Several resistant lines of wheat, Triticum aestivum (L.) (Poaceae), have been developed to control populations of the Russian wheat aphid, Diuraphis noxia (Mordvilko) (Hemiptera: Aphididae). We examined the potential effects of D. noxia resistant lines on another aphid, the bird cherry-oat aphid (Rhopalosiphum padi (L.) (Hemiptera: Aphididae)), which commonly co-occurs with D. noxia. Because one type of resistance (mediated by the Dn1 gene) is purported to be induced rather than constitutive, we also determined the degree to which the suitability of resistant and susceptible plants is modified by previous infestation. Although resistant lines were derived from five different sources, we did not detect any differences in the population growth of R. padi on resistant and near-isogenic susceptible plants. The performance of D. noxia was reduced as expected on resistant plants but was unaffected by whether or not plants had been previously infested. In contrast, the performance of R. padi was reduced on plants that had been previously infested but was unaffected by whether plants were resistant or susceptible to D. noxia. Because neither species' performance was especially low on previously infested, resistant plants, there was no evidence that prior aphid feeding induces a higher level of resistance.

Cereal leaf beetle, Oulema melanopus L., is an invasive pest insect of small grain cereal crops, particularly oat, wheat, and barley. The first report of cereal leaf beetle populations in North America came from Michigan in 1962. Surveys indicate that populations have become established throughout eastern North America from Ontario to Alabama and in northwestern North America from Utah to southern British Columbia. The establishment of O. melanopus in western North America has raised concern that its presence is a potential risk to the Canadian cereal industry, especially in the prairie ecozone of western Canada, where up to 10 million hectares of cereal crops are grown annually. Field surveys to date have indicated that O. melanopus has not yet become established in this region. A CLIMEX™ model for O. melanopus in North America was developed, based on climate and ecological parameters, and validated with actual distribution records. The actual distribution of O. melanopus in eastern North America matched the predicted distribution well. The model predicts that, once introduced, O. melanopus would readily survive in the cereal-growing areas of western Canada and present a significant risk to cereal production. The potential for establishment of O. melanopus in the prairie ecozone of western Canada substantiates the efforts by regulatory agencies to prevent accidental introduction of this pest species.

The body sizes of mature larvae and adults from field and laboratory populations of the wheat midge, Sitodiplosis mosellana (Géhin) (Diptera: Cecidomyiidae), were measured to determine possible causes of variation in size and consequences of such variation through the life history. Mature larvae varied eightfold in mass. Female larvae were 80% heavier than males, on average. Variation in mass was associated with both the position of larvae on a wheat spike and the number feeding together on a developing seed. Larvae were 9% smaller when they developed on smaller, later developing seeds and 15%–18% smaller when they competed with five other larvae on an average-sized seed. Fewer small larvae survived winter. Larval density per infested seed increased with number of larvae per spike, suggesting that larval size may have density-dependent population effects. Small larvae produced few adults of Macroglenes penetrans (Kirby) (Hymenoptera: Pteromalidae), an egg parasitoid that overwinters as a larva in the third larval instar of S. mosellana. These effects were probably due to size, but sex may also have been a factor. The size of adults, measured by wing and abdomen length, was also variable, although less so than the size of larvae. Adult size was not associated with time of emergence and both large and small females dispersed, but female fecundity (4–105 mature eggs per individual) increased with body size.

A hypothetical parasitoid mass rearing facility is used to unite principles from behavioral ecology and biological control. The key to the problem is variation in the tendency of solitary parasitoids to superparasitize. Superparasitism affects individual and population parasitoid productivity, though not necessarily to the same degree. Herein, the interest is in determining conditions that will maximize parasitoid population productivity when superparasitism varies. To accomplish this, a combination of graphical marginal analysis (to provide an economic context), dynamic optimization models (to determine individual parasitoid superparasitism tendency), and functional response models (to determine parasitoid population productivity) has been used. Marginal analysis shows that marginal returns decrease with an increase in the number of parasitoids released but that the slope of the marginal returns curve depends upon the sensitivity of superparasitism to environmental conditions. In addition, results show that parasitoid responses can be highly nonlinear and, as such, can greatly affect optimal numbers of parasitoids released in a nonintuitive manner. This behavioral ecology approach greatly increases efficiency and predictability of parasitoid production.

