Onthophagus nuchicornis (Linnaeus), an accidentally introduced dung beetle, is the only scarabaeine species encountered commonly in cattle dung in British Columbia. Its dung burial efficiency and its potential for inhibiting development of coprophagous fly larvae were measured in greenhouse experiments.

The beetles buried dung most efficiently when they were present in the ratio of one pair per 40–50 g of feces. Higher or lower rates of infestation resulted in reduced burial Survival of fly larvae was inversely related to the numbers of brood balls constructed by the beetles, and hence to the amount of dung buried. Beetle activity in the field probably has little harmful effect on the dung-breeding horn fly as the beetles cease burial activity before midsummer, when horn flies reach their greatest numbers, and as they do not bury significant amounts of dung in pastures.

The desirability and possibility of introducing exotic dung beetles into British Columbia for fly control is discussed.

Ips calligraphus (Germar) has previously been recorded from Jamaica but this is the first record of Ips grandicollis (Eichhoff) in the island. In Jamaica, both bark beetles attack 5 species of Pinus, 4 of which had not been previously recorded. The beetles thrive mainly on freshly cut logs and weakened trees, but recently they have been rising to economic importance in plantations. Successful attack on live trees is enhanced by mass aggregation of dispersing adults during invasion. Some adults may re-emerge after a phase of oviposition and disperse to new food sources. There is degeneration of flight muscles during oviposition, and regeneration to allow for another dispersive flight. In I. calligraphus attacking Pinus caribaea there was a mean of 26.74 ± 6.86 (mean ± SE) eggs per gallery, while in I. grandicollis there was 19.29 ± 3.04. The proportion of females at emergence was 0.57 ± 0.03 and 0.05 ± 0.02 in I. calligraphus and I. grandicollis, respectively.

Using field and laboratory (stereoscope) observations, we investigated copulation and oviposition behaviours of Protopiophila litigata Bonduriansky, which mates and oviposits exclusively on discarded cervid antlers. Typically, a male leapt onto a female, briefly tapped the sides of her abdomen with his legs, then stimulated her abdominal tip with his tarsi, parameres, and gonopods until she extended her genitalia (~4 min), after which the pair established genital lock (~10 min). Meanwhile, the female emigrated to a part of the antler where density of single males was lower. Following sperm transfer (~87 min) and genital separation (~5 min), the female deposited and ingested two droplets containing spermatozoa (~6 min). Then she oviposited (~29 min) into cracks or pores in the antler’s surface while the male remained in tandem and pushed away single males with his wings. Males often wrestled for possession of females, but take-overs were rare. Whereas most aspects of the copulation-oviposition cycle of P. litigata are characteristic of other necrophagous or scatophagous flies, the manner in which P. litigata females expel and ingest ejaculate materials after copulation has not been reported in any other-species of Diptera.

The strong attractiveness of logs infested with female ambrosia beetles, Trypodendron lineatum (Oliv.), to the flying population was sharply reduced after the addition of males. The field response of T. lineatum was greatly reduced when air from logs infested with attractive females was mixed with air passing over logs infested with both sexes. The findings suggest that females keep producing the attracting principle in the presence of males. Males appear to reduce secondary attraction by producing a volatile substance(s) which may be anti-aggregating or repellent in its effect.

Mortality of immature Nasonia vitripennis (Walk.) was least on young house fly pupae (less than 48 hours old, at 24.5 ± 0.5 °C.) and increased with increasing host age. Increased mortality on old hosts was manifested principally as a decrease in female adult progeny, numbers of adult males and of mature diapause larvae remaining approximately constant. Reduction in the percentage of females in the adult progeny reared on old hosts probably resulted from superparasitism. This kills more female than male larvae and occurred more commonly on old hosts, each of which provides a smaller quantity of suitable food for the immature parasites. Adults reared on old hosts were smaller and relatively fewer of them were able to emerge. The proportion of the total mature parasite progeny that remained in diapause was greater on old hosts, probably because of qualitative differences in the food provided by hosts of different ages.

