Honeydew utilization by the ant Lasius niger L. (Hymenoptera: Formicidae), honeydew excretion cost for the aphid Aphis craccivora Koch, and ant protection service for aphids against the lady beetle Coccinella septempunctata L. (Coleoptera: Coccinellidae) were examined in a laboratory. The duration of honeydew utilization by ants increased with increase in aphid density. The presence of ants shortened the residence time of the lady beetle larva on a plant and reduced the proportion of aphids eaten. At a density of 5 aphids per plant, one aphid with ants excreted honeydew at a frequency two times higher than that of an aphid without ants, but not at a density of 100 aphids per plant. Therefore, a larger aphid colony may increase the benefit and decrease the cost of ant attendance.

The sex pheromone of the spruce seed moth, Cydia strobilella (L.) (Lepidoptera: Tortricidae), has not yet been identified, but several chemicals were found to be attractive to males (reviewed by Grant et al. 1989). E8-Dodecenyl acetate (E8-12:OAc) at 0.3-3.0 μg doses was the only effective attractant for males in field experiments in British Columbia, Ontario, and Newfoundland (Grant et al. 1989). Our objectives were to (i) confirm that female C. strobilella produce E8-12:OAc as a pheromone component, (ii) determine whether females produce additional pheromone components, and (iii) investigate the die1 periodicity of pheromonal communication.

A field study was carried out to determine the intracrown distribution of the balsam fir sawfly, Neodiprion abietis Harris (Hymenoptera: Diprionidae), throughout the season on balsam fir, Abies balsamea L. (Pinaceae), during the first 2 years of an outbreak in western Newfoundland. Eggs were usually laid one per needle on current-year shoots, and the following year, newly emerged larvae usually initiated feeding on the same shoots. Balsam fir sawfly larvae were gregarious on needle and shoot levels in the early instars but gradually became solitary as larvae developed. The process of becoming solitary was not due to the increased physical area required for the growing larvae as some older individuals, in mainly solitary stages, were seen feeding together. Unlike the continuous change from gregarious to solitary at the needle and shoot levels, the seasonal variation in larval density among whorls varied in an inconsistent manner. The majority of early-instar larvae were found in the middle crown, but on at least one date in both years the majority of late instars were in the lower crown. Seventy-five percent of crawling larvae trapped within the crown were third and fourth instars, suggesting that changes in the intra-tree distribution are due to larval movement.

Wheat midge larvae, Sitodiplosis mosellana (Géhin), attack developing seeds and cause losses of common wheat, Triticum aestivum L., and durum wheat, Triticum durum Desf. (Olfert et al. 1985; Lamb et al. 1999). Insecticide applied as the crop flowers can reduce damage (Elliott 1988). The economic threshold varies from 4 to 7% of common wheat seeds infested by larvae, depending upon grade of wheat and cost of insecticidal control (Lamb et al. 2000). To make control decisions, farmers count adults at sunset during the period from heading to flowering (Elliott and Mann 1996), and apply insecticide if densities reach a nominal threshold of one adult per four or five wheat spikes (Anonymous 1993). Decisions must be made although no relationship has been detected between the number of adults in the crop and subsequent densities of damaging larvae (Oakley et al. 1998), and farmers have little confidence in their counts. The pest is difficult to sample because adults are small, short-lived, crepuscular, and are usually hidden in the crop canopy (Pivnick and Labbé 1993); eggs are microscopic (Mukerji et al. 1988); larvae feed inside florets (Lamb et al. 2000); and mature larvae and pupae are in the soil (Lamb et al. 1999). Sticky traps have been used to sample midges in sorghum (Merchant and Teetes 1992) and in wheat (Oakley et al. 1998), with mixed results. Our objective was to determine if catches of wheat midge adults on sticky traps can effectively guide farmers in making control decisions.

