The male flagellum of 32 North American tiger beetle (Cicindela Linnaeus; Coleoptera: Carabidae: Cicindelinae) species was examined with a scanning electron microscope for new, stable characters that might be useful in studies of taxonomy and functional morphology. Two sets of characters were observed, shape and size of the flagellum, and the form and distribution of tempers (micro teeth-like structures on the surface of the flagellum). These characteristics were surprisingly uniform for most species. It is inferred that the inner walls of the female spermatheca duct are gripped by the male flagellum, achieved either by flexing the inserted temper-free long flagellum, or direct insertion by the temper-covered short flagellum. It is proposed that an inverse relationship pattern exists between the elongate temper-free flagellum, and the temper-covered shorter flagellum.

We collected naturally infested Pinus resinosa Aiton (Pinaceae) and P. sylvestris Linnaeus to investigate phenological patterns and quantify parasitism by a suite of native hymenopteran parasitoids on two woodwasps (Hymenoptera: Siricidae): the invading non-native European woodwasp, Sirex noctilio Fabricius, and a co-colonising native, S. nigricornis Fabricius. We sampled a total of 76 trees from two field sites in 2010 and seven sites in 2011. In raw abundance, S. noctilio outnumbered S. nigricornis by 2:1 in 2010 and by 7.5:1 in 2011. We collected the egg/early instar parasitoid, Ibalia leucospoides ensiger Norton (Hymenoptera: Ibaliidae); four species of Rhyssinae (Hymenoptera: Ichneumonidae) late larval parasitoids; and Pseudorhyssa nigricornis (Ratzeburg) (Hymenoptera: Ichneumonidae), a cleptoparasitoid of rhyssines. Variation in siricid and parasitoid species assemblage and abundance was explained primarily by site, with tree-level factors playing a secondary role. Parasitism was significantly lower in P. sylvestris (13.6%±4.1 SE), a naturalised pine from Europe, than in the native P. resinosa (28.5%±5.0). Total parasitism was 27.6%±5.0 in 2010 and 20.9%±4.7 in 2011. This study represents the most robust analysis of the diverse woodwasp and parasitoid assemblage infesting pines in North America.

Movement between host plants during the growing season is a common behaviour among insect herbivores, although the mechanisms promoting these movements are poorly understood for many systems. Two possible reasons why insect herbivores relocate include compensating for host plant quantity and/or quality changes and the avoidance of natural enemies. The Arctic caterpillar (Gynaephora groenlandica (Wocke); Lepidoptera: Lymantriidae) moves several metres each day, feeds on its patchily distributed host plant, Arctic willow (Salix arctica Pallas; Salicaceae), and has two main natural enemies, the parasitoids Exorista thula Wood (Diptera: Tachinidae) and Hyposoter diechmanni (Nielsen) (Hymenoptera: Ichneumonidae). We physically moved caterpillars between Arctic willows and restricted other caterpillar individuals each to a single willow throughout the active period of Arctic caterpillars. We found that growth rate, herbivory rate, and the proportion of available leaf fascicles eaten were higher for experimentally moved caterpillars. Parasitoid abundances were low and did not differ between experimentally moved and stationary caterpillars. Taken together, our study addresses the bottom–up and top–down controls on insect herbivore movement during the short duration of the growing season in the Arctic. Our results suggest that caterpillars are likely moving to new willow shrubs to access high quality resources.

Canada has a distinguished history of research in forest entomology. The number of peer-reviewed publications emanating from studies in forest entomology in Canada greatly increased following the Second World War. Much of the outstanding historical success in Canadian forest entomological research is attributable to the work of entomologists employed by the Canadian Forest Service, who authored the majority of studies until the mid 1970s and usually published them in The Canadian Entomologist. Since that time the majority of studies have been published by Canadian universities in a broad range of journals. Most early research in forest entomology in Canada was carried out by men, but since that time the proportion of forest entomological research carried out by women has increased significantly. The majority of research in central and eastern Canada focussed on defoliators and their natural enemies and host plants whereas the majority of research in western Canada examined bark beetles (Coleoptera: Curculionidae: Scolytinae) and their natural enemies and host plants. Although publications on defoliators and their natural enemies have occurred continuously throughout the historical development of forest entomology in Canada, the numbers of publications on wood borers (Coleoptera: Buprestidae, Cerambycidae) and bark beetles and their natural enemies have never been higher than they are presently.