It has been established that a complex of predacious arthropods on apple trees in Nova Scotia can control phytophagous mite populations (Lord, 1949). Some of the predators, when sufficiently numerous, may also be important in the control of other pests such as the eye-spotted bud-moth, Spilonota ocellana (D. & S.), and the codling moth, Carpocapsa pomonella (L.). When predation has reduced the mite population to small numbers, the insect predators almost disappear from the orchard. In most orchards in this province, the use of spray materials innocuous to predators has greatly reduced the phytophagous mite populations. The low mite population is an important gain but it is not known whether the attendant small numbers of predators is advantageous in the natural control of pests in general. This will be answered in time by the experience of the growers and, meanwhile, further research is needed on the interrelations of the phytophagous and predacious species and on how they are affected by orchard practices and other factors. This involves studies on the food preferences and behaviour of many species. In addition, means must be found to modify cultural practices to make conditions as favourable as possible for certain species of predators.

The song of Metrioptera sphagnorum (F. Walker) is a prolonged trill alternating regularly between two intensities. Oscilloscope analyses reveal two stridulation modes corresponding to the two intensity levels. These two modes are described in terms of pulse structure.Characteristic frequency spectrograms are associated with each mode. In one mode audio frequencies are emphasized; the other mode is dominated by high intensity ultrasonic frequencies. At the approach of a conspecific male, singers were observed to prolong the audio-dominated stridulation mode.

The present paper is the result of a study of the food plant relationships of Exema Lac. and Arthrochlamys Ihering (Chlamys Knoch) in Canada. The study has shown that the species have strong monophagous tendencies, and that a knowledge of food plants is the key to an understanding of those which have been confused under the names Chlamys gibbosa and C. plicata.

Two large-scale forestry experiments, in Quebec (Sylviculture et aménagement forestiers écosystémique (SAFE)) and Alberta (Ecosystem Management by Emulating Natural Disturbance (EMEND)), were established in the late 1990s to test the effects of alternative silvicultural strategies (e.g., partial cutting) on biodiversity in northern boreal forests. We collected spiders in pitfall traps 2 years after the application of partial-cutting treatments in deciduous stands at EMEND and 6 years after similar treatments in deciduous stands at SAFE. Although we are aware of the challenges imposed by disparate locations and whole-scale experimental methods, our objective was to compare the effects of partial cutting on spider assemblages (diversity and community composition), and in doing so, to formulate a few general statements. Overall, 98 species (6107 individuals) were collected from Alberta and 86 species (3414 individuals) from Quebec. Of these, 44 species were common to both regions. Ordination and indicator-species analyses revealed a distinct effect of geographic separation: the spider assemblages in deciduous stands within the boreal plains ecoregion of Alberta and the boreal shield in Quebec were distinct. However, the effects of partial cutting on spider assemblages within each project were similar: removal of 25%–33% of trees shifted a characteristic old-growth fauna toward one more typical of clearcuts. Indicator-species analysis also revealed the dominance of wolf spider (Lycosidae) species in clearcuts within both experiments and we present evidence that clear-cutting homogenizes spider assemblages. Old-growth forests contain spider faunas that are easily disrupted by moderate partial cutting. In the face of intense harvesting practices, managing for the maintenance of biodiversity and conservation of spider faunas in northern forests will require retention of old-growth forests.

Several investigators have shown that the composition of insect hemolymph varies considerably between various insect species (Crescitelli and Taylor, 1935; Pratt, 1950; Auclair, 1953 and 1959; Wyatt et al., 1956; Todd, 1958). It is possible that differences in the biochemistry of insect hemolymph could affect the nutritive value of host fluids. Therefore the feeding of the females of certain hymenopterous parasites on various hosts may affect also their fecundity and thus influence the establishment of imported parasites or the maintenance of indigenous parasites in certain habitats. Scambus buolianae (Htg.), an imported external parasite of the larvae of pine shoot moth, Rhyacionia buoliana (Schiff.), and possibly of other Lepidoptera species, was used to investigate the nutritional effect of various hosts on the fecundity of the females.