Plant bugs in the genus Lygus (Hahn) (Hemiptera: Miridae) are sporadic pests of canola, Brassica napus L. (Brassicaceae) and Brassica rapa L., in western Canada and infestations appear to have become increasingly common and severe in recent years. Surveys conducted from 1998 to 2000 identified a "northern" assemblage in the boreal ecoregion that was dominated by Lygus lineolaris (Palisot de Beauvois), with minor representation of Lygus borealis (Kelton), Lygus elisus (Van Duzee), and Lygus keltoni (Schwartz). A "southern" assemblage in the grassland ecoregions was dominated by L. keltoni, with a substantial abundance of L. elisus and L. borealis and with few L. lineolaris in the driest areas. The assemblage from the parkland ecoregion was variable but with few L. elisus. The boreal plains and parkland ecoregions of Alberta had the most serious and persistent infestations of Lygus spp. Relative species composition of the Lygus assemblage at the bolting stage was not related to the overall abundance of these bugs at the early pod stage. Lygus species assemblages were similar in terms of composition and relative abundance at the bolting and early pod stages of canola. A shift in species proportions in favour of L. lineolaris in the north and L. keltoni in the south and a decrease of L. elisus has taken place relative to studies conducted in the 1980's.

Mate acquisition in moths typically entails long range response of males to female-produced signals, although in several species males may attract females (Birch et al. 1990; Conner 1999; Phelan 1997). Tirathaba mundella Walker attacks oil palm in Southeast Asia (Barlow 1982; Kalshoven 1981). Larvae bore into and feed inside inflorescences and fruit bunches, causing a major reduction in oil production. Observations (Y Sasaerila, unpublished data) suggested that females are attracted to signaling males. Our objectives were to (i) determine the sex emitting or responding to sexual communication signals; (ii) describe calling and courtship behaviour; and (iii) determine the diel periodicity of sexual communication.

Assays were done in the laboratory and field to monitor the response of Pacific coast wireworm, Limonius canus LeConte, to food baits. A glass-plate assay was used in laboratory trials to study movement of wireworm larvae through soil in response to several food baits, including germinating seeds of grains, rolled oats [Avenu sauva L. (Poaceae)], carrot [Daucus carota L. (Umbelliferae)], and potato [Solanum tuberosum L. (Solanaceae)]. Studies were also done with these baits to determine effectiveness under field conditions. In both laboratory and field trials, germinating seed of wheat [Triticum aestivum L. (Poaceae)] and barley [Hordeum vulgare L. (Poaceae)] ranked higher in response by larvae than the remaining food baits. In the glass-plate assays, 65–70% of wireworms contacted the wheat or barley seed baits within a 2-h assay period. Corn [Zea mays L. (Poaceae)] seed and sliced carrot were also effective, with 60% of larvae contacting the baits. Rice [Oryza sativa L. (Poaceae)], rye [Secale cereale L. (Poaceae)], and potato were contacted by 30–45% of larvae. In the majority of assays, contact with the bait occurred within 30 min of the start of the assay. Trail lengths varied substantially among larvae (0–70 cm). The field studies showed that all food baits captured more wireworms than unbaited traps. A second assay conducted in the laboratory showed that moistened rolled oats were contacted with a higher probability if oats were aged 72 h following wetting (51% of larvae contacted the bait) than oats used immediately following wetting (28% of larvae). Field trials using baits composed of different volumes of rolled oats showed little evidence of a dose response in capture rates of L. canus, although all baits captured more wireworms than unbaited traps. These studies showed that L. canus is attracted to food baits in both laboratory and field trials, and that baits may prove useful to monitor populations of this pest in the field.

Males of Chymomyza mycopelates Grimaldi and Chymomyza exophthalma Grimaldi battled at sites where females fed and mated (but did not oviposit). Both sexes in the two species waved their brightly marked front legs during aggressive interactions, and males used these legs to strike and grasp opponents forcefully. During intense battles, male C. mycopelates also butted or pushed with their heads, whereas male C. exophthalma used their more strikingly wide heads to threaten with stereotyped displays, during which they also held their front legs folded against the sides of their eyes. Courtship behavior by male C. mycopelates involved tactile and perhaps visual displays with the tips of their front legs. Both species also fed by sweeping their front legs over the surface of fruiting fungi and by removing the spores from their legs with their mouthparts. Although male head width in C. exophthalma showed positive allometry, portions of the front legs that were used as signals and as weapons did not, and thus were not in accord with theoretical predictions that weapons and display devices would have steeper allometries.

