Megarhyssa atrata F., the largest hymenopteran parasitoid known, is found in the holarctic. The stylus of its ovipositor can reach a length of 142 mm, the longest of all known genitalia in Arthropoda. This pimpline parasitizes its host, Tremex columba L., at a great depth in wood. Valvulae 3, which are always shorter than the stylus, are characterized on their outer side by abundant trichoid sensilla of three different types, and on their inner side by a dense layer of cuticular spines probably used in cleaning and shielding the stylus while at rest. The joint region between stylus and abdominal segments is richly equipped with mechanoreceptive trichoid and campaniform sensilla. The ovipositor canal is located between the two valvulae 1 which are separate for their entire length and supported proximally by the two valvulae 2 which are joined to each other from the base. The distal end of the stylus, shaped like an indented lancet, has secretory pores, the first such to be observed in Hymenoptera, from which accessory gland secretions flow. These secretions reach the end of the stylus by intravalvular canals in valvulae 1 and 2. These substances, which may cause cell lysis and also act as lubricants, can accumulate among the tens of thousands of cuticular formations distributed along the stylus which are thought to be surface storage cavities for the secretions. The sensory equipment of the stylus consists of six rows of approximately 200 mechanoreceptive campaniform sensilla. The ovipositor of M. atrata is thus characterized by almost exclusively mechanoreceptive sensory equipment; chemical stimuli appear to be monitored by two types of trichoid sensilla on valvulae 3. The finding that secretory pores occupy exactly the same sites as chemoreceptors in Ichneumonidae, Chalcidoidea, and Proctotrupoidea demonstrates the importance of studying the ovipositor of this parasitoid adapted to withstanding extreme pressures as it penetrates deep into wood.

The effect of light intensity and wind speed on the body temperature of larvae and adults of the Colorado potato beetle (Leptinotarsa decemlineata (Say)) was studied in the laboratory. At a light intensity of 0.95 kW m−2 and without wind, the body temperature of larvae and adults was respectively 9.3 and 18.2 °C higher than air temperature. The temperature difference between the body temperature of larvae and adults and the air temperature increased linearly with an increase in light intensity. Wind speed had an important effect on the rate of increase of the body temperature as a function of light intensity in both larvae and adults. Our results demonstrated that the energy balance of larvae and adults differs.

Two naturalized populations and two planted populations of Rosa rugosa Thunb. were studied with respect to chalcid seed wasp infestation. Megastigmus nigrovariegatus Ashmead was found in hips from planted R. rugosa in Halifax and Dartmouth, Nova Scotia, but not from bushes at naturalized sites. The percentage of infested hips at the Halifax and Dartmouth locations was 26 and 31%, respectively. The percentage of infested achenes within a single hip varied widely from 3 to 79% at the Halifax site and 7 to 60% at the Dartmouth site.Adult emergence was over 75% successful when achenes were over 2 mm in diameter but less than 15% for smaller achenes. The exit hole on the achene faced the outer wall of the hip. Adults emerged later in Nova Scotia than in the United States and between 59 and 72% were female. More than one adult wasp was observed ovipositing on a single hip.

Emergence, oviposition, and seasonal flight activity of adult, speckled green fruit worm, Orthosia hibisci Guenée (Lepidoptera: Noctuidae), were monitored during 1991 and 1992 in a mixed block of McIntosh and Spartan apple trees at Summerland, British Columbia, to establish relationships between the phenology of these events and degree-days (DD). Using air temperatures and a developmental threshold of 3 °C, median emergence of males was predicted most accurately (0–2 days) by starting DD summations on 1 March. Median emergence of females was predicted without error when first catch of a male in a trap baited with sex attractant was used as a population reference point (biofix) to start DD summation. Using a threshold temperature of 3 °C, observed cumulative emergence of females reached 50% at 63.5 ± 4.05 DD3 °C after biofix, similar to the laboratory-derived prediction of 61.3 ± 4.2 DD with a threshold temperature of 2.8 °C. Catches of males with sex attractant preceded oviposition, but female catches in light traps lagged behind oviposition, suggesting older females were being caught in light traps. The oviposition curve was linear and parallel to the cumulative curve of male catches with sex attractant. Oviposition began at 26.7 DD3 °C and reached 50% at 94.2 DD3 °C after biofix, respectively. Weibull equations fitted to observed cumulative catches with sex attractant, female emergence, and oviposition, combined with laboratory-derived DD models of egg and larval development, were used to predict phenology of O. hibisci and correlate it with flowering phenology of pome fruits. This study provides a basis for timing application of selective insecticides against O. hibisci based on first catch in a sex-attractant trap and DD summations.