Laboratory studies on the biology of the carrot weevil, Listronotus oregonensis (LeConte), were performed at 21° and 27 °C. At 21 °C females laid eggs for 88 days on carrot slices and 94 days on foliage. Egg production per female averaged 156 and 175 on slices and leaves respectively. Eggs hatched after 8.3 days incubation and the larval stage comprising four instars was completed in 19.1 days. The prepupal and pupal stages lasted 3.7 and 9.4 days respectively. The complete life cycle including an average preoviposition period of 17 days was 57.6 days. Development was more rapid at 27 °C, with the complete life cycle taking only 37 days.

The development of the Manitoba Horse Fly Trap was motivated initially by the need to control tabanid flies in spite of a lack of effective and safe insecticides. This objective could be realized only through a study of orientation behaviour in the field. Starting with the old observation that tabanids are attracted to darkcoloured objects (‘targets’), the influence of colour of target, colour of background, size, shape and movement of target were investigated. The most attractive target proved to be a glossy black (or red) sphere about 24 inches diameter, about three feet above the ground. In the course of its development the trap has provided interesting insights into visual perception of tabanids which will require physiological confirmation. The attractant principle is overwhelmingly visual. An initial surmise that thermal radiation contributes to the attraction significantly has been superseded, although a thermal stimulus may be involved in the behaviour of the flies after they reach the trap. Since only the hemato- phagous sex (females) is attracted to the trap, the behaviour involved appears to be teleologically related to host seeking activity. On arrival at the trap the insects fly in the space around the target and eventually move upward into the no-return chamber at the apex. When the trap is used for fly control the apical chamber is not needed if the interior of the trap is treated with a powerful, residual insecticide. In addition to its potential uses in conjunction with insecticides for control of tabanids, the Manitoba Horse Fly Trap can be used to study the correlation of flight activity with meteorological conditions as well as the seasonal and geographical distribution of tabanid species. The trap can be used effectively in the study of Stomoxys behaviour and control. If the sphere is replaced by a wick containing organic sulfides, blow flies can be attracted to it in considerable numbers.

Many instances of pest populations increasing following the application of pesticides to crops have been reported, with natural enemy destruction by the pesticide often cited as the cause (Putman and Heme 1959). Other explanations include a greater food supply available due to the death of competing pest species (Root and Gowan 1978), and direct stimulation of the enhanced species by sublethal doses of a pesticide, evidenced as increased fecundity (Leigh and Wynholds 1980; Boykin and Campbell 1982; Coombes 1983). In Ontario the use of the insecticide azinphosmethyl has been followed by population increases of the green peach aphid (Myzus persicae (Sulzer)) (Founk and McClanahan 1970; Ritcey et al. 1982). Our study was undertaken to determine the causes.

The biology of Cassida hemisphaerica Hbst. (Coleoptera: Chrysomelidae) is given and its suitability as a biological control agent of bladder campion, Silene cucubalus Wibel, is evaluated. Because its host range includes a number of ornamental plants in the genus Dianthus and the adults will feed on economic plants in the family Chenopodiaceae, introduction of C. hemisphaerica is not at this time justified.

A 4-year study in the virgin organic soils of southwestern Quebec revealed that most elaterid larvae moved from the subsurface to the top 10 in. of soil in early May, when the soil temperature at a depth of 4 in. was approximately 35°F. This upward movement readied its peak when the topsoil moisture content was 200% and the soil temperature at 4 in., 55°F. In early June, when the soil temperature reached 67°F, the larvae began to move downward and very few larvae were found in the first top layers of soil when the temperature was above 72°F. This downward movement lasted until the end of August and again the larvae moved up to feed near the surface of the soil until the first frost, usually recorded in mid-November. The data indicate that June to early September is generally the most favourable period for growing vegetables.