In seed orchards of Douglas-fir, Pseudotsuga menziesii (Mirbel) Franco (Pinaceae), located in Washington State and Oregon, United States, we tested whether catches of male Douglas-fir cone gall midges, Contarinia oregonensis Foote, in pheromone-baited traps can be used to predict the extent of galled scales (= seed loss at harvest) caused by developing larvae. In 2000, 27 experimental blocks (4–7 ha each) were selected. In each block we recorded mean numbers of (i) male C. oregonensis captured in 20 pheromone-baited Wing traps, (ii) egg-infested scales in up to 50 conelets in early spring, and (iii) galled scales in up to 50 cones in late summer. In 2001, the experiment was repeated with 20 Delta traps in each of 26 experimental blocks. Moreover, catches of C. oregonensis and nontarget insects in Delta traps and Wing traps were compared in one additional orchard block in 2001. In both years there were positive correlations between mean numbers of egg-infested and galled scales and between mean numbers of captured male C. oregonensis and mean numbers of both egg-infested and galled scales, particularly when only experimental blocks with ≥50% of trees bearing at least 5 conelets were considered. Our results suggest that 4 or 2 captured male C. oregonensis in Wing or Delta traps, respectively, warrant insecticidal control of C. oregonensis. Delta traps, which captured fewer nontarget insects, would be more suitable than Wing traps for operational implementation of this technology.

Two species of bees native to China, Osmia excavata Alfken and Osmia jacoti Cockerell, were released in 1991–1993 to observe life-history characteristics and assess pollination efficiency. Osmia excavata successfully established in both coastal (Shandong Province) and interior (Hebei Province) habitats, whereas O. jacoti was only able to establish in the coastal habitat. Sex ratios (female:male) ranged from 1:1.05 for O. jacoti to 1:2.46 for O. excavata. Apple, Malus domestica Borkh (Rosaceae), pollination was enhanced following the release of either species in orchards in Shandong. Fruit diameter increased following the release of either Osmia species in 'Red Delicious' blocks compared with control blocks where no pollination treatment was applied. The number of seeds per fruit was also increased relative to controls, and the percentage of asymmetrical fruit decreased. Release of O. excavata produced the best results for this cultivar. For 'Ralls Janet', the number of seeds per fruit increased following the release of either species and the percentage of asymmetrical apples decreased. Effects on fruit diameter were confounded by poor cultural practices (i.e., lack of adequate fruit thinning) in these 'Ralls Janet' blocks. Fruit set increased relative to controls following release of either Osmia species for both apple cultivars. Release of O. excavata also produced higher fruit set relative to blocks that received hand pollination treatment; release of O. jacoti was better than hand pollination only for 'Red Delicious'. Observations on the behaviour of individuals showed that O. excavata averaged 49.6 foraging trips per day and set an estimated 3108 fruit on 'Ralls Janet'; O. jacoti made fewer foraging trips (average of 31.2) per day and set 1831 fruit. Both species were more efficient pollinators than Apis mellifera. Osmia excavata would appear to be a better candidate for commercial apple pollination than O. jacoti under conditions similar to those in this study.

We conducted laboratory experiments assessing the relationship between commercial greenhouse polyethylene coverings and bumble bee, Bombus impatiens Cresson (Hymenoptera: Apidae), activity and loss from ventilation systems. Bee activity was measured in four small greenhouses, each with a different polyethylene covering. Bee activity was quantified using photodiode tunnels mounted in the hive entrances. Contrary to commercial greenhouse experiments, there was no difference in bee activity based on covering type. There was a positive linear relationship between temperature in the experimental greenhouses and bee activity. The potential for bee loss through open ventilation systems for five covering types was quantified using a Y-maze decision box. Bees were more attracted to direct light than to light transmitted through ultraviolet (UV) blocking coverings, whereas bees were equally attracted to direct light as they were to UV-transmitting coverings. These experiments suggest that greenhouses with UV-transmitting plastics may result in less bee loss through ventilation systems.

