In 2010–2011, we studied the European oak borer (EOB), Agrilus sulcicollis Lacordaire (Coleoptera: Buprestidae), in Michigan, United States of America, and made comparisons with the native twolined chestnut borer (TLCB), Agrilus bilineatus (Weber). EOB adult flight began and peaked before TLCB. More EOB females were captured on purple and white compared with yellow and green sticky traps. More TLCB females were captured on purple, followed by yellow, green, and white, respectively. Male EOB and TLCB did not show a significant colour preference. EOB completed development primarily from areas of artificially girdled trees where the phloem had died soon after trees were girdled, while TLCB usually developed in areas of girdled trees that had some live phloem present. Both EOB and TLCB successfully attacked and emerged from girdled Quercus alba Linnaeus, Quercus robur Linnaeus, and Quercus rubra Linnaeus (Fagaceae) trees. No live EOB or TLCB were found in two ungirdled and apparently healthy Q. robur trees that were dissected. EOB attacked and emerged from Q. alba, Q. robur, Q. rubra, and Quercus velutina Lamarck trap logs. Differences in the pronotal groove and terminal processes can be used to distinguish EOB from TLCB larvae. Five species of parasitoids were reared from EOB and four from TLCB.

The Microgastrinae wasp Diolcogaster claritibia (Papp, 1959) (Hymenoptera: Braconidae), a parasitoid of the diamondback moth, Plutella xylostella (Linnaeus, 1758) (Lepidoptera: Plutellidae), is recorded from the Nearctic region (Alberta, Manitoba, and Ontario, Canada) for the first time. In spite of some minor morphological and molecular (DNA barcoding) differences, the available data indicate that the European and New World specimens should be considered one species, but more specimens and loci need to be sampled to conclusively determine the phylogeographic history of the species. Diolcogaster claritibia seems to be widely distributed within the Holarctic, and the molecular data suggest that it was recently introduced to North America from Europe.

Nutritional variability in resources may cause differential mortality between sexes resulting in biased sex ratios. If males and females differ in fitness, then mortality of the more sensitive sex can cause a bias in sex ratios, and can stimulate dispersion of males. We reared three generations of spruce budworm (Choristoneura fumiferana (Clemens); Lepidoptera: Tortricidae) on two artificial diets: a “normal” diet that provided all nutritional requirements for development and a “stress” diet (deficient in sugars and slightly higher in nitrogen), that simulated deterioration of food quality during outbreak conditions and had a detrimental impact on larval survival, development and growth. We tested the effects of continued nutritional stress on the sex ratio of pupae and adults. We found biased sex ratios in favour of males related to diet. Low quality food resulted in fewer females. This distortion was observed from the second generation onward, with a lower percentage of females reaching the pupal and adult stage. These results provide evidence that nutritional variation causes differential mortality between sexes, suggesting that females are more sensitive to nutritional stress. This is the first study that demonstrates sex ratio distortion due to nutritional selection pressure in spruce budworm. Our results indicate the importance of studying sex ratio distortion of spruce budworm in outbreak conditions.

L'influence de différents régimes trophiques sur la capacité de survie et la longévité d'une espèce zoophytophage (Macrolophus pygmaeus Rambur ; Hemiptera : Miridae) a été étudiée. Les différentes sources trophiques, présentées seules ou en combinaison étaient de l'eau libre, une plante (tabac), et une proie (œufs d’Ephestia kuehniella Zeller ; Lepidoptera : Pyralidae). Le régime trophique a fortement influencé la longévité et la survie des adultes quel que soit leur sexe. L'eau, libre ou apportée par la plante, est une ressource indispensable à la survie. La plante, comparée à l'eau libre, n'a pas eu d'effet significatif sur la longévité mais a influencé positivement la survie. On a observé un effet certain de la présence simultanée de l'eau et des œufs.

Multiple interactions occurring within aphidophagous guilds determine their final predation outcomes, i.e., antagonistic, additive, or synergistic. Based on these predatory outcomes, the suitability of guilds in suppressing aphid pests is determined. The present study assesses the efficacy of 11 guilds, formed from both larval and adult stages of four locally abundant aphidophagous coccinellids (Coleoptera: Coccinellidae), while exploiting the pea aphid, Acyrthosiphon pisum Harris (Hemiptera: Aphididae). The observed antagonistic effects within these guilds are resultants of enhanced predator–predator interactions due to the size and diversity of guild predators. Smaller ladybird predators maintained their usual body mass, probably by increasing their conversion efficiencies to compensate for their reduced prey consumption. However, larger ladybirds reported loss in their body mass, owing to their higher energy needs. The overall guild conversion efficiencies and growth rates were reduced. Among the experimental guilds, the observed prey mortalities were relatively higher in two-predator guilds, and within these two-predator combinations, the higher prey mortalities were recorded in those guilds where Coccinella septempunctata was one of the predators.

