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 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.

Annual population estimates of spruce budworm, Choristoneura fumiferana (Clem.), larvae and the incidence of larval parasitism were monitored in northern New Brunswick following the collapse of the 1949–1959 epidemic in the region. The most common parasitoid among the very sparse hosts was Synetaeris tenuifemur, although it had been rarely found during the epidemic. Larval parasitism sometimes exceeded 50% but it could not be shown as a key factor associated with changing host abundance.

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.

Aspects of the life history of the aphid hyperparasitoid Asaphes vulgaris Walker, when reared on Aphidius nigripes Ashmead, were investigated under laboratory conditions. Longevity was significantly related to temperature and to the sex of adults. Female life span was about 4 months at 15 °C compared with 46 days at 25 °C; under the same conditions male longevity was 66 and 19 days, respectively. Females started to oviposit in aphid mummies upon eclosion and lifetime fecundity was high, reaching 1433 offspring. The sex ratio (proportion of males) was low early in reproductive life but rose sharply after several weeks. The implications of these results on the efficacy of A. nigripes in the potato agrosystem are discussed. It is suggested that high hyperparasitoid fecundity and longevity might play a role in reducing the impact of the primary parasitoid.

The spruce budworm (Choristoneura fumiferana (Clem.)) is a forest pest in all Canadian Provinces and Territories, and in the northeastern, midwest, and northwestern Unired States. It is by iar the most destructive insect affeiting the extensive balsam fir-spruce forest types in Ontario, Quebec, the Maritime Provinces, and Maine. Outbreaks of varying extent have been reported from these regions almost every year for the past half-century (deGryse, 1947). Periods in which outbreaks were particularly severe and widespread occurred from about 1909 to 1920 and in the 1940's and 1950's. In both periods, outbreaks showed a tendency to shift from west to east, intensifying first in parts of northern Ontario and Quebec and dying out in the Atlantic region south of the St. Lawrence River.

The life stages of Macroglenes penetrans (Kirby), an egg–larval parasitoid of the wheat midge, Sitodiplosis mosellana (Géhin), are described. The mean length and width, respectively, of 25 parasitoid eggs deposited in host eggs were 0.105 ± 0.008 (SD) mm and 0.041 ± 0.006 mm. Mature oocytes were 0.131 ± 0.008 mm long by 0.038 ± 0.004 mm wide, slightly larger than laid eggs.

A frequency distribution of head width (HW) indicated two larval instars during the feeding period. During development, the HW of the first instar remains almost constant at about 0.03 mm whereas body length (BL) increases from about 0.15 to about 0.3 mm. Both HW and BL increase in the second instar from about 0.15 and 0.49 to 0.34 and 1.05 mm, respectively, for mature larvae. The third instar does not feed and is characterized by hook-like "pseudomandibles" and four incurving spines on the terminal segment. The pupa is adectious exarate. Adults are about 2 mm long, shiny bluish-black, and have translucent wings. Males have prominent rust-coloured eyes; eyes of females are less prominent and fuscous.

This study characterized the spatial distribution of adult western flower thrips, Frankliniella occidentalis (Pergande) (Thysanoptera: Thripidae), released at the centres of greenhouses stocked with either cucumber (Cucumis sativus L. (Cucurbitaceae)) or chrysanthemum (Dendranthema grandiflora (Tzelev) (Asteraceae)) plants. Experiments conducted using either adults marked with fluorescent powder or unmarked adults revealed that the density of females per plant decreased as an inverse function of the distance from the release point. Inverse regression models with steep decreases in density over small distances may commonly describe the dispersal behaviour of insects that have limited flight capacity and settle on the first plants that they encounter. Females were found on plants farther from the release point as time elapsed, dispersing throughout the greenhouse at an average rate of 0.18 to 0.29 m per day. Distinct sex ratios for adults captured on sticky cards or sampled on host plants suggested that males and females exhibit different dispersal behaviours. The spatial distribution of F. occidentalis varied across generations, with females exhibiting a lower level of aggregation around the release site than their nymphal progeny. The average rate of spread between consecutive generations fluctuated between 0.05 and 0.17 m per day. Considering the limited dispersal of F. occidentalis, outbreaks may be effectively suppressed by applying insecticides or releasing natural enemies in relatively small concentric areas surrounding heavily infested plants, as well as near the edges of greenhouses.

Because laboratory and field cage experiments had shown that partially sterile (25 krad dose) male codling moths were sexually more competitive than sterile (40 krad) ones, a study was made in a British Columbia orchard in 1970 to determine whether release of 25 krad moths of mixed sexes would suppress this pest more effectively than release of 40 krad moths. Approximately 75,000 moths/ha were released from 24 April to 25 September for each dose level. In the 25 krad moth release plot, the percentage of apple fruits damaged by this pest at harvest was reduced from 0.21 in 1969 to 0.08 in 1970, whereas in the 40 krad plot damage was reduced from 0.04 in 1969 to 0.02 in 1970.