Under laboratory and field conditions in Ontario, Canada, we explored the natural history of Phasgonophora sulcata Westwood (Hymenoptera: Chalcididae), an indigenous solitary endoparasitoid of Agrilus planipennis Fairmaire (Coleoptera: Buprestidae) in North America. Adult P. sulcata emergence was ~20.2–23.9 days after host emergence at 21°C, with P. sulcata females emerging an ~5.4–5.8 days before males. Females also represented 61.8 and 67.0% of emerging adults in the two years sampled. Mean adult longevities for males and females of P. sulcata were 23.8±1.10 and 28.9±1.11 days at 21°C, respectively. Mean potential fecundity of P. sulcata at emergence was 55.7±2.9 eggs per female. Based on adult emergence, parasitism at two sites varied from 11.7% to 34.4%. Adult parasitoids were first observed in the field in early June, with peak capture occurring in late June. Parasitism rates in A. planipennis-infested ash trees was not affected by tree height below 360 cm, whereas parasitism was not observed at heights>360 cm. Our results suggest that although mass rearing will be challenging, observed parasitism rates in conjunction with temporal and spatial synchrony indicate that indigenous P. sulcata may be an important source of mortality for A. planipennis populations.

We evaluated the effect of tree genotype on the resistance of balsam fir, Abies balsamea (Linnaeus) Miller (Pinaceae), to damage from the balsam twig aphid, Mindarus abietinus Koch (Hemiptera: Aphididae), by visually assessing aphid damage in clonal seed orchards located in New Brunswick and Nova Scotia, Canada, during four consecutive years. Estimates of clone mean heritability were moderate, suggesting that heritability of resistance is influenced by genetic factors. In New Brunswick, positive phenotypic and genetic correlations of clone-mean damage among years indicate that clones rank similarly each year. Our results suggest that selectively breeding for increased resistance could result in genetic gains.

Phasgonophora sulcata Westwood (Hymenoptera: Chalcididae) is a North American parasitoid now using Agrilus planipennis Fairmaire (Coleoptera: Buprestidae) as a novel host, and may prove useful in biocontrol. Unfortunately, information is lacking regarding mating and the presence of pheromones, which may be important when attempting to exploit this parasitoid within a management context. Herein we used olfactometer assays and behavioural observations to determine the courtship and mating sequences of P. sulcata. A significantly higher proportion of males oriented towards females over the control arm containing filtered air in an olfactometer regardless of the age classes of females or males examined. We also observed four pre-copulatory behaviours that were consistent in all mating pairs. Our results indicate that courtship may be mediated by male perception of female-produced pheromones. Understanding the courtship sequence may be useful in rearing laboratory populations, while the putative pheromones may be useful in detection and retention of P. sulcata populations.

For quaking aspen (Populus tremuloides Michaux; Salicaceae) the rate of extrafloral (EF) sugar secretion is increased by defoliation and decreased by drought. Although wholesale blocking of EF nectar has been shown to reduce ant (Hymenoptera: Formicidae) visitation to aspen, the effect of more subtle and realistic variations in nectar availability on ant recruitment is unknown. Working in Alaskan boreal forest (United States of America), we reduced and supplemented EF nectar availability on potted aspen ramets of three genotypes and surveyed visitation by free-living Formica fusca (Linnaeus) (Hymenoptera: Formicidae). Ants were more responsive to a subtle increase in sugar availability than to a decrease. While nectar reduction had no effect on ant visitation, nectar supplementation increased ant visitation to one aspen genotype by 70% during an early summer trial. Average ant visitation to different aspen genotypes varied during the late summer, indicating that aspen genotype can influence attractiveness to ants. We conclude that natural induction of EF secretion in response to herbivory may benefit aspen through improved ant recruitment, though the response is dependent on aspen genotype and time of year. Differences among aspen genets in attractiveness to ants could influence the relative success of genotypes, especially in settings in which aspen regenerates from seed.

Infection by Nosema fumiferanae (Thomson) (Microsporidia: Nosematidae) and feeding by late-instars on previous year’s foliage due to depletion of current year’s growth (also known as back-feeding) are likely to co-occur in high-density outbreak populations of the spruce budworm (Choristoneura fumiferana (Clemens) (Lepidoptera: Tortricidae)). We tested the hypothesis that effects of the two factors on larval fitness are exacerbated by their interaction. Twigs of balsam fir (Abies balsamea Linnaeus; Pinaceae) with or without new-growth shoots were fed to sixth-instar offspring from uninfected, moderately infected, or highly infected females in two laboratory experiments. Pupal mass and time to reach the pupal stage were significantly affected by infection and back-feeding but not by their interaction. Pupal mass decreased and development time increased with increasing spore burden in a linear fashion. Back-feeding had a significant effect on survival to the pupal stage, but infection did not, nor did their interaction. The relatively small changes in survival, pupal mass, and development time caused by infection and back-feeding were additive. The results thus refute our hypothesis that infection by N. fumiferanae and forced feeding on last year’s foliage by late instars are likely to interact in affecting spruce budworm recruitment in older outbreak populations.