We designed a simple device for physically restraining live Diptera for measurement and marking. This new technique does not involve powders, anaesthetics, or handling with fingers or forceps, and can be adapted for use with flies of any size. We tested it on acalyptrate flies of 1.5–3.0 mm body length, and were able to sex, measure, and mark them with individual codes (enamel paint applied to the thoracic notum) in 5–7 min per fly, with a 96% success rate. This technique may be applicable to a range of behavioural and ecological research.

Among the 20 geometrid species recovered from annual surveys in coniferous forests in the Swiss Alps, three species, Epirrita autumnata (Borkhausen), Agriopis aurantiaria Hübner, and Poecilopsis isabellae Harrison, were identified as sources for parasitoids that might be suitable as candidates for introduction to Newfoundland to control the eastern hemlock looper, Lambdina fiscellaria fiscellaria (Guenée). Four univoltine Hymenoptera were identified as candidates: Dusona contumax (Forster) (Ichneumonidae) from A. aurantiaria, Dusona sp. from P. isabellae, Aleiodes cf. gastritor (Thunberg) (Braconidae) from E. autumnata, and Aleiodes. sp. from P. isabellae. The candidate parasitoids were confined with their native hosts in the laboratory and observations made to gather basic biological information and define protocols for screening.

Small numbers of these parasitoids were shipped to Newfoundland and screened in the laboratory against hemlock looper larvae. Although attacks by D. contumax, Dusona sp., and A. cf. gastritor were observed, parasitoid development did not occur. All parasitoid eggs recovered from the hemlock looper larvae attacked were encapsulated. Dusona contumax, Dusona sp. from P. isabellae, A. cf. gastritor, and Aleoides sp. from P. isabellae are not recommended for introduction against the eastern hemlock looper.

Female gypsy moth, Lymantria dispar (L.), exhibited a distinct calling rhythm at 17 °C, with peak calling ca. 4.0 h before the beginning of scotophase and minimal calling at or near the onset of the photophase (4.0 h). The rhythm persisted under continuous darkness (DD) and is thus circadian. The duration of calling in DD was shorter than that under a 16 h L: 8 h D photoperiodic regime. In contrast, under continuous light (LL) females called continuously and no overt rhythm was observed. Individuals kept under LL from the beginning of the pupal stage exhibited a distinct calling rhythm following a transfer to DD. The influence of temperature on the calling rhythm of L. dispar differed from most other species of moths studied to date. At lower temperature the onset of calling occurred later than at higher temperatures. The duration of the calling period increased from 11.1 h at 9 °C to continuous calling at 35 °C. The responses of females to temperature changes made at different times during the calling period suggest that the timing of calling in L. dispar does not depend on absolute temperature level.

The oviposition preferences of Lygus lineolaris (Palisot de Beauvois) were studied on Brassica carinata A. Braun, Brassica juncea (L.) Czern, Brassica napus L., Brassica rapa L., Sinapis alba L. (high glucosinolates), Sinapis alba L. (low glucosinolates), and Sinapis arvensis L. in a choice test during a 14-day period in field cages. Host-plant discrimination occurred on at least two levels. The first level occurred at the generic level; ovipositing females first selected species of Sinapis on which to lay eggs and later laid on species of Brassica. On species of Sinapis, 80% or more of the total number of eggs were laid during days 1–6, whereas only 35–58% were laid during this period on species of Brassica. The second level occurred at the species level in both Brassica and Sinapis. In Brassica, significantly more eggs were laid on B. carinata and B. napus than on B. juncea; in Sinapis, significantly more eggs were laid on S. alba (high glucosinolates) than on S. arvensis. The numbers of eggs did not differ significantly among B. carinata, B. napus, and S. alba (high glucosinolates). The numbers of eggs on B. rapa and S. alba (low glucosinolate) were not significantly different from those on the other five Brassica and Sinapis hosts tested. Host-plant selection seemed to be unaffected by glucosinolate levels in the seed of S. alba.

