Many species respond to risks and benefits of dispersal that vary over the short term through condition-dependent dispersal. We used wind tunnels to investigate how abiotic factors, spiderling age, and indicators of environmental quality affect aerial dispersal behaviour of spiderlings in Dolomedes triton (Walckenaer) (Araneae: Pisauridae), a denizen of temporary habitats. More than half of all spiderlings exhibited preballooning, ballooning, or spanning behaviours. Warm temperatures (>22.5 °C) and low wind speeds (<2.0 m/second) increased aerial dispersal. Aerial dispersal behaviour increased significantly until 5 days after hatch, after which it decreased, coinciding with the onset of active hunting by spiderlings. In contrast, cues about ambient food availability (egg sac number and food limitation of the mother) and potential resource competition or risk of cannibalism (conspecific density) did not affect aerial dispersal propensity. Offspring from different females ballooned in different proportions, except at the peak of dispersal, but a female's reproductive output and propensity of her offspring to balloon were uncorrelated. Thus, it appears that spiderlings of D. triton adopt a fixed strategy of high dispersal rate under optimal abiotic conditions, rather than reducing dispersal in response to cues about local food availability or conspecific density.

Aphid species colonising ferns belong to the subfamily Aphidinae (Hemiptera: Aphididae) and the majority of these to the tribe Macrosiphini. A new genus in this tribe and its type species: Gibbomyzus pteridophytorumnew genus, new species, are established. Apterous and alate viviparous females are described from specimens collected on Blechnum buchtienii Rosenstock (Blechnaceae) in Costa Rica and on Pteridium aquilinum (Linnaeus) Kuhn (Dennstaedtiaceae) and an unidentified fern in Mexico. The taxonomic validity of the two new taxa is discussed based on morphological and molecular data. Morphologically, the new genus is compared with genera with swollen siphunculi recorded in the New World, and also with genera living on ferns anywhere in the world. The identification key by Blackman and Eastop to aphids living on ferns is modified. Molecular analyses were carried out on the sequences of a fragment of the mitochondrial gene encoding for cytochrome c oxidase subunit 1 and of a fragment of the nuclear gene encoding elongation factor-1 alpha. In both analyses, G. pteridophytorumnewspecies sequences showed considerable divergence (∼4% or more) from those of 23 other species from diverse genera of Macrosiphini, supporting the conclusions of the morphological study and justifying the establishment of the new genus.

The vector competence (VC) of Aedes aegypti (Linnaeus) (Diptera: Culicidae) varies geographically and is affected by both genetic and environmental factors. Understanding the molecular mechanisms that influence VC may help develop novel control strategies. The selection of susceptible and refractory strains is the first step in this process. We collected immature A. aegypti in the field and established strains that were susceptible and refractory to Dengue-2 virus by isofamily selection through several generations. Infection was detected by immunofluorescence of head or midgut tissues to determine infection barriers and the % of VC by tissue. We selected three strains: Susceptible (Cali-S) (96.4% susceptible at F19), Refractory with a midgut escape barrier (Cali-MEB) (44.1% refractory at F15), and Refractory with a midgut infection barrier (Cali-MIB) (40% refractory at F16). The effects of the infection were measured using Kaplan–Meier survival rates over the first seven generations. All selected strains showed a similar decrease in survival and in the number of eggs laid/female through the seven generations, suggesting that changes were a result of the selection process rather than the virus infection. The results of this study suggest that VC is associated with multiple genes, which have additive effects on susceptibility.

Sex attraction studies were carried out to investigate the mate-finding behaviour of invasive Vespula vulgaris (Linnaeus) (Hymenoptera: Vespidae) wasps. Delta traps were baited with live, caged males, and gynes (virgin queens) of V. vulgaris to determine whether either sex produced a long-range sex attractant. Traps baited with gynes caught 71 males, while the controls and live-male wasp baited traps did not catch gynes. Wind tunnel trials were performed to verify if the signal produced by the gynes was chemical in nature. First, V. vulgaris males were flown to live caged gynes, where more than half of the males tested flew upwind in a zigzagging pattern and made contact with caged gynes. Males were also flown to hexane rinses of gynes and flew upwind in a zigzagging pattern towards the gyne extract, although none made contact with the cotton roll stimulus. The results presented here demonstrate conclusively that V. vulgaris gynes produce a sex pheromone.