To characterise their functional diversity and seasonal activity, dung beetles (Coleoptera: Scarabaeoidea) were collected with baited pitfall traps at three sites for three years on a native grassland in southern Alberta, Canada. The total collection of 125 820 beetles comprised 12 species of which eight were of European origin. For each combination of site and year, assemblages were dominated by two or three core species of European origin that represented 70–95% of total beetles and more than 75% of total biomass, but only 10–30% of species richness. Core species consistently included Onthophagus nuchicornis (Linnaeus) and occasionally Chilothorax distinctus (Müller) and Colobopterus erraticus (Linnaeus). Coexistence of these core species appears to be facilitated by differences in their size, seasonal activity, and life history traits.

Surveys were conducted in Ontario and Québec, Canada to determine the parasitoid communities associated with Ceutorhynchus Germar (Coleoptera: Curculionidae) weevil species that are potential nontarget hosts of candidate biological control agents of the cabbage seedpod weevil, Ceutorhynchus obstrictus (Marsham). New host plant associations are documented for Ceutorhynchus americanus Buchanan, Ceutorhynchus neglectus Blatchley, and Ceutorhynchus omissus Fall. More than 18 species of Chalcidoidea (Hymenoptera) were associated with six Ceutorhynchus species reared from siliques and stems of Brassicaceae plants. Silique-feeding Ceutorhynchus species supported a more diverse parasitoid community than stem-feeding or root crown-feeding species. The major components of the parasitoid assemblage of the native C. neglectus included Mesopolobus gemellus Baur and Muller, Mesopolobus moryoides Gibson, Trichomalus lucidus (Walker) (Hymenoptera: Pteromalidae) and a cryptic species complex previously reported as Necremnus tidius (Walker) (Hymenoptera: Eulophidae). These species, plus Trimeromicrus maculatus Gahan (Hymenoptera: Pteromalidae) were the main parasitoids attacking the native C. omissus. The major parasitoids associated with the accidently introduced Ceutorhynchus erysimi (Fabricius) and Ceutorhynchus typhae (Herbst) included T. maculatus, the N. tidius species complex, M. gemellus, and M. moryoides. Trichomalus perfectus (Walker) (Hymenoptera: Pteromalidae), a major parasitoid of C. obstrictus in Europe, is an accidental introduction first reared in Canada from that host in 2009 and first collected from C. omissus in 2011. Mesopolobus gemellus is shown to have a broad host range. These findings highlight the need for a cautious approach before introducing new biological control agents.

The European Fire Ant, Myrmica rubra (Linnaeus) (Hymenoptera: Formicidae), is an invasive stinging ant that has only recently been recorded in Newfoundland, Canada. The goal of the present study was to investigate the origins of M. rubra ants in Newfoundland. We analysed mtDNA sequences from the cytochrome b and cytochrome c oxidase I genes of ants from six localities in Newfoundland, and neighbouring regions of eastern Canada and the United States of America, and compared them with mtDNA data from a recent wide-scale phylogeographical study of the ant throughout Europe. There is evidence for at least four distinct sources of ants on the island. The putative routes of colonisation of the ant to Newfoundland are discussed, as are the possible reasons why it went undiscovered for many decades.

Sperm competition generates selection for male traits to prevent it. These traits remain unclear in species where males compete for a virgin who is briefly receptive. Males of the parasitoid wasp Ooencyrtus kuvanae Howard (Hymenoptera: Encyrtidae) compete over females following emergence from host egg masses. Males engage virgins in a precopulatory ritual, mate, and then immediately perform a postcopulatory ritual after which the female becomes unreceptive. Often, sneaker (M2) males copulate with a female while she is engaged in the postcopulatory ritual, and they also perform the postcopulatory ritual. We investigated (i) paternity of M1 and M2 males using DNA microsatellite analysis, (ii) copulation and postcopulatory behaviour of both males, and (iii) morphological adaptations of the aedeagus for sperm removal. Eighty-eight percent of M1 males sired all daughters when they were first to perform the precopulatory and postcopulatory ritual, suggesting a linked effect of both rituals on paternity. The number and length of copulations by both males did not affect paternity, and the shape of the aedeagus does not seem to facilitate sperm removal. Our results are consistent with the hypothesis that postcopulatory rituals represent forms of mate guarding that function to increase paternity in the context of sperm competition.