Seventeen Myodes gapperi (Vigors) (Rodentia: Cricetidae), 13 Peromyscus maniculatus (Wagner) (Rodentia: Cricetidae), 12 Microtus pennsylvanicus (Ord) (Rodentia: Cricetidae), four Zapus princeps Allen (Rodentia: Cricetidae), three Ictidomys tridecemlineatus (Mitchill) (Rodentia: Sciuridae), and eight shrews (Soricomorpha: Soricidae) collected at Blackstrap Lake (BL), and 48 P. maniculatus, 15 Z. princeps, 15 M. pennsylvanicus, and one Sorex monticolus Merriam (Soricomorpha: Soricidae) collected at Saskatchewan Landing Provincial Park (SLPP), in southern Saskatchewan, Canada were examined for ticks. Although no adult ticks were detected on small mammals at either locality, Dermacentor variabilis (Say) (Acari: Ixodidae) larvae (n=144) and nymphs (n=7) were found on four species of small mammal at BL. At SLPP, both D. variabilis larvae (n=71) and nymphs (n=6), and Dermacentor andersoni Stiles (Acari: Ixodidae) nymphs (n=9) were collected from small mammals. Both tick species were present on P. maniculatus and M. pennsylvanicus at SLPP, indicating an overlap in their host range and, hence, the potential for transmission of microorganisms between tick species at sites where they coexist. However, the results of polymerase chain reaction assays used to detect bacteria of the genus Rickettsia da Rocha-Lima (Rickettsiaceae) in ticks, revealed that R. peacockii Niebylski et al. only occurred in nymphs of D. andersoni, whereas no Rickettsia were present in the larvae and nymphs of D. variabilis.

In 1969, Robert E. Gregg collected five species of ants (Hymenoptera: Formicidae) in three Subarctic localities near the town of Churchill, Manitoba, Canada, which he documented in a 1972 publication in The Canadian Entomologist. To determine whether there have been any additions to the local fauna – as might be predicted to occur in response to a warming climate and increased traffic to the Port of Churchill in the intervening 40 years – we re-collected ants from the same localities in 2012. We identified the ants we collected from Gregg’s sampling sites using both traditional morphological preparations and DNA barcoding. In addition, we examined specimens from Gregg’s initial collection that are accessioned at the Field Museum of Natural History (Chicago, Illinois, United States of America). Using this integrative approach we report seven species present at the same sites Gregg sampled 40 years earlier. We conclude that the apparent increase is likely not due to any arrivals from more southerly distributed ants, but to the increased resolution provided by DNA barcodes to resident species complexes with a complicated history. We provide a brief synopsis of these results and their taxonomic context.

Three species of woodpeckers (Piciformes: Picidae) in Manitoba, Canada, were examined for chewing lice (Phthiraptera): the resident downy woodpecker (Picoides pubescens (Linnaeus), n=55), and two migrants, yellow-bellied sapsucker (Sphyrapicus varius (Linnaeus), n=316) and northern flicker (Colaptes auratus (Linnaeus), n=225). Six species were collected: Menacanthus pici (Denny) (Amblycera: Menoponidae) from all hosts, and five species of Ischnocera (Philopteridae): Penenirmus auritus (Scopoli) from downy woodpeckers and sapsuckers, Picicola snodgrassi (Kellogg) and Brueelia straminea (Denny) from downy woodpeckers, and Penenirmus jungens (Kellogg) and Picicola porisma Dalgleish from flickers. Adults and nymphs were present on downy woodpeckers all year, and on migrant sapsuckers and flickers from when they arrived until they left, suggesting lice reproduce continuously on their hosts. Prevalence and mean intensities of louse infestations generally decreased from their respective springtime levels to their lowest values during or at the end of the breeding season of their hosts, and then increased in various degrees during the fall. No seasonal pattern in louse sex ratios was observed except on northern flickers, where male to female ratios for two of three species were lowest during the breeding season. Resident and migrant hosts had similar seasonal patterns of infestation by lice.

