Eriocampa ovata (Linnaeus) (Hymenoptera: Tenthredinidae), commonly known as woolly alder sawfly, is an introduced species to North America. Its larvae have six or more prolegs, a brown spot on the head’s vertex, and are woolly in appearance due to a wax secretion from epidermal glands. The author was contacted about six recently planted alder trees in Winnipeg and Victoria Beach, Manitoba, Canada. The trees were determined to be Alnus hirsuta ‘Harbin’ (Betulaceae) (Prairie HorizonTM Manchurian alder), a tree species that has recently gained popularity in Manitoban urban forestry. The defoliation was determined to be caused by larvae of E. ovata. This is the first published record of E. ovata in Manitoba and the first published record of E. ovata on A. hirsuta. This detection should inform pest inventories for E. ovata in Manitoba and provide the basis for a critical examination of biosecurity measures for A. hirsuta.

The functional response of parasitoids is a main component of models that describe host–parasitoid interactions. When the functional response assumed in a model (e.g., a population model) is inaccurate, predictions by the model based on the functional response also become unreliable. This study reports that conventional functional response models may commonly fail to capture the actual functional response of parasitoids and discuss its implications. To assist the discussion, an experiment was conducted to describe interactions between the pupal parasitoid Dirhinus giffardii (Hymenoptera: Chalcididae) and its host Bactrocera dorsalis (Diptera: Tephritidae) in the laboratory. Results showed that the parasitoids typically interacted with all hosts in the environment but parasitised a small fraction of them (e.g., most encountered hosts were rejected), which deviates from the assumption of mechanistic functional response models. An increasing number of published studies on functional response also suggest (although circumstantially) the rejection of unparasitised hosts is common, suggesting that this behaviour is widespread among parasitoid species. By using the experimental results, the study discusses why existing hypotheses are insufficient for the observed behaviour and the implications of this behaviour within the realm of theories surrounding host–parasitoid interactions.

We examine the fossil weaver ants (Formicidae, Formicine, Oecophyllini) of the early Eocene Okanagan Highlands fossil localities of British Columbia, Canada and Washington, United States of America, naming Eoecophylla quilchenensis n. gen. et sp. from Quilchena (British Columbia), formally transferring Camponotites kraussei Dlussky and Rasnitsyn (Republic, Washington) to the genus Oecophylla Smith, F., and describing but not naming a worker (McAbee, British Columbia), treated as Oecophyllini sp. A. These are the oldest known Oecophyllini (Oecophylla + Eoecophylla) and Oecophylla. Forewing vein stubs of E. quilchenensis and its well-developed hind wing vein M are plesiomorphies; this M is unique within the subfamily, suggesting Oecophyllini is sister to other Formicine. The head shape of O. kraussei n. comb. indicates a close relationship to Oecophylla longiceps Dlussky from Eocene Messel, Germany. The ant Titanomyrma Archibald et al. is also known from the Okanagan Highlands and Messel, consistent with Late Cretaceous/early Paleogene intercontinental dispersal. We discuss possible host plants and trophobionts of these ants. Although Okanagan Highlands localities were cooler than the Paleotropical range of modern Oecophylla, their presence there might be explained by mild winters without significant frost.

The blow flies (Diptera: Calliphoridae) include many species that are important as nuisance flies, disease transmitters, and pollinators and are also very important in forensic entomology. Understanding the presence, phenology, and abundance of species in a given area is important in analysing a forensic case and is also valuable in developing baseline databases for comparison over time. Little work on Calliphoridae has been conducted in Manitoba, Canada. Baited traps were deployed at eight sites around the Winnipeg area throughout the insect season in 1978, 1979, and 1980. Five species, Cynomya cadaverina (Robineau-Desvoidy), Protophormia terraenovae (Robineau-Desvoidy), Phormia regina (Meigen), Lucilia illustris (Meigen), and L. sericata (Meigen), were regularly collected, with Calliphora spp. Robineau-Desvoidy collected much less frequently. The same species were collected consistently over the years of trapping, although abundance varied greatly even at the same sites.

Dermacentor variabilis and Dermacentor andersoni (Acari: Ixodidae) parasitise the same range of hosts in western Canada and have largely allopatric ranges except for a zone of sympatry in southern Saskatchewan, where these species experience the same environmental conditions. We report herein the discovery of differences in the behaviour of D. variabilis and D. andersoni larvae after they emerge from eggs. A behavioural diapause observed in D. variabilis larvae was not detected in D. andersoni larvae that were exposed to the same environmental conditions. As unfed D. variabilis larvae can successfully overwinter, their behavioural diapause represents an adaptive strategy to synchronise their questing activity and life cycle stage to maximise the chance of larvae encountering a suitable rodent host at the onset of spring. Such strategy will be of a significant benefit for colonising individuals at the northern edge of the distributional range of D. variabilis.