Ammonia has long been known to be an attractant for the apple maggot, Rhagoletis pomonella (Walsh) (Diptera: Tephritidae) (Hodson 1943, 1948). The responses of apple maggot to ammonia release rates, however, have not been adequately determined. Ammonia release rates determined from mass losses of ammonium carbonate, ammonium acetate, and casein hydrolysate lures (e.g., Jones 1988; Reynolds and Prokopy 1997) do not take into account decomposition and release of compounds such as carbon dioxide or volatiles that may be moderately repellent (Bateman and Morton 1981; Mazor et al. 1987) or attractive to some Tephritidae flies (Mazor et al. 1987). In this study, the objectives were to determine the responses of apple maggot females and males in western Washington to ammonium hydroxide lures designed to release a wide range of ammonia. An emphasis was placed on identifying the ammonia release rates that elicit maximum fly responses.

The biology and phenology of the yew big bud mite, Cecidophyopsis psilaspis (Nalepa, 1893), were studied on Pacific yew, Taxus brevifolia Nutt., in British Columbia, Canada. The mite showed the typical life cycle of eriophyoids on evergreen hosts, with all stases being present throughout the year. The numbers of C. psilaspis, which colonized both vegetative and reproductive buds, peaked in May to August, with the lowest numbers in March and October and the highest numbers in June. Mite numbers differed among bud types, with averages following the sequence terminal buds = lateral buds > male reproductive buds > axillary buds > female reproductive buds > latent buds. Very few mites were found in latent buds except during bud formation, when other vegetative buds were unavailable. Reproductive buds were colonized mostly from May to July. There was no evidence of arrhenotoky in C. psilaspis, as the proportion of mites that were females ranged from 54% to 100%. Temperature and predation were considered the likely factors that determine population fluctuations. It was hypothesized that C. psilaspis abundance increased following favorable spring temperatures and new food resources, whereas predation by other mite species and lower temperatures, which prolonged development, were responsible for the low numbers in March and October.

We assessed bee diversity and abundance in urban areas of Vancouver, British Columbia, Canada, to determine how urban environments can support bees. Habitats examined were community and botanical gardens, urban wild areas, Naturescape flower beds and backyards, and traditional flower beds and backyards. A total of 56 bee species (Hymenoptera), including species of the genera Andrena Fabr. (Andrenidae), Bombus Latr. (Apidae), Osmia Panzer and Megachile Latr. (Megachilidae), and Halictus Latr. and Dialictus Pauly (Halictidae), were collected. Abundance exhibited strong seasonal variation. Wild bees were most abundant during late spring, whereas honey bees peaked at the end of the summer. The most abundant species seen was the managed honey bee Apis mellifera L. (Apidae), followed by wild Bombus flavifrons Cresson. Community and botanical gardens, and plants such as cotoneaster (Cotoneaster Medik. sp.) and blackberry (Rubus discolor Weihe & Nees) (Rosaceae), centaurea (Centaurea L. sp.; Asteraceae), buttercup (Ranunculus L. sp.; Ranunculaceae), and foxglove (Digitalis L. sp.; Scrophulariaceae), had the highest abundance of bees, while bee populations in wild areas were the most diverse. Weeds such as dandelions (Taraxacum officinale G.H. Weber ex Wiggers; Asteraceae) dominated these wild areas and had one of the highest diversities of bee visitors. Traditional flower beds with tulips (Tulipa L. sp.; Liliaceae) and petunias (Petunia Juss. sp.; Solanaceae) had relatively poor diversity and abundance of bees throughout the year. Our study suggests that urban areas have the potential to be important pollinator reservoirs, especially if both bloom and habitat heterogeneity are maintained and enhanced through sustainable urban planning.

Aphids were sampled in commercial blueberry, Vaccinium corymbosum L. (Ericaceae), fields in southwestern British Columbia, Canada, from 2001 through 2003. Ericaphis fimbriata (Richards), the dominant aphid, overwintered as eggs on blueberry and emerged in late February and March during bud break. Apterous adult fundatrices were found during April. The fundatrices produced both alate and apterous virginoparae. There was a positive curvilinear relationship between production of alatae and aphid density on flower clusters, but not on leaf terminals. Peak densities in late June or early July varied from 300 to 9000 aphids per plant in different fields, suggesting that there may be considerable variation in Blueberry scorch virus transmission rates among fields infected with the virus. Production of alate virginoparae (percentage of all fourth-instar aphids with wing pads) declined from May through August. Sexual morphs were produced in late September and October. The efficacy of postbloom insecticide applications in June, by growers, was variable. Experimental trials showed that dormant oil is not effective in preventing aphid emergence. Aphids on blueberry should be controlled before bloom, before alatae are produced and large populations occur, but the efficacy of this approach in reducing virus transmission needs to be tested.