Black flies (Diptera: Simuliidae) were collected from a tamarack stand, Larix laricina (Du Roi) Koch, heavily infested with Adelges lariciatus (Patch) (Homoptera: Adelgidae). Insect nets were used to sweep the tamarack branches to capture black flies associated with the trees. Six black fly species were sweep-netted, with 85.5% of all flies belonging to Simulium venustum Say complex. Samples of honeydew and the crops and midguts of individual black flies were tested by thin layer chromatography using fructose, glucose, sucrose, turanose, melezitose, raffinose, and stachyose as standards. The sugars fructose, glucose, sucrose, raffinose, and stachyose were found in the adelgid honeydew samples. Of the 201 black flies tested, 194 contained sugars, which occurred in 16 combinations. It is argued that stachyose can be used to indicate when black flies have fed on the adelgid honeydew. We conclude that 49.7% of the S. venustum collected from the tamarack had fed recently on this honeydew source. In addition, it was observed that black flies reared in the laboratory readily ingested freshly excreted and older (dry) honeydew when presented with branches from the tamarack stand.

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.

Cryptolestes ferrugineus (Stephens), Cryptolestes pusillus (Schönherr), Tribolium castaneum (Herbst), and Rhyzopertha dominica (Fabricius) were gradually exposed to falling temperatures in the laboratory, simulating conditions in the centre of a 12- or 6-m-diameter granary containing wheat. Two years of overwintering mortality for C. ferrugineus and R. dominica were obtained from 11–13 farm granaries (40–100 t wheat). Cryptolestes ferrugineus (adults) was the most cold hardy species among the beetles tested. In the laboratory, survival was 40% at 25 °C declining to 10 °C over10 months, whereas at 25 °C declining to 0 °C over 10 months survival was 7%. Cryptolestes pusillus and T. castaneum did not survive once temperatures were below 10 °C, and R. dominica adults did not survive temperatures below 3 °C. In the field, there was no survival of C. ferrugineus in granaries that had February temperatures of −6.7 °C or lower. Six-week exposure to −10 °C killed most C. ferrugineus adults taken from granaries in February. Cryptolestes ferrugineus caught in granaries were more cold hardy than laboratory-reared strains. No T. castaneum or R. dominica survived an entire winter in granaries in the 2 years tested. Although C. pusillus was not tested in the granaries, it is unlikely it could survive the winter, as it had the same level of cold tolerance as T. castaneum in the laboratory. The implications for the population dynamics of these pest species in prairie grain are discussed.

An extract from seeds of the neem tree, Azadirachta indica A. Juss, enriched with azadirachtin, was evaluated in three experiments for control of the spruce aphid, Elatobium abietinum (Walker), on potted spruce trees in a greenhouse. The extract in Exps. 1 and 2 was first applied in February 1993 when spruce aphid populations were initially low; populations were observed weekly for 15 weeks. In Exp. 1, foliar applications to the runoff point of 150 ppm azadirachtin applied three times (biweekly) held populations below 5.3 aphids per 6-cm twig samples; populations on trees treated at 75 ppm, or with emulsifier only, reached 32.2 and 26.9 aphids per sample, respectively. With five weekly applications (Exp. 2), suppression to < 14 aphids per sample was achieved with both 150- and 75-ppm treatments; populations on control trees peaked at 36.8 aphids per sample. The extract at 150 ppm in Exp. 3 significantly reduced the number of aphids on trees that initially had high populations. The results indicate that neem has potential for operational use against aphids in conifer seed orchards.