The sounds produced by Metaleptea adspersa (Blanchard 1843) were recorded in captivity with an analogical tape recorder. The signal was digitized in the laboratory and studied with a software. Three types of sound were described: copulation, rivalry, and crepitation. All three sounds were produced only by males. The frequency of the sounds occupied a broadband, from 3–4 to 16 kHz, although the main peak frequency for each type of song differed. We also studied the structures involved in sound production. Copulation and rivalry songs were produced by the rubbing of the subcostal, radial, medial, and cubital 1 veins of the hind wing against the subcostal and radial veins of the tegmen; the enlarged cubital area of the hind wing acted as a resonator. Crepitation sound was produced by the cubital area of hind wing when its expanded membrane became taut.

Because Dioryctria amatella (Hulst) is a key pest in loblolly pine, Pinus taeda L. (Pinaceae), seed orchards in the southeastern United States, improved timing of insecticide applications would be valuable for its control. To time two fenvalerate (Pydrin® 2.4 EC) applications we tested four variations of a degree-day model that was developed to predicted when various proportions of D. amatella eggs would hatch during the spring generation. We compared reductions in Dioryctria spp. cone damage to unsprayed checks and a standard operational spray regime of four monthly applications of fenvalerate. In addition, we examined seeds from healthy cones to determine if sprays to control D. amatella also reduced seed damage caused by Leptoglossus corculus Say (Heteroptera: Coreidae) and Tetyra bipunctata (Herrich-Schäffer) (Heteroptera: Scutelleridae). Trials were conducted from 1984 to 1986 in two orchards in South Carolina and one in Alabama. Degree-day accumulations (threshold = 11 °C) were begun on the day when the cumulative number of male D. amatella equaled or exceeded five captured in 15 Pherocon 1C® traps baited with 100 μg of Z-11-hexadecenyl acetate. One application per year was insufficient to control D. amatella or reduced seed-bug damage. Two sprays based on D. amatella phenology significantly reduced coneworm and seed bug damage, and were as effective as four sprays applied monthly. None of the treatments reduce spring cone losses, which are primarily caused by Dioryctria merkeli Mutuura and Monroe. Several variations of the model performed well, but we suggest that the best, based on efficacy and ease of use, was when sprays were applied immediately after five males were caught (degree-day = 0) and again when the model predicted 50% of the spring generation eggs had hatched.

Bioassays and direct counts were used to assess the abundance of resting spores of the gypsy moth, Lymantria dispar (L.), fungal pathogen, Entomophaga maimaiga Humber, Shimazu and Soper in forest soils. Resting spores in soil collected in October, January, and March and held under refrigeration germinated as readily as spores collected in April, but those collected in April germinated faster. Bioassays of resting spores in soils from different sites in Connecticut were directly related to results obtained from physically counting spores in the soil, and weakly correlated with a previously developed forest-based bioassay. The number of resting spores in a site was inversely related to the number of years since the site had last been defoliated by the gypsy moth, resulting in an implied maximum viability of resting spores of about 10 years. This maximum longevity was similar to a direct measure of long-term resting-spore viability. The study implies that resting-spore load in the soil may be an important determinant of the ability of the pathogen to control the gypsy moth.

Egg load of newly emerged adult parasitoids of the southern pine beetle, Dendroctonus frontalis Zimmermann (Coleoptera: Scolytidae), was examined. Infested bark was collected from D. frontalis infestations in southwestern Arkansas (Clark and Montgomery counties; 1995), the Bankhead National Forest in Alabama (1999), and the Talladega National Forest in Alabama (1998–2000) between June and September of each collection year. Newly emerged parasitoid females were dissected and numbers of mature and immature eggs counted. There was no significant difference in number of eggs within a species and between parasitoids from the Bankhead National Forest compared with those from the Talladega National Forest in Alabama in 1999. There were differences in number of eggs within a species between years at the same location. Dendroctonus frontalis parasitoids in the family Pteromalidae (Hymenoptera) had the most mature eggs, followed by Braconidae (Hymenoptera) and Eurytomidae (Hymenoptera). Within the D. frontalis parasitoids in the family Pteromalidae, Dinotiscus dendroctoni (Ashmead) and Heydenia unica Cook and Davis had more mature eggs than did Roptrocerus xylophagorum Ratzeburg. Within the D. frontalis parasitoids in the family Braconidae, Meteorus hypophloei Cushman females contained the most mature eggs, followed by Dendrosoter sulcatus Muesebeck, Spathius pallidus Ashmead, and Coeloides pissodis (Ashmead). These data constitute a foundation for defining baseline egg load of the D. frontalis parasitoid complex.