Management of Leptoglossus occidentalis Heidemann in lodgepole pine (Pinus contorta var. latifolia Engelm.) seed orchards of British Columbia, Canada, would be improved with knowledge of its damage potential at different times of the growing season. Mesh insect-exclusion bags were placed over cones, and adults or nymphs of L. occidentalis were enclosed in different bags for 9 periods of 10 to 38 days between 6 May and 17 September 2004. Feeding by adult females between 6 May and 28 May reduced total extractable seeds, a result of ovule damage before fertilization. Reduction in the number of filled seeds per cone was highest between 6 May and 29 June, with each adult female reducing yield by approximately 1.7 seeds per day. Between 29 June and 10 August, each adult female reduced the number of filled seeds per cone (seed set) by 1.0 to 1.25 per day. Seed set reduction declined to approximately 0.25 filled seeds per adult female per day after 10 August. Third to fifth instars caused seed set reduction between 0.6 and 1.2 filled seeds per cone per nymph feeding day from 29 June to 10 August. Utilizing these findings would improve management of L. occidentalis in a commercial seed orchard setting.

An investigation into the abundance of spiders in a three-acre apple orchard of northeastern Wisconsin was conducted in a natural and two artificial environments (captan and DDT) from 1959 through 1961. Six families, 17 genera and 24 species were recorded, with 15 species of hunting spiders and 9 species of cobweb forms present. Most abundant were Paraphidippus marginatus (Walck.), Philodromus cespiticolis (Walk.), Philodromus sp., Araniella displicata (Hentz) and an unidentified species of Salticidae. Comparisons are made with reports from the northeastern United States and Canada. Highest numbers were in the fungicide environment which was attributed to the more abundant and lush foliage there. Extremely low counts were obtained from the insecticide environment. Captan was deemed highly recommendable for increasing the total number of predacious spiders in an apple orchard.

Mountain pine beetle (Dendroctonus ponderosae Hopkins; Coleoptera: Curculionidae) is a major disturbance agent in pine (Pinus Linnaeus; Pinaceae) ecosystems of western North America. Adaptation to local climates has resulted in primarily univoltine generation time across a thermally diverse latitudinal gradient. We hypothesised that voltinism patterns have been shaped by selection for slower developmental rates in southern populations inhabiting warmer climates. To investigate traits responsible for latitudinal differences we measured lifestage-specific development of southern mountain pine beetle eggs, larvae, and pupae across a range of temperatures. Developmental rate curves were fit using maximum posterior likelihood estimation with a Bayesian prior to improve fit stability. When compared to previously published data for a northern population, optimal development of southern individuals occurred at higher temperatures, with higher development thresholds, as compared with northern individuals. Observed developmental rates of the southern and northern populations were similar across studied lifestages at 20 °C, and southern lifestages were generally faster at temperature extremes (10 °C, 27 °C). At 25 °C southern fourth instars were significantly slower than northern fourth instars. Our results suggest that evolved traits in the fourth instar and remaining unstudied lifestage, teneral (i.e., preemergent) adult, likely influence latitudinal differences in mountain pine beetle generation time.

A fungal outbreak of Pandora neoaphidis (Remaudière and Hennebert) Humber (Zygomycetes, Entomophthorales, Entomophthoraceae) caused maximum daily mortality of 6 and 34%, respectively, in sympatric populations of Acyrthosiphon kondoi Shinji and Acyrthosiphon pisum Harris (Homoptera, Aphididae). This epidemic suppressed the A. pisum population but not the A. kondoi population. The results suggest that low level infections in A. kondoi may greatly increase the inoculum available for transmission to the highly susceptible A. pisum.

Pea aphids, Acyrthosiphon pisum (Harris), were sampled from 1980 to 1983 in field peas, Pisum sativum (L.), in Manitoba. Sweep and foliage samples were taken in commercial fields and plots. Aphids were found in late May or early June soon after the crop emerged, but populations were low throughout June. Populations increased in July, when the crop was flowering and producing pods, and peaked in the latter half of July or early August in 3 of the 4 years, when pods were maturing. Populations decreased rapidly after the peak, as the plants senesced. In 1980, a drought year, aphid densities were low and the populations peaked in the middle of August. From 1981 to 1983, densities exceeded the economic threshold in all commercial fields and all but one of the plots that were sampled.