Surveys of dung beetles establish the dominance of exotic taxa associated with cattle dung on native grasslands in southern Alberta, Canada. Of the 12 species recovered, eight were of European origin and comprised 92.2% of the total catch of 187 963 beetles. Most common were Chilothorax distinctus (Müller), Onthophagus nuchicornis (Linnaeus), and Colobopterus erraticus (Linnaeus) (Coleoptera: Scarabaeidae). The abundance of C. distinctus has been known in the region since the 1920s, whereas that of O. nuchicornis only was first reported in the 1990s. The abundance of C. erraticus has not previously been observed in the region and identifies the species as the newest addition to the endemic fauna. The diversity of native species on pastures in southern Canada and adjacent states is depauperate, such that the establishment of European taxa has appreciably increased levels of bioturbation in pasture ecosystems. The success of these exotic species on northern pastures may reflect a level of cold-tolerance greater than that of most native species.

Cette étude a été menée dans un verger d'olivier Olea europaea (Linnaeus) (Oleaceae), dans la région semi-aride d'Ain Touta (Batna, Nord-est Algérie) au cours de la période allant de janvier 2009 à décembre 2010. Le suivi démo-écologique régulier de la cochenille violette de l'olivier Parlatoria oleae (Colvée) (Hemiptera : Diaspididae) a montré que l'espèce évolue en deux générations annuelles : une génération printanière et l'autre automnale. Contrairement à d'autres régions du monde, la ponte est plus tardive avec une durée plus étalée à Ain Touta. Les pontes moyennes variaient de 10,05 ± 1,96 à 10,47 ± 1,15 œufs/femelle pour la première génération et de 9,9 ± 1,69 à 9,16 ± 2,05 pour la deuxième génération. Ces valeurs sont faibles comparées aux moyennes notées dans d'autres régions. L'analyse statistique a montré une variation significative des effectifs de tous les stades entre les mois, mais seulement des effectifs des L2 et des femelles adultes entre les années. Ceci serait en relation avec le phénomène d'hivernation noté pour les stades L2 et les femelles adultes avec des périodes d’étalement différentes d'une année à une autre. Entre les générations, la variation des effectifs était significative chez les pro-nymphes et nymphes ainsi que chez les mâles adultes.

The western spruce budworm, Choristoneura occidentalis Freeman (Lepidoptera: Tortricidae), is an important pest of western North American coniferous forests, where its principal larval host is Rocky Mountain Douglas-fir, Pseudotsuga menziesii subspecies glauca (Beissner) Murray (Pinaceae). In southwestern Alberta, Canada, populations were recently discovered feeding on an unconventional host, an Engelmann spruce, Picea engelmannii Parry ex. Engelmann × white spruce, Picea glauca (Moench) Voss hybrid (Pinaceae), in a transition zone between the two major forest types characterised by these conifer species. We use molecular evidence to verify the species identity of outbreaking Choristoneura populations collected from Douglas-fir and hybrid spruces in southwestern Alberta in 2009, and characterise the larval and male moth phenology. Both mitochondrial and microsatellite markers confirmed these populations as C. occidentalis, but admixture with Choristoneura fumiferana (Clemens) (Lepidoptera: Tortricidae) was detected in some individuals. Few differences associated with separate host trees were evident in the phenology of larvae and the flight period of male moths.

Traits such as larval growth rate and head capsule width are often measured in economically important insects to determine their developmental stage. However, these traits have the potential to vary between genotypes or in response to several ecological factors. To determine whether geographic or ecological factors cause variability in the head capsule width of Altica sylvia Malloch (Coleoptera: Chrysomelidae), and to verify whether measures of head capsule width are adequate to identify larval instars in this species, A. sylvia larvae were recovered from 35 fields of Vaccinium angustifolium Aiton (lowbush blueberry; Ericaceae) of eastern New Brunswick, Canada. The distribution of head capsule widths varied in response to accumulated degree-days, A. sylvia larval density, and latitude. An overlap between measures of head capsule width of first-instar and second-instar larvae in fields supporting a high density of A. sylvia larvae suggested that intraspecific competition caused a reduction in larval growth rate that affected head capsule development and may have induced developmental polymorphism. Based on these results, we stress that the sampling protocol of studies conducted to determine head capsule width intervals in a species should include diverse ecological settings as well as several locations within the range of the species.