Varroa destructor Anderson and Trueman females were placed in contact with queen, worker, and drone brood cells of Apis mellifera L. that were soon to be sealed. In a non-choice test, V. destructor adult females were introduced into a comb containing either queen or worker brood cells; 0.62 and 18.28% of the mites entered the queen and worker brood cells, respectively. Only 1 of the 11 mites that entered queen brood cells oviposited, laying a single egg. In another test, brood cells were combined in the same comb in a 1:25:3 queen:worker:drone ratio. The percentages of egg-laying mites in queen, worker, and drone brood cells were 16.66, 61.86, and 79.06%, respectively. When queen, worker, and drone brood cells were combined in equal proportions (33.3:33.3:33.3), percent infestation was significantly different among queen (3.25%), worker (49.12%), and drone (90.07%) brood. Multiple infestation was found in drone brood cells but not in others. Also, mites were inoculated into sealed queen cells. These cells contained either one or two mites (either at the egg or protonymph stage). Conversely, in a simultaneous test with worker brood cells, the offspring per foundress mite included a mean of three individuals (either at the egg, protonymph, or deutonymph stage). It is concluded that V. destructor can infest queen, worker, and drone brood cells, but drone brood cells are preferred; in addition, queen brood cells do not provide an optimal environment for reproduction because it causes a delay in mite oviposition and (or) progeny development.

Evidence for herbivory on early vascular plants in the Paleozoic has recently been accumulated from trace fossils and coprolites (Edwards et al. 1995; Labandeira 1998), although it is not well understood which arthropods were true herbivores during the Paleozoic. The great diversity of extant herbivorous insects was thought to have originated in the Cretaceous, when the adaptive radiation of angiosperms occurred; thus, it would be intriguing to find ancient plant–herbivore interactions on extant primeval vascular plants. In this paper, I report a unique dipteran fly associated with a species of the class Lycopsida as the first record of non-lepidopteran herbivory on the extant plant order Lycopodiales.

Seasonal activity of carrot weevil, Listronotus oregonensis (LeConte), adults, eggs, larvae, and root feeding was studied in plots of parsley, Petroselinum crispum (Mill.) Nyman ex A.W. Hill, by sampling weekly from mid-May to the first week of September in 1998 and 1999. The initial population of overwintering adults, one complete generation, and at least a partial second generation were observed. The majority of eggs were deposited in June and most of the larvae were counted in July; the greatest damage was noticed from July onward. In both 1998 and 1999, the overall seasonal means of adults, eggs, larvae, and root feeding were significantly different among plots that were planted on different dates. Root feeding and all carrot weevil life stages sampled steadily decreased from the earliest to the latest planting. Most of the damage occurred in parsley plantings sown from late February until the third week of April. The number of eggs removed from parsley plants during the first cutting was significantly different among planting dates, but the impact of this removal may not be significant in infestation reduction. Results of this study will help parsley growers to target when control measures for carrot weevil will be most effective and which plantings are most likely to be damaged.

The carrot rust fly, Psila rosae F., is a major pest of carrots, Daucus carota L. (Apiaceae), in the principal production areas of Newfoundland, Quebec, Ontario, and British Columbia (Boivin 1994), as well as in temperate Europe and New Zealand (Ellis and Hardman 1992). Larvae cause damage by tunneling into the roots (Boivin 1994), reducing both yield and marketability. The insect was first recorded in Canada in 1885 but was not reported in Newfoundland until the 1930s (McClanahan and Niemczyk 1963). By the 1950s, P. rosae had spread from an initial infestation around St. John's to commercial farms and home gardens throughout the carrot-growing areas of Bonavista and Conception bays in eastern Newfoundland (Boivin 1994).