Resistance was documented in 1995 to commonly used organophosphorus, carbamate, and pyrethroid insecticides in populations of western flower thrips, Frankliniella occidentalis (Pergande), from six commercial greenhouses in Ontario. Adult female thrips were placed in glass vials treated with technical-grade insecticides and mortality at 18 h was compared with a single discriminating concentration, the computed LC99 of a reference laboratory population. Baseline dose–response regressions for insecticides commonly used in Ontario greenhouses were obtained for the laboratory population of western flower thrips. The organophosphorus compounds chlorpyrifos and malathion and the carbamates methomyl and bendiocarb were the most toxic materials tested; whereas the pyrethroid deltamethrin and a phosphoroamidate acephate were the least toxic. The addition of piperonyl butoxide to solutions of deltamethrin was highly synergistic. The mixture of deltamethrin and endosulfan (1:1) was moderately synergistic. Populations of western flower thrips from commercial greenhouses were resistant to deltamethrin, but deltamethrin mixed with piperonyl butoxide or endosulfan was synergistic in all cases. None of the populations were resistant to all of the insecticides tested. Recommendations are presented for the development of a resistance-management strategy for western flower thrips.

In a laboratory experiment on the decision rule underlying the avoidance of flower revisitation by foraging bumble bees (Bombus impatiens), artificial flowers were arranged in two rows. For each flower visited, the choice was either to travel straight ahead onto a flower in the same row or to change direction and choose a flower in the other row. The distance between rows was manipulated to be smaller than, equal to, or greater than the distance between flowers in the same row. When the distances between adjacent flowers within a row and between rows were equal, a significant tendency to travel straight ahead was observed. This tendency was sensitive to changes in distance between rows, even when the distances between rows far exceeded the distance between flowers within a row. The tendency was abolished when the distance between rows was smaller than the distance between flowers within a row. A significant alternation of the bumble bee between rows (zigzag path) was observed in only one condition: when not only the distance between rows was much smaller than the distance between flowers in the same row, but also when the rows were staggered such that the bee could alternate between rows while still travelling in an almost straight line. These results show that the two variables of distance and angle are integrated, and that the choices made by bumble bees do not reflect a simple rule. Future research on tradeoffs is suggested.

Experiments conducted in a plantation of oil palms, Elaeis guineensis (Jacquin), infested with bagworms, Metisa plana (Walker), tested the hypotheses that crowding enhances the incidence of larval ballooning and negatively affects the size attained by pupae. Proportions of ballooning larvae increased with increasing densities of larvae per palm. The lengths of bags (and pupal cases) decreased with increasing numbers of bagworms per leaf. Ballooning of larvae from crowded palms is likely adaptive because individuals attaining large size at pupation have proportionately greatest survival, mating success, and fecundity.

Timema bartmani sp.nov. is described from San Bernardino County, California. Both sexes are known. Males show relationship with Timema podura Strohecker. Females closely resemble Timema tahoe Vickery. Timema bartmani may be the sexual ancestor of the parthenogenetic T. tahoe.

In 1994 and 1995 insects were collected from several sites in southern Manitoba, where purple loosestrife, Lythrum salicaria L., is dominant. Collection techniques included the use of trap plants, sweep netting, vacuum sampling, and hand collecting. Insects from 38 families were collected and grouped into four general feeding guilds: herbivores, predators, omnivores, and fungivores. Herbivores that directly fed on L. salicaria included Galerucella nymphaeae Linné (Coleoptera: Chrysomelidae), Myzus lythri (Schrank) (Homoptera: Aphididae), Poecilocapsus lineatus (Fabricius) (Hemiptera: Miridae), Kleidocerys resedae (Panzer) (Hemiptera: Lygaeidae), Ametastegia glabrata (Fallén) (Hymenoptera: Tenthredinidae), Orgyia leucostigma (Smith) (Lepidoptera: Lymantriidae), Lophocampa maculata (Harris) (Lepidoptera: Lymantriidae), Spilosoma virginica (Fabricius) (Lepidoptera: Arctiidae), Simyra henrici (Grote) (Lepidoptera: Noctuidae), Dichomeris ligulella (Hübner) (Lepidoptera: Gelechiidae), Melanchrapicta (Harris) (Lepidoptera: Noctuidae), Hyles galli (Rottenburg) (Lepidoptera: Sphingidae), and Biston betularia cognataria (Gn) (Lepidoptera: Geometridae). These herbivores cannot severely limit the density of purple loosestrife in southern Manitoba and any interactions with the introduced agents should be minimal. The predatory stink bug, Apoecilus bracteatus Fitch (Hemiptera: Pentatomidae), was identified as a potentially important predator of the introduced biological control agents, Galerucella pusilla Duftschmidt and Galerucella calmariensis (L.) (Coleoptera: Chrysomelidae).