The invasive woodwasp Sirex noctilio Fabricius (Hymenoptera: Siricidae) is obligately associated with the symbiotic white rot fungus Amylostereum areolatum (Chaillet ex Fries) Boidin (Basidiomycota: Amylosteraceae), and shows positive chemotaxis to volatiles emitted by this symbiont. After introduction to North America, S. noctilio was collected carrying another fungus species Amylostereum chailletii (Persoon) Boidin, used symbiotically by native North American Sirex Linnaeus. We conducted flight behaviour studies in a walk-in flight tunnel to evaluate specificity of the attraction of mated and unmated S. noctilio to its primary symbiont, A. areolatum, versus the alternative symbiont, A. chailletii. Fewer unmated than mated S. noctilio females responded to either of the fungi. Unmated females showed no landing preference but mated S. noctilio females were attracted to A. areolatum although avoidance of A. chailletii was not complete. Chemical analysis demonstrated major differences in the volatile profiles of the two fungal species. Sesquiterpenes dominated the A. areolatum samples, whereas only two aromatic volatiles were consistently present in the native A. chailletii.

The comparative ecology of conifer-feeding budworms in the genus Choristoneura Lederer (Lepidoptera: Tortricidae) in Canada is reviewed with emphasis on publications since 1980. Systematics and life history are updated and historical outbreak patterns and their current interpretation summarised. Recent evidence is analysed in the context of ecological interactions among three trophic levels; host plant, budworm herbivore, and natural enemies. The influence of weather and climate are viewed as modulating factors. The population behaviour of budworms is interpreted as the result of tri-trophic interactions that vary at different scales. The result of these multi-scale interactions is that despite shared phylogenetic constraints and common adaptations, different budworm species display different population behaviour because of specific ecological relationships with their respective hosts and natural enemies.

The tomato leafminer, Tuta absoluta Meyrick (Lepidoptera: Gelechiidae), is a widespread devastating pest reported to develop on economically important solanaceous crops. The characterisation of its host range could help to understand and prevent the dispersion behaviour of the insect in the environment. In this study, the ability of T. absoluta to develop on 12 cultivated or non-cultivated plants including Solanaceae, Amaranthaceae, Convolvulaceae, Fabaceae, and Malvaceae species under laboratory conditions was assessed. For each plant species, we monitored the development times of immature stages, survival, sex ratios, and adult fecundity rates. All the six tested non-solanaceous plants, including Chenopodium Linnaeus (Amaranthaceae), Convolvulus Linnaeus (Convolvulaceae), and Malva Linnaeus (Malvaceae) species, were not able to sustain (i.e., allow growth and development) T. absoluta larvae. Solanum Linnaeus (Solanaceae) species were the most suitable host plants for the pest, but others could be opportunistically colonised with fewer incidences. Tuta absoluta appears to be strongly related to solanaceous plants that would predominantly support self-sustaining field populations. Preventing crop infestation by removing potential host plants in the immediate field vicinity and culture rotations with non-solanaceous crops is of primary importance.

Oak twig pruner (Anelaphus parallelus (Newman); Coleoptera: Cerambycidae) larvae develop inside twigs pruned from host plants. Reasons for this behaviour are unknown and differential emergence due to twig diameter has not been explored. Twigs pruned from walnuts (Juglans nigra Linnaeus; Juglandaceae) (n=179) and oaks (Quercus Linnaeus; Fagaceae) (n=84) were collected in Pennsylvania, United States of America in 2010; 118 pruned oak twigs were collected in New York State, United States of America in 2012. Twigs from 2012 were dissected to determine rates of emergence and larval mortality; both samples were examined for parasitoids. As the diameter of oak twigs (range of 3–16 mm) increased, larval mortality increased and adult emergence decreased. Date of collection did not influence twig diameter nor emergence rates. Three new parasitoids were associated with the oak twig pruner: Atanycolus Förster (Hymenoptera: Braconidae), Eubazus denticulatus (Martin) (Hymenoptera: Braconidae), and a potentially new genus of wasp (Hymenoptera: Braconidae, Hormiinae near Pambolus Haliday). Parasitism rates were an order of magnitude greater among twigs that contained more than one larva or pupa (23.1%; n=26) compared to those that contained only one (2.3%; n=341).