Release of 25 krad moths was also compared with insecticide sprays for codling moth suppression in two small areas at Cawston and Olalla, B.C. At Cawston, the percentage of apples damaged at harvest was reduced from 1.0 in 1969, after three sprays of phosalone, to 0.1 in 1970 after release of irradiated insects. In contrast, per cent damage in a nearby apple orchard, sprayed twice with azinphos-methyl in 1969 and 1970, increased from 2.0 in 1969 to 8.1 in 1970. At Olalla, per cent damage was about the same (0.5) in 1969, after three phosalone sprays, as in 1970 (0.6) after release of irradiated insects. In a neighboring apple orchard, sprayed twice with phosalone in 1969 and 1970, per cent damage was about the same (1.0–1.2) each year.

The biology of Telenomus chloropus Thomson was studied on eggs of Nezara viridula (L.) which had been reared on the stink bug resistant soybean, Glycine max (L.) Merrill, genotype PI 171444 and the susceptible cultivar Davis. Time of development of T. chtoropus from egg to adult emergence was not significantly different in eggs oviposited by N. viridula reared on either Davis or PI 171444. However, successful emergence of T. chloropus from host eggs was significantly lower for parasitoids that developed in eggs from N. viridula reared on PI 171444. Longevity of adult T. chloropus was not significantly different between females that were allowed or denied oviposition regardless of the genotype fed the host. Total fecundity of T. chloropus reared from eggs of N. viridula fed PI 171444 was one-half that of parasitoids from the Davis treatment. Although ovipositional patterns over the lifetime of parasitoids from the 2 treatments were similar, the mean number of progeny produced per day was significantly greater in the Davis treatment. Also, the ovipositional period of parasitoids from the PI 171444 treatment was shorter than for parasitoids from the Davis treatment.

Four species of Orius Wolff, a Holarctic genus, are known from the Nearctic region. Orius insidiosus (Say) is known from midwestern and eastern United States and eastern Canada, while O. tristicolor (White), shown here to be a valid species, is transcontinental in North America. O. minutus (L.), a common species in the Palaearctic region, is known from western North America. O. pumilio (Champ.) occurs in Florida. The distinguishing characteristics of the species are given, and a key is provided.

Aedes japonicus japonicus (Theobald) (Diptera: Culicidae), the Asian bush mosquito, is a keen biter linked to the transmission to humans of a variety of diseases. It has moved significantly from its historical Asian distribution, with its arrival in North America first noted in 1998 in New York and New Jersey, United States of America. Here we report the presence of A. j. japonicus within our collections of mosquitoes in the capital city of the easternmost province in Canada: St. John’s, Newfoundland and Labrador, in 2013. This observation provides further evidence of this mosquito’s ability to significantly expand its geographic range, potentially affecting connectivity between subpopulations globally.

A well-accepted function of courtship in sexually dimorphic and cannibalistic spiders is suppression of female predatory responses. We quantitatively analysed courtship in the western black widow, Latrodectus hesperus Chamberlin and Ivie (Araneae: Theridiidae), to determine the behavioural elements of the males’ courtship that are correlated with mating success and/or the females’ responses. The 58% of males that engaged in web reduction elicited fewer aggressive responses from females and induced female quiescence more quickly than did males not exhibiting web reduction behaviour. Our data suggest that web reduction by male L. hesperus functions in sexual communication, a context not previously explored.

The brown marmorated stink bug (BMSB), Halyomorpha halys (Stål) (Hemiptera: Pentatomidae) is non-native species that has rapidly expanded its range in the United States of America and Canada. This study was aimed at increasing our knowledge of the biology of BMSB and developing a rearing method. A laboratory culture maintained on 15 different foods (pear, peach, Granny Smith apple, red delicious apple, squash, tomato, carrot, green bean, grape, corn, leaves of princess tree, leaves of butterfly-bush, dry seeds of sunflower, cowpea, and peanut) had on average 26.0±2.1 eggs per egg mass, and an incubation period averaging 6.94±1.2 days. Developmental duration from second instar to adult averaged 28.2±0.9 days similar to second instars reared to adult on single diet of green beans, corn, sunflower, cowpea, and peanut seeds. Survival from egg to adult was 85.4% and a growth index (GI) of 2.2±0.2 for the laboratory culture comparable to ⩾2.0 GI and 80–90% reported nymphal development on a diet of dry sunflower, cowpea, and peanut seeds. We reared six generations of BMSB before the study was terminated. Our results indicate the foods that are better for BMSB growth, development, and survival.