Seasonal patterns of abundance and population variability were determined for Macrosiphum euphorbiae (Thomas), Myzus persicae (Sulzer), and Aphis nasturtii (Kaltenbach) (Hemiptera: Aphididae) in potato plots from weekly samples for 28 years. All species showed a single annual peak, but arrived and reached peak abundance at different times. Population variability (PV, a proportion between 0 and 1) for the week of peak abundance was close to that of other sample weeks and mean seasonal abundance. Based on mid-season abundance, PV of 0.76 for M. persicae differed significantly from 0.80 for A. nasturtii, as well as from 0.59 for M. euphorbiae. A weekly time scale for abundance, initiated at an early stage of plant growth, produced slightly different estimates of PV early and late in the season than a scale centred on peak abundance for each species. PV at the time of invasion differed from estimates for the rest of the summer. The annual abundance used to estimate PV was best determined in the context of aphid life history. Nevertheless, PV provided a robust and precise metric for comparing population variability among the three species, regardless of their seasonal patterns of abundance.

Seasonal patterns in the taxonomic and functional structure of epigeic Coleoptera assemblages in wet and mesic habitats were studied in Kugluktuk, Nunavut, Canada. Using pan and pitfall traps, 2638 beetles were collected between 21 June and 13 August 2010. Fifty species (including 17 new territory records) in 11 families were identified. The biomass of each specimen was estimated, and each was assigned to a functional group. Species composition differed between habitats throughout the active season and there was a rapid compositional turnover even though species diversity was similar in both habitats and among sampling periods. The functional beetle assemblages in the two habitats were different, and both assemblages experienced seasonal turnover in function; this effect was more pronounced in the mesic habitats. The beetle fauna in both habitats was predominantly entomophagous. We also examined the influence of seasonal weather patterns on assemblage structure: there is a significant relationship between mean daily temperature and assemblage structure. This relationship indicates that changes in weather (or longer-term changes in climate) could affect the diversity and ecological function of insects in this system. Given the significance of insects in the north, this could result in important changes to northern ecology.

The present study was designed to investigate the influence of mate choice in terms of age on reproductive performance and offspring attributes of parthenium beetle, Zygogramma bicolorata Pallister (Coleoptera: Chrysomelidae). Age-based mate choice was most evident in the middle-aged adults. Results revealed that middle-aged males and females were significantly preferred as mates by their middle-aged counterparts. Younger and older females did not show any preference for males of any age group. On the other hand, younger males showed a bias against old females, while older ones did not show any age-based preference for mates. Both fecundity and percent egg viability were significantly influenced by female and male age, respectively. Fecundity was highest in middle-aged females followed by young- and old-aged ones, with similar trend observed in relation to male age effects on egg viability. The development and survival of immature stages borne out of mate choice decisions of adults was influenced by mother's age. Offspring of middle-aged females developed fastest and survived longer than those of younger and older ones.

Frontalin, seudenol, and a spruce terpene blend are key components of a lure for monitoring spruce beetle, Dendroctonus rufipennis (Kirby) (Coleoptera: Curculionidae: Scolytinae) in eastern Canada, catching the highest number of beetles in several field trials. The standard two-component commercial lure for this species, developed from populations in western North America and composed of 95%:5% (±)-α-pinene and frontalin, failed to elicit attraction to traps in Atlantic Canada; thus a series of trapping experiments were conducted to identify an improved combination of pheromone and host volatiles for this region. Analysis of volatiles from D. rufipennis collected from Newfoundland and Nova Scotia, Canada detected seudenol as an additional female-produced component. Laboratory analysis of the eastern host (Picea glauca (Moench) Voss; Pinaceae) detected the presence of 75%:25% (±)-α-pinene; however, a two-component lure comprised of 75%:25% (±)-α-pinene and frontalin caught no more beetles than an unbaited control. Frontalin and seudenol alone or spruce terpene blend and ethanol alone typically had among the lowest trap catches, but when combined they caught the highest numbers of D. rufipennis, supporting the hypothesis that host volatiles synergise attraction to pheromones. Our results highlight the importance of geographic variation in the response to pheromones and kairomones in this bark beetle.