The emitted aliphatic hydrocarbon profile of four Indian Coccinellidae (Coleoptera), Coccinella septempunctata (Linnaeus) (C7), Coccinella transversalis Fabricius (Ct), Menochilus sexmaculatus (Fabricius) (Ms), and Propylea dissecta (Mulsant) (Pd) has been investigated by simple solvent-less headspace solid-phase microextraction (HS-SPME) technique coupled with gas chromatography and mass spectroscopy (GC-MS). Identified volatile and non-volatile compounds were confirmed by running corresponding standards and comparing with the National Institute of Standards and Technology library. Among the 56 identified aliphatic hydrocarbons, saturated aliphatic hydrocarbons were more in number than unsaturated ones. Among saturated hydrocarbons, methyl branched hydrocarbons were more in number in C7 and Ct than Ms and Pd. Menochilus sexmaculatus and Pd had higher percentages of unsaturated hydrocarbons than C7 and Ct. Among branched chain-hydrocarbons, mono-methylated saturated hydrocarbons were more in number than dimethylated saturated hydrocarbons. Further analysis of the semiochemical profile revealed a closeness between C7 and Ct, and between Ms and Pd. Quantitative analysis revealed that straight chain hydrocarbons form separate clusters to branched chain methylated hydrocarbons. This is the first attempt to identify the semiochemical profile of some Indian coccinellids using the headspace solid phase micro-extraction technique coupled with the gas chromatography-mass spectrometry technique. This report will be helpful for various chemotaxonomic studies of the species in the future.

Russian olive (Elaeagnus angustifolia Linnaeus; Elaeagnaceae) is an exotic shrub/tree that has become invasive in many riparian ecosystems throughout semi-arid, western North America, including southern British Columbia, Canada. Despite its prevalence and the potentially dramatic impacts it can have on riparian and aquatic ecosystems, little is known about the insect communities associated with Russian olive within its invaded range. At six sites throughout the Okanagan valley of southern British Columbia, Canada, we compared the diversity of insects associated with Russian olive plants to that of insects associated with two commonly co-occurring native plant species: Woods’ rose (Rosa woodsii Lindley; Rosaceae) and Saskatoon (Amelanchier alnifolia (Nuttall) Nuttall ex Roemer; Rosaceae). Total abundance did not differ significantly among plant types. Family richness and Shannon diversity differed significantly between Woods’ rose and Saskatoon, but not between either of these plant types and Russian olive. An abundance of Thripidae (Thysanoptera) on Russian olive and Tingidae (Hemiptera) on Saskatoon contributed to significant compositional differences among plant types. The families Chloropidae (Diptera), Heleomyzidae (Diptera), and Gryllidae (Orthoptera) were uniquely associated with Russian olive, albeit in low abundances. Our study provides valuable and novel information about the diversity of insects associated with an emerging plant invader of western Canada.

Wheat midge, Sitodiplosis mosellana (Géhin) (Diptera: Cecidomyiidae), Palaearctic in origin, is thought to have been introduced into North America in the early 1800s. It is a major pest of spring wheat (Triticum aestivum Linnaeus (Poaceae)), durum wheat (T. durum Desfontaines), triticale (X-Triticosecale), and, to a lesser extent, spring rye (Secale cereale Linnaeus (Poaceae)) throughout the northern Great Plains. Climate is the principal factor regulating the distribution and abundance of most insects. A bioclimate simulation model was developed to explain the current distribution and abundance of S. mosellana. The current distribution for North America, Europe, and Asia was consistent with model projections. General circulation model scenarios (CSIRO-MK 3.0 and MIROC-H) for the 2030 and 2070 time periods were applied to the bioclimate simulation model of S. mosellana to assess the potential impact of changing climates on their distribution and relative abundance. Potential changes to relative abundance and distribution were most sensitive to time period, as opposed to climate change scenario. Differences between the MIROC-H and CSIRO-MK 3.0 models were restricted to particular regions in North America. The study found that the range and abundance of S. mosellana, and associated crop risk, was predicted to expand in a northerly direction and contract across the present southern limits.

Our review highlights research during the past century focussed on the population ecology of outbreak-prone insect defoliators in Canadian forests. Based on reports from national and provincial surveys that began in the 1930s, there have been at least 106 insect defoliators reported to outbreak, most of which are native Lepidoptera, Hymenoptera (sawflies), or Coleoptera (in order of frequency from most to least). Studies comparing life-history traits of outbreak versus non-outbreak species to better understand why certain species are more outbreak-prone indicate several traits especially common among outbreak species, including egg clustering and aggregative larval feeding. There have been at least 50 time-series studies examining the spatiotemporal population behaviour of 12 major defoliator species. These studies provide evidence for both regular periodicity and spatial synchrony of outbreaks for most major species. Life-table studies seeking to understand the agents causing populations to fluctuate have been carried out for at least seven outbreak species, with the majority identifying natural enemies (usually parasitoids) as the major driver of outbreak collapse. Our review concludes with several case studies highlighting the impact and historical underpinnings of population studies for major defoliator species and a discussion of potential avenues for future research.