Cassida azurea Fab. (Coleoptera: Chrysomelidae) was studied as an agent to control the weed bladder campion, Silene vulgaris (Moench) Garcke (Caryophyllaceae). To supplement previously published data on the beetle’s host range, additional no-choice experiments were conducted. First-stage larvae were offered seven plant species related to bladder campion. Only one adult male developed on Dianthus caryophyllus L. cv. China Doll and one female on Lychnis × haageana Lem. This female did not produce eggs when it continued to feed on L. × haageana. In tests with adults, oogenesis occurred only if fed with bladder campion, and one laid one egg while feeding on Gypsophila pacifica Kom. First-stage larvae did not develop to adults on three native North American Silene spp., but two adults developed on three other native species. Based on results from these experiments and reports in the literature, it was concluded that C. azurea has a very narrow host range and permission for field releases was granted in 1989. Releases were made in Manitoba, Saskatchewan, and Alberta from 1989 to 1993. Cassida azurea survived from 3 to 6 years and was considered established at 8 of the 18 release sites in the three provinces but has not yet increased to densities sufficient to reduce bladder campion populations.

Three new mymarid egg parasitoids of the carrot weevil, Listronotus oregonensis (LeConte) (Coleoptera: Curculionidae), are described: Anaphes cotei Huber from Nova Scotia; Anaphes listronoti Huber from Quebec; and Anaphes victus Huber from Quebec, Michigan, and Texas. A key to the species is given. Anaphes sorditatus (Girault), with which at least one of the new species was previously confused, is redescribed. Although listronoti and sorditatus cannot presently be distinguished morphologically, they are biologically distinct and have different hosts. Crosses between male sordidatus and female victus yielded female offspring in 27% of the tests but none in the reciprocal crosses. The corresponding control crosses resulted in 90 and 30% female offspring. Mating did not occur in attempts to cross sordidatus with listronoti. On three occasions an unidentified species of Anagrus was reared from field-collected carrot weevil eggs. This represents the first report of an Anagrus species from Curculionidae.

Yellow water pan traps and yellow sticky traps were used to collect Delia spp. flies in plots of canola, var. Tobin, for an entire growing season in the Peace River region of Alberta. At one or more times during the growing season, pan traps and sticky traps captured Delia radicum (L.), Delia floralis (Fallen), Delia planipalpis (Stein), or Delia platura (Meigen). Numbers of males and females caught varied dramatically between the two trap styles, both within and between the various species. Prior to the onset of flowering, cumulative captures of each of the four Delia spp. in pan traps were all significantly lower than on sticky traps for females and males. From the onset of flowering until trapping ended on 17 August, cumulative captures of D. radicum, D. floralis, and D. planipalpis females were similar in pan traps and sticky traps. Sticky traps, however, remained significantly better than pan traps for trapping all Delia spp. males, as well as D. platura females. Pan traps were more suitable than sticky traps for collecting intact specimens for positive identifications. Results indicate that a combination of sticky traps and pan traps should be used over an entire growing season when conducting initial surveys for Delia species in crops such as canola. In routine monitoring programs for Delia spp., sticky traps would be more efficacious early in the growing season and more practical than pan traps. The level of expertise required to accurately identify the Delia spp. complex in canola would be higher for sticky traps than for pan traps.