Outbreaks of geometrid defoliators in subarctic birch forest in Fennoscandia often occur at high altitude in a distinct zone along the tree line. At the same time, moth larvae may not have an impact on the forest at lower altitude. Directly adjacent outbreak and nonoutbreak areas offer unique opportunities for studying the underlying mechanisms of outbreaks. Within two altitudinal gradients in coastal northern Norway, we investigated whether altitudinal outbreaks might be caused by release from pupal predation by ground-dwelling invertebrates such as harvestmen (Opiliones), spiders (Araneae), rove beetles (Coleoptera: Staphylinidae), carabid beetles (Coleoptera: Carabidae), and other beetles (Coleoptera). We predicted a consistently higher abundance of such generalist predators at low versus high altitudes. Our results did not support this prediction. There was no consistent altitudinal variation in the abundance of predators that could be related to zonal moth outbreaks in the birch forest slopes. In addition, none of the predator groups investigated showed any numerical response to a distinct outbreak of winter moth that took place during the course of the study. Consequently, localised moth outbreaks at the altitudinal tree line in northern Norway cannot be explained by the release from pupal predation by the predator groups examined here.

The apple clearwing moth, Synanthedon myopaeformis (Borkhausen) (Lepidoptera: Sesiidae), is a day-flying species that feeds on floral nectar of many plants. In British Columbia, Canada, this invasive moth is often observed feeding on visually conspicuous showy milkweed, Asclepias speciosa Torrey (Apocynaceae). We measured the spectral efficiency of the compound eyes of S. myopaeformis in the context of their capacity to discriminate the measured spectral reflectance from inflorescences of A. speciosa, and conducted histological examination of these eyes to determine whether they possess apposition type ommatidia, as commonly observed in diurnal butterflies. Light micrographs of the compound eyes in S. myopaeformis revealed eucone apposition type ommatidia, which is consistent with the diurnal behaviour of the moth. Electroretinograms on compound eyes revealed they were particularly efficient at absorbing ultraviolet (UV) wavelengths in the 335–370 nm range and green wavelengths in the 495–560 nm range. These results support the conclusion that the compound eyes of S. myopaeformis have the capacity for dichromatic vision based on UV and green photoreceptors. However, spectral reflectance curves obtained from inflorescences and foliage of A. speciosa revealed no evidence of UV reflectance, making it less likely that colour plays a primary role in the attraction of S. myopaeformis to A. speciosa.

Cucullia umbratica Linnaeus (Lepidoptera: Noctuidae), Agnippe prunifoliella Chambers (Lepidoptera: Gelechiidae), and Bryotropha plantariella Tengstrom (Lepidoptera: Gelechiidae), were significant bycatch in pheromone-based trapping systems for red-striped fireworm, Aroga trialbamaculella Chambers (Lepidoptera: Gelechiidae), in Nova Scotia, Canada. Cucullia umbratica is a European introduced species and a new macrolepidopteran recorded in continental Canada. The only previous record of this moth in North America was from the Magdalen Islands (Québec, Canada). Potential attractants for B. plantariella, A. prunifoliella, and C. umbratica are a result of this bycatch investigation.

To investigate how bee (Hymenoptera: Apoidea) communities repopulate habitat following severe disturbances, we compared assemblages in new, regenerating landfill sites planted in 2003, recent landfill sites planted in 2000, and control meadows relatively undisturbed for >40 years. All sites were identically sampled using pan traps and sweep netting, from early May to late September 2003, equalising collection effort among sites. In addition, we carried out five-minute aerial net samplings wherever sites contained large patches of wildflowers. We predicted that abundance and diversity of bees would be highest in recent sites and lowest in new sites. This prediction was partially supported: bees were most abundant in recent sites followed by control, then new sites, but species richness was highest (82 species) in recent sites, followed by new sites (67 species), then control (66 species). A randomisation analysis showed that there were more species than expected in new sites and fewer than expected in control sites. Differences in blossom availability likely explain differences in bee abundance and diversity among habitat regeneration levels. Overall, our results suggest that the bee community recolonised newly available sites immediately in the first year and that bee diversity and abundance increased for at least three years, subsequently declining between three and 40 years.