Insect aggregation pheromones are defined as chemical substances produced by members of one or both sexes that induce members of both sexes to form aggregations (Borden 1984). Aggregation pheromones are typically emitted by and attract adult insects. Interestingly, larvae of the codling moth, Cydia pomonella L. (Lepidoptera: Olethreutidae), seeking pupation sites will aggregate in response to pheromone produced by cocoon-spinning conspecific larvae (Duthie et al. 2003). Such aggregations may be part of a mating strategy in which protandrous males are arrested by sex pheromone emanating from mature female pupae, thus allowing mating to ensue as soon as a female moth ecloses (Duthie et al. 2003). The cocoon-derived pheromone also attracts the specialist prepupal parasitoid Mastrus ridibundus Gravenhorst (Hymenoptera: Ichneumonidae), which “eavesdrops” on pheromonal communication of cocoon-spinning larvae (Jumean et al. 2004).

Ever since its entry from New York State in the late 1960s, the gypsy moth, Lymantria dispar (L.) (Lepidoptera: Lymantriidae), has continued to expand its distribution in Ontario to the north and west (Nealis and Erb 1993). Outbreaks were recorded for the first time in the Sudbury – North Bay region in the early 1990s, by which time there was evidence of resident populations extending along the north shore of Lake Huron as far west as Lake Superior. The population expansion along the north shore is characterized by a patchy occurrence of small outbreaks, which typically last for a few years and then disappear (Annual Forest Health Reports, Great Lakes Forestry Centre, http://www.glfc.cfs.nrcan.gc.ca/foresthealth/index_e.html). Nealis et al. (1999) found that winter weather, parasitoids, and the gypsy-moth-specific fungal pathogen Entomophaga maimaiga Humber, Shimazu et Soper (Zygomycetes: Entomophthorales) were the most prominent sources of mortality in those transient outbreaks.

Pissodes yunnanensis Langor et Zhang, a pest of Yunnan pine, Pinus yunnanensis Franchet, in southwestern China, occurs at elevations of 2200–2800 m. These weevils infest Yunnan pine trees less than 20 years old but prefer trees 8–10 years old. Oviposition occurs mainly along the upper trunk on current-year and 1-year-old growth and occasionally on the upper lateral branches. Weevil feeding often kills the leader, which results in stem forking and crooking. At times, after 2–3 years of consecutive severe infestation, tree mortality occurs. In southwestern Yunnan Province, adults of this univoltine weevil emerge from infested stems from mid-April to mid-July. Eggs appear in late June, first-instar larvae in early July, and fourth-instar larvae in late March of the next year. First- and second-instar larvae feed in the phloem, and third-instar larvae move to the sapwood or pith, where they overwinter. In March, larvae resume feeding and development. Fourth-instar larvae excavate pupal chambers (chip cocoons) in the outer sapwood or pith, and pupation occurs from late March to late May. Optimal development of eggs and pupae occurs at 25 °C in the laboratory. Parasitism is the main cause of mortality in P. yunnanensis, accounting for 2%–25% of mortality among third- and fourth-instar larvae and 5%–10% among pupae.

Exotic leafmining sawflies (Hymenoptera: Tenthredinidae) on birch (Betula spp., Betulaceae) have become widely distributed in Canada since their introduction to eastern North America in the last century (Digweed et al. 1997). However, their distributions north of the 60th parallel are poorly known (Digweed et al. 2003). No birch leafmining sawflies were detected at Hay River and Louise Falls, Northwest Territories (NT), in 1993, but the ambermarked birch leafminer, Profenusa thomsoni (Konow), was reported from Yellowknife, NT, in 1994 (Digweed et al. 1997). Since that time, P. thomsoni populations have reached epidemic levels on urban birches in Yellowknife and Hay River, NT (unpublished data). While examining infested birches in Hay River in 2003, the authors also found the European alder leafminer, Fenusa dohrnii (Tischbein), attacking alder (Alnus spp., Betulaceae).