The taxonomy and identification of mayflies of the Baetis vernus group (Ephemeroptera: Baetidae) represents a major challenge in both Europe and North America. The recent description of B. jaervii Savolainen from Finland, a species taxonomically close to the Palaearctic taxon Baetis macani Kimmins and the Nearctic B. bundyae Lehmkuhl, called for clarification of the status and distribution of these species in northernmost Europe. We generated mtDNA COI sequences for establishing the identity of the collected samples. Based on these data we conclude that B. bundyae does occur in northeastern Finland in sympatry with B. macani. Accordingly, this taxon shows a highly interesting distributional pattern across the Nearctic and western Palaearctic regions.

An individual-based phenology model for western spruce budworm, Choristoneura occidentalis Freeman (Lepidoptera: Tortricidae), was developed using stage-specific rates of development, oviposition, and egg hatch observed under controlled conditions at several temperatures. Model output was compared with age distributions estimated by sampling field populations of budworm at several locations in British Columbia, Canada, over many years. The fit of the model was very good for the entire life cycle of the insect. We further validate the model by comparing output with independent observations of moth flight phenology of C. occidentalis and Choristoneura fumiferana (Clemens) in populations of Cypress Hills, Canada and illustrate spatial variation in the seasonal occurrence of early-stage feeding western spruce budworm over most of its range in western Canada. In addition to serving as the underlying structure for the modelling of population dynamics at the seasonal level, the model can be used to predict the time of occurrence of different life stages for precise timing of pest management operations.

The Nearctic leafhopper Scaphoideus titanus Ball (Hemiptera: Cicadellidae) was accidentally introduced in Europe, where it became the vector of the ‘Candidatus Phytoplasma vitis’ phytoplasma causing the ‘Flavescence dorée’ disease of grapevine plants. A time-varying distributed delay model, simulating the successive occurrences of egg hatching, nymph presence, and adult emergence, is extended here to represent multi-generation infestation patterns of grapevine plants inhabited by eggs, nymphs, and adults. The model extension includes intrinsic mortality, mortality caused by plant dormancy, and low temperatures, development of diapausing and post-diapausing eggs, fecundity rates, and adult longevity. Field observations and published data were used to estimate parameters. The model was validated with five years canopy infestation data from five vineyards not subjected to insecticide treatments and found to have satisfactory explicative and predictive qualities. The model output is most sensitive to a 10% variation in the upper threshold and in the shape parameters of the survivorship function and least sensitive to a 10% variation in the shape parameters of the development function and the survivorship level. Recommendations are made to take into account other factors than temperature and plant phenology and include a wider geographical area in further model development.

We report for the first time the occurrence of the well-known Eurasian and north African parasitoid Cotesia vanessae (Reinhard) (Hymenoptera: Braconidae) in North America. Specimens were reared from Chrysodeixis chalcites (Esper) and Trichoplusia ni (Hübner) (Lepidoptera: Noctuidae) recovered from several locations in southwestern Ontario, Canada, and detected by DNA sequencing from one Autographa californica (Speyer) (Lepidoptera: Noctuidae) in southern Alberta, Canada.

Larvae of gall making tipworm feed on and injure the apical meristems of cranberry shoots/uprights, disrupting vegetative growth. The majority of tipworm-injured flowering uprights do not resume vegetative growth via activation of lateral axillary buds (side-shoots) before the onset of dormancy. Furthermore, growth and flowering of uprights that fail to produce side-shoots after injury may be inhibited in the following year. In cranberry, limited availability of total nonstructural carbohydrates during fruit development has been reported. Thus, competition between developing fruit and lateral axillary buds for available resources may suppress vegetative regrowth in tipworm-injured flowering uprights. We carried out deblossoming experiments in the field and greenhouse to determine if presence of developing fruit inhibited the growth of side-shoots in tipworm-injured flowering uprights. We also compared tipworm-injured flowering and vegetative uprights to determine if growth form of an upright influenced regrowth after injury. Removal of flowers from tipworm-injured flowering uprights increased the production of side-shoots in three cultivars of cranberry (Ben Lear, Howes, and Stevens). In addition, more tipworm-injured vegetative uprights resumed growth by producing side-shoots, as compared with flowering uprights (Howes and Stevens). Our results suggest that unequal partitioning of resources between developing fruit and lateral axillary buds inhibits regrowth in tipworm-injured flowering uprights of cranberry.