Adult parasitoid females can obtain proteins and lipid by consuming the haemolymph of their host. In Trichogramma Westwood (Hymenoptera: Trichogrammatidae) species, host feeding on the host egg occurs after oviposition and leads to smaller offspring. We tested the effect of age and hunger on host-feeding behaviour of female Trichogramma euproctidis Girault. Young and old females, either starved, water fed, or honey fed, were observed and the host-feeding frequency, duration, distribution, and number of hosts used for nutrition were measured. The sex ratio (proportion of males) allocated to parasitised hosts where host feeding occurred and time taken to parasitise 10 hosts (indicator of female mobility) were also noted. The majority of females host fed on the first host encountered. Age had no impact on frequency, duration, number of hosts used, and mobility of T. euproctidis. Starved females host fed longer and were less mobile. The sex ratio of the progeny emerging from the first host parasitised was more male biased when host feeding occurred. Host feeding had no effect on the sex ratio deposited elsewhere in the sequence of hosts encountered. Age of female had no effect on host feeding, possibly because host feeding incurs little cost for this species. To host feed on the first host parasitised, in which a male is allocated, is less costly in terms of fitness and represents a strategic choice for the female.

Artificial diet is commonly used to rear the spruce budworm, Choristoneura fumiferana (Clemens) (Lepidoptera: Tortricidae), in the laboratory. While its effect on spruce budworm performance is relatively well studied, no information exists about the influence of rearing diet on larval parasitism. In this study, spruce budworm larvae reared in the laboratory on artificial diet or balsam fir, Abies balsamea (Linnaeus) Miller (Pinaceae), foliage were introduced in the field to compare parasitism. Additionally, a laboratory choice test was conducted with the larval parasitoid Tranosema rostrale (Brischke) (Hymenoptera: Ichneumonidae). No significant influence of spruce budworm rearing diet on parasitism in the field was found. However, in the laboratory, T. rostrale attacked significantly more foliage-fed larvae. We conclude that even if initial differences in parasitism may exist between diet-fed and foliage-fed larvae in the laboratory, spruce budworm larvae reared on artificial diet can be used in field studies investigating parasitism of wild spruce budworm populations without concern that the food source would affect parasitism.

Despite increasing worldwide interest in host–parasitoid food webs, the parasitoid communities of the high Arctic remain poorly explored. To allow analyses of global patterns, and to detect the effects of ongoing climate change, such data are urgently needed. In this paper, we describe a systematic effort to characterise the high-Arctic Hymenoptera and Diptera parasitoid community associated with Lepidoptera hosts of the Zackenberg Valley (74°30′N, 21°00′W), northeast Greenland. Here, we first sampled adult parasitoids by a combination of Malaise traps, pitfall traps, and, less extensively, yellow pan traps and sweep netting. We then identified the host use of individual parasitoid taxa by rearing a large number of host individuals and species across multiple years. We now describe our preliminary findings on the species diversity of the target community, on trophic links between hosts and parasitoids, and on the sampling effort and techniques needed to characterise the community. We report on 30 local parasitoid taxa representing four families, three of which are species new to Greenland. In describing the community, we make a specific effort to summarise what is known about the taxonomy, phenology, and host use of the component species, to the benefit of future research in the area.

House sparrows (Passer domesticus (Linnaeus), Aves: Passeridae) were introduced into eastern North America in the mid 1800s and have been expanding their range since then. We collected sparrows from two sites in Alberta, Canada (Edmonton: 58 birds; Onefour: 13 birds), and compared symbiont richness and prevalence between them and between Alberta and two states in the United States of America. We found 17 species of symbionts: 13 mites, three insects, and one trematode. Richness of symbionts in Alberta was very similar to that in the United States of America sites. The most striking difference was absence of the feather mite Proctophyllodes troncatus Robin (Acari: Proctophyllodidae) on sampled hosts in Alberta.