A new standard pupation shelter for sampling hemlock looper (Lambdina fiscellaria) pupae is described and compared with the burlap band method developed by Otvos (1974; The Canadian Entomologist106: 329–31). The new pupation shelter is placed on the bole, at breast height or in the crown, to estimate population abundance and mortality. The utilization of two shelters at breast height was as efficient as the use of burlap bands to estimate hemlock looper abundance and more efficient for sampling braconid cocoons. It provided reliable estimates of braconid and tachinid parasitism but overestimated that by ichneumonids. This new pupation shelter is an inexpensive tool that can be used easily by nonspecialized personnel, thus allowing increases in the number of sample plots, which is necessary to improve detection of outbreaks of the hemlock looper. This new shelter could be used to sample other lepidopterans whose late-instar larvae aggregate in concealed pupation sites.

In 1999, the leaf roller Caloptilia fraxinella (Ely) (Lepidoptera: Gracillariidae) was noticed for the first time in the city of Edmonton, Alberta, Canada, on ornamental green ash (Fraxinus pennsylvanica Marsh. var. subintegerrima (Vahl) Fern.) and black ash (F. nigra Marsh.) (Oleaceae). It has since been found there on Manchurian ash (F. mandshurica Rupr.) and white ash (F. americana L.). Specimens were collected and reared, and vouchers have been deposited in the Canadian Forest Service Arthropod Collection in Edmonton and the Canadian National Collection of Insects (CNC) in Ottawa, Ontario.

For many years, trap nests have been used to study hole-nesting bees and wasps (aculeate Hymenoptera) and to monitor their diversity and abundance (Krombein 1967; Danks 1971; Godfrey and Hilton 1983; Frankie et al. 1998). Trap nests are valuable for environmental assessment (Tscharntke et al. 1998) and for agriculture through improved pollination by bees (Bosch 1994; Stubbs et al. 1997; Hallett 2001) and biological control by wasps (Harris 1994). Frankie et al. (1988) indicated that shaded environments might be preferred habitats for some solitary bees that use tree holes for nesting. Shading could offer protection from natural enemies as well as wind, rain, and sunlight, resulting in stabilized humidity and temperature. As far as we are aware, ours is the first experimental study to consider the effect of shading of trap nests.

Two newly identified geographic isolates of a nucleopolyhedrovirus (LdMNPV-H and LdMNPV-J) were evaluated against Disparvirus (LdMNPV-D), a baculovirus insecticide registered in Canada for the control of gypsy moth (Lymantria dispar (L.) (Lepidoptera: Lymantriidae)). Profiles of HindIII and EcoRI restriction enzyme digests of viral DNA from the three viral isolates are presented. Viral isolates were bioassayed using an inoculated diet plug method to determine the dose- and time-responses of second-instar larvae of both the European and Asian strains of gypsy moth. LdMNPV-D was found to be the most virulent isolate when tested against the European strain of gypsy moth, yielding an LD50 and an LD95 (estimates of the doses required to kill 50% and 95% of the test larvae, respectively) of 95 and 774 occlusion bodies (OBs), respectively. LdMNPV-H was the most virulent isolate when tested against the Asian strain, yielding an LD50 and an LD95 of 648 and 8540 OBs, respectively. Time-response data indicate that the three isolates differ little with respect to their speed of kill (ST50; estimate of the length of time required to kill 50% of the test insects) of either larval strain. These results indicate that both new isolates (LdMNPV-H and LdMNPV-J) should be investigated further for control of the Asian strain of the gypsy moth but not pursued for control of the European strain.

Nymphs of many species of the order Odonata are easy to maintain in the laboratory, and there are hundreds of published studies dealing with behaviour, ecology, development, taxonomy, etc. that involve maintenance of nymphs under laboratory conditions. Most of these studies call for nymphs to be fed live prey, and in some cases it is possible to collect suitable prey from the field. However, in cases in which the experimental designs call for controlled diets, or in cases in which natural food is difficult to collect, as during winter months in temperate latitudes, it is common for researchers to feed nymphs with prey cultured in the laboratory. Researchers have used a variety of different prey but Daphnia sp. is one of the most popular. We have used Daphnia sp. cultures but have encountered difficulties in rearing sufficient numbers for use in experiments involving hundreds of nymphs; also, we have had the unfortunate experience of having our cultures collapse for unknown reasons at critical times of experiments.