are still in an early embryonic stage of development, and although it leads an active parasitic life within the host it never succeeds in developing beyond the larval stage.