We explored ecological aspects of the early establishment of the association between the Japanese beetle, Popillia japonica (Newman) (Coleoptera: Scarabaeidae), and the adult tachinid parasitoid, Istocheta aldrichi (Mesnil) (Diptera: Tachinidae), in the province of Québec, Canada. The Japanese beetle started its invasion in the late 1930s, whereas I. aldrichi was detected only in 2009. It is assumed that I. aldrichi spread in the province from its introduced range in the northeastern United States of America. Throughout the summer, we used baited traps in eight localities of southern Québec (2018–2019) and in 13 raspberry (Rubus idaeus) fields (2022) localised along a latitudinal gradient to describe the distribution and seasonal occurrence of both species and the parasitism rates of I. aldrichi. We also mapped observational data from the online platform iNaturalist to further describe the current distribution of both the host and its parasitoid. Results indicate that I. aldrichi is well spread in southern Québec and along the St. Lawrence River in most areas where the Japanese beetle is present. Parasitism mostly occurs from late June to mid-July, before the peak of Japanese beetle populations, and levels of total seasonal parasitism range from 3.9 to 27.3% across sampled sites. Together, trap captures and data from iNaturalist provide evidence that I. aldrichi is now established in most areas of the province of Québec where the Japanese beetle is present.

Thrips (Thysanoptera: Thripidae) communities in agroecosystems are poorly known, particularly in Québec, Canada, where thrips can cause damage in strawberry crops. The phenology of anthophagous thrips and their use of cultivated and wildflower resources were monitored in strawberry agroecosystems, encompassing strawberry (Rosaceae) fields and adjacent uncultivated margins, on Orléans Island, Québec, Canada. A community comprised of 11 thrips species was described, dominated during the whole season by pest species Frankliniella tritici and F. intonsa, which is a first mention in Eastern Canada. Surprisingly, the major strawberry pest F. occidentalis was absent in our samples. Thrips species richness and abundance on wildflowers varied, with few flowering plant species supporting a majority of the community. Sampling sites and local wildflower presence influenced the thrips species assemblage observed on strawberry crops. Such a high thrips diversity was unexpected in this agroecosystem. The identified associations between pest thrips and wildflower species will be useful to develop better control programmes in strawberry crops.

Thirty-one species of Cinara Curtis (Hemiptera: Aphididae) are recorded from Japan, including five that are undescribed. We here formally describe one of the five, Cinara stigmatica sp. nov., from viviparous apterous females on two species of Abies Miller (Pinaceae). Morphological and molecular diagnoses are provided. Specimen data are simultaneously published in an open-access machine-readable format.

The forest tent caterpillar, Malacosoma disstria Hübner (Lepidoptera: Lasiocampidae), is an irruptive forest pest found throughout North America. Widespread species such as M. disstria are exposed to historical and contemporary processes that are not uniform and can generate regionally distinct genomic variation. Previous analyses used a short mitochondrial fragment to infer broad-scale phylogeographic patterns in M. disstria, whereas nuclear markers have been previously applied only in a smaller geographic region. In this study, we quantified M. disstria population variation with genome-wide single nucleotide polymorphisms and cytochrome c oxidase from mitochondrial DNA. Using highly variable genome-wide markers, we resolved clear genomic differences among populations of M. disstria east of the Rocky Mountains that were not detected using mitochondrial variation alone. We also did not detect host-associated divergence in either our genomic or mitochondrial data. Our results highlight the utility of genome-wide markers to resolve intraspecific population structure within a widespread species and support the need for further biogeographic sampling of this forest insect pest.

Forensic entomology is an important component of criminal investigations, providing information surrounding a death using region-specific data on the local necrophagous community. To understand the community within the Metro Vancouver region of British Columbia, Canada, a field study monitored the abundance and diversity of necrophagous Calliphoridae (Diptera) over a nine-month period in distinct terrestrial environments. Baited bottle traps (n = 9) were deployed weekly for 12-hour intervals in three different environments. Species, sex, and gravidity of collected specimens were determined. Bivariate analyses revealed significant relationships between species, geographic location, and month of collection, suggesting that Calliphoridae species composition is influenced by habitat type and seasonal shifts in temperature. Sex ratios and reproductive ranges of Calliphoridae differed among the habitats sampled.