The objective of this study was to compare the honey yields of groups of honey bee (Hymenoptera: Apidae) colonies with high and low infestation rates of the mite Varroa destructor Anderson and Trueman (Acari: Varroidae). More than 150 colonies were screened for mite fall in early spring and again 16 weeks later. The 10 colonies with the lowest rates (L) and the 10 colonies with the highest rates (H) of mite population growth were selected. These 20 colonies were evaluated for mite infestation in adult bees and honey production. Adult bee infestation in the colonies of the H group was significantly higher than in the colonies of the L group. Additionally, H and L colonies differed significantly for honey production. L colonies produced 28.91 ± 2.34 kg of honey per hive versus 18.49 ± 0.77 kg for the group of H colonies. Furthermore, the mite infestation level of colonies measured as mite fall or as number of mites per 100 bees, was significantly correlated with honey production (r = −0.62, P < 0.05 and r = −0.76, P < 0.01, respectively). These results indicate that varroa mite populations significantly reduce honey yields in honey bee colonies in eastern Canada.

The sunflower stem weevil, Cylindrocopturus adspersus LeConte (Coleoptera: Curculionidae), reduces sunflower, Helianthus annuus Linnaeus (Asteraceae), yields by spreading pathogens, damaging vascular tissues, and promoting lodging of sunflower plants. To assess weevil populations for host plant resistance and insecticide field trials, larvae are dissected out of stems and counted; a process that is slow and limits experimental designs. To improve efficiency of sunflower stem weevil sample processing, field-collected sunflower samples were used to evaluate whether digital radiographs (X-rays) of stem sections or population estimates from rearing out overwintering stem weevils are suitable substitutes for dissection of complete stems. Digital X-rays of small stem pieces (15 cm above soil level) split longitudinally were found to explain over 75% of the variation in numbers of weevil larvae from dissected stem samples (50 cm), but required less than one-fifth the time of manual dissection. Use of small emergence boxes to estimate weevil populations was similarly time efficient, but may not be easily related to weevils per plant because of parasitism and other mortality. Results suggest for large field trials with sunflower stem weevils, digital X-rays provide much more time-efficient larval population estimates.

Ground beetles common in temperate agroecosystems are predators of crop pests, including slugs (Gastropoda: Pulmonata). Salad green production in greenhouses during autumn and spring can be limited by damage due to slugs and other pests. Introducing ground beetles to greenhouses may help reduce damage and improve yields. In the laboratory, while arenas with only slugs produced nearly no harvestable leaves, the presence of Carabus nemoralis Müller (Coleoptera: Carabidae) increased the number and weight of harvestable leaves to 55% of the amount in control arenas (without slugs or beetles), in addition to reducing the number of slugs. In a second experiment, adult or second-instar Pterostichus melanarius (Illiger) (Coleoptera: Carabidae) were released into greenhouse mesocosms (75 cm diameter steel rings) containing salad greens and slugs. Neither adults nor larvae improved the number or weight of harvestable leaves at the first two harvests, and there was no evidence of slug consumption. Towards the end of the experiment cutworms were common in the mesocosms and contributed to damaging salad greens. Adult P. melanarius likely consumed some cutworms, resulting in small increases in salad green yields at the third harvest. Our results suggest that ground beetles should be further examined as part of an integrated approach to pest control in late and early season salad green production in greenhouses.

Knowledge of the effects of variables that can influence trapping results should help to optimise efforts in exotic species detection and other surveys. Two vertical trap placements (understorey, canopy) were tested to determine influence of these two heights on captures of Scolytinae (Coleoptera: Curculionidae), Cerambycidae (Coleoptera), and Siricidae (Hymenoptera) using semiochemical-baited multiple-funnel traps. Traps were baited with α-pinene, ethanol, ipsdienol, and ipsenol. A total of 8463 insects from 65 species and one genus were captured during the study. Average species richness, species diversity, abundance, number of unique species, and expected diversity were higher in understorey compared with canopy traps. Jaccard (0.94 ± 0.05) and Sørensen abundance (0.97 ± 0.03) similarity indices suggested highly similar communities sampled at the two trap heights. Dendroctonus valens LeConte, Dryocoetes autographus Ratzeburg, Hylastes opacus Erichson, Orthotomicus caelatus (Eichhoff), Gnathotrichus materiarius (Fitch), Asemum striatum (Linnaeus), Monochamus scutellatus scutellatus (Say), Rhagium inquisitor (Linnaeus), and Xylotrechus sagitattus sagitattus (Germar) were more abundant in understorey traps. In contrast, Ips pini (Say), Pityogenes hopkinsi Swaine, Monochamus carolinensis (Olivier), Acmaeops proteus (Kirby), and Astylopsis sexgutatta (Say) were more abundant in canopy traps. The common practice of trapping in the understorey may be optimal for sampling arboreal insects as part of survey efforts. However, additional species may be found by trapping at other vertical placements.