Cultural practices (tillage, planting date) were examined for their effect on flea beetle, Phyllotreta cruciferae (Goeze), populations in three species of oilseed crucifers—Brassica napus L., B. rapa L., and Crambe abyssinica Hochst. No-till appeared to reduce flea beetle densities when compared with conventional tillage. The greater structural diversity of the no-till plots might be interfering with host plant location. Earlier plantings had significantly more flea beetles per plant than later plantings. The Brassica crops yielded higher densities of beetles compared with crambe, supporting earlier reports of crambe resistance.

Infections of Nosema pyrausta (Paillot 1927) Kotlan 1928, in egg masses of Ostrinia nubilalis (Hübner) used to artificially infest maize did not significantly decrease the ability of the infected larvae to migrate to adjacent plants. When 25% of the egg masses placed on the plants contained N. pyrausta, the resulting larvae had an incidence and an intensity of infection significantly greater than those of the controls. If 100, 75, 50, and 25% of the infesting eggs were infected by N. pyrausta, the number of larvae per plant were reduced by 72.0, 44.0, 29.3, and 38.7% respectively. N. pyrausta was transmitted via contaminated frass. The result was a reduction in populations of O. nubilalis larvae.

Two geographical biotypes (G and A) of Heliothis zea Boddie were identified in a constant temperature laboratory study. The G (Georgia) biotype was found to have a mean development rate 5 ± 1% faster and coefficient of variability 44 ± 9% higher than the comparable A (Arizona) biotype. Each geographical biotype was described by a biophysically based, nonlinear development function with an R2 equal to 0.995. At temperature ranging from 15.6° to 35.6°C, the adult emergence distributions transformed to a physiological age scale were shown statistically to be independent of temperature. They could be described by a “same shape” distribution function. The empirical same shape distribution for rate was not significantly different from a hypothetical normal distribution.

Puparia of Delia radicum collected in late autumn at Winnipeg and Portage la Prairie (Manitoba), St-Jean-sur-Richelieu (Quebec), London (Ontario), and St. John’s (Newfoundland) were parasitized mainly by Aleochara bilineata (Gyllenhal) (Coleoptera: Staphylinidae) and Trybliographa rapae (Westwood) (Hymenoptera: Cynipidae). At Winnipeg, St-Jean, and St. John’s parasitism by A. bilineata was high (<94%) and by T. rapae was low (<3%). At London, both parasitoids attacked less than 14% of the host puparia. At Winnipeg, host population density was related to parasitism by A. bilineata and to the temperature and rainfall during June and July. Parasitism by A. bilineata may be related to cumulative degree-days over 5°C during June and July at Winnipeg and during June and September at London. In Canada, the parasitoid complex is not effectively stabilizing host population density. The introduction of additional parasitoid species should be considered.

This is the second in a series of papers on the taxonomy of the cocoons and puparia, cast larval skins, and other remains of parasitic Hymenoptera and Diptera that are found in or near the remains of parasitized hosts after the parasites have emerged. The structures of taxonomic significance in the separation of the species were described and discussed in a previous paper (Finlayson, 1960). The present paper deals with the known Canadian parasites of the European spruce sawfly, Diprion hercyniae (Htg.). Parasites of D. hercyniae that were dealt with in the previous paper are not described or illustrated here.

There is increasing evidence that short-range reproductive behaviors of phytophagous pentatomid bugs are mediated by vibrational signals. These signals have not yet been examined for bugs in the genus Euschistus, which contains several species native to the Americas. Substrate-borne vibrational signals (songs) were recorded from both sexes of the Consperse stink bug, Euschistus conspersus Uhler, an economically important agricultural pest in western North America. Females produced two songs (FS-1 and FS-2), each consisting of a series of frequency-modulated pulses with a pulse duration of 352 ± 105 (mean ± SD) and 163 ± 36 ms, respectively. Males produced four distinct songs, two composed of frequency-modulated pulses (MS-1 and MS-3), one consisting of narrowband pulses (MS-2), and one composed of a series of 1–6 short pulses, many of which were fused to form distinct pulse trains (MS-4). For both males and females, songs consisting of very short, frequency-modulated pulses (FS-2 and MS-3), with a mean pulse duration <170 ms, were emitted when the other member of the pair was silent. Songs made up of longer, frequency-modulated pulses (FS-1 and MS-1) were produced spontaneously and in response to songs from conspecifics. Pulses of MS-2 were produced by a male once a duet with a female had been initiated. This song had no frequency modulation and a longer mean pulse repetition time than MS-1. The two female songs and three of the male songs (MS-1, MS-2, and MS-3) were produced during the calling phase of mating behavior. Pulse trains of MS-4 were emitted during close-range courtship. During copulation males produced intermittent pulses of MS-1, the function of which is unknown. Dominant frequencies of all songs ranged from 102 to 136 Hz, comparable with those of other pentatomid songs. Although there were superficial similarities in the song structures of E. conspersus when compared with those of other pentatomid species, the song repertoire of E. conspersus was distinct and unique.