For solitary bees, nesting substrate availability may limit population growth. Here, we investigate the nesting of a locally abundant bee Osmia conjuncta Cresson (Hymenoptera: Megachilidae) in empty shells of exotic snails, Cepaea spp. Held (Stylommatophora: Helicidae), in Hamilton, Ontario, Canada. A literature review determined that O. conjuncta was sparsely distributed throughout its range, with a low relative abundance except for the Niagara Region of Ontario, Canada, three sites in Maryland, United States of America, and the focal study area in Hamilton, Ontario. The Hamilton field survey of five grassland bee communities found O. conjuncta to be the most abundant bee species. The average relative abundance was 18.7%, peaking at 87% on one spring day. A survey of 1088 empty snail shells was done at the site with the highest O. conjuncta abundance. It revealed an average of 10.87 empty shells per square metre with cocoons in 9.8% of the shells, averaging 1.6 cocoons per nest. The relation between shell traits and cocoon presence indicated that O. conjuncta preferred nesting in shells with intermediate size and colour and avoided shells near shrubs. The presence of Cepaea snails increased O. conjuncta populations with potential consequences to the local bee assemblage.

We evaluated the diversity and spatiotemporal emergence patterns of parasitoid wasp species in the genus Eurytoma Illiger (Hymenoptera: Eurytomidae) associated with leaf galls induced by Diplolepis variabilis Bassett (Hymenoptera: Cynipidae) throughout the Okanagan Valley, British Columbia, Canada. We collected D. variabilis galls throughout the region, recorded adult Eurytoma emergence times, extracted mitochondria DNA from a subset of the emergents, and used cytochrome c oxidase 1 and cytochrome b amplificons to assign sampled individuals to species. We also assayed for the bacterial endosymbiont Wolbachia to evaluate the incidence of thelytoky in Eurytoma. Eurytoma showed an extended emergence period and a significant right skew in male emergence. We recorded six Eurytoma species, one of which appears to be previously undescribed. The greatest diversity of Eurytoma species occurs in the north of the sampled area. Five of the six species showed Wolbachia infection in at least some individuals, and the most abundant and widespread species, Eurytoma imminuta Bugbee, showed high Wolbachia infection levels and an all-female population, which strongly indicates endosymbiont-induced thelytoky. Our results demonstrate that gall communities are locally variable, and we suggest that future studies be undertaken to quantify variation in community composition at more local scales than has been past practice.

Intermittent streams that periodically cease surface flow have long been understudied in ecology and underrepresented in conservation policy. However, they currently account for 30–50% of the global river network, and that number is rising due to anthropogenic water extraction, land-use change, and climate change. We explored the Coleoptera biodiversity of the south Pacific coast region of British Columbia, Canada, using pitfall traps at perennial and naturally intermittent stream reaches, in shoreline, dry streambed, and riparian habitats, in both flowing (spring and early summer) and nonflowing (late summer) phases. We found that habitats around perennial reaches had significantly greater abundance of Coleoptera individuals than did those around intermittent reaches. However, neither habitat type nor flow regime was a significant predictor of taxon richness, and intermittent stream sites featured unique taxa that were not found near perennial streams. This aligns with recent results from other taxonomic groups; that is, finding that intermittent ecosystems can host high taxonomic diversity of Coleoptera, on par with or even greater than that of perennial streams. Because intermittent streams will likely become more prevalent within the global river network, a better understanding of how different species use these habitats is needed to inform appropriate biodiversity conservation efforts and flow management.

Relatedness within groups is influenced by the mating patterns of founders: the more parents that contribute to a group, the lower the relatedness of their offspring. Xylocopa virginica (Hymenoptera: Apidae) is a facultatively social bee in which low relatedness is influenced by sequential maternity. We investigated whether multiple paternity, which would occur if egg-laying females mate multiple times, might also contribute to low relatedness among female nestmates. We used two approaches to investigate how frequently females mate polyandrously. First, we used visual observations of mating behaviour to estimate mating frequencies and to evaluate evidence for temporal variation in female receptivity to mates. Second, we used a data set of microsatellite genotypes to evaluate evidence for multiple paternity based on inferred proportions of full and half sisters. Based on visual observations, we inferred a female mating frequency of 1.1 (harmonic mean). Females were more receptive early in their first nestmate provisioning phase and less receptive in their second brood provisioning phase. Based on microsatellite genotypes analysed with COLONY software, we inferred that 5–44% of female sibships included maternal half sisters, implying female mating frequencies between 1.13 and 1.41 (harmonic means). Thus, multiple mating contributes to the low group relatedness found in Xylocopa virginica.

Narrow-spectrum insecticides are currently used to control populations of spruce budworm, Choristoneura fumiferana Clemens (Lepidoptera: Tortricidae), in eastern Canada. However, these could have nontarget impacts on other caterpillars – some of which may serve as alternative or alternate hosts to key parasitoids – that are also susceptible to control tactics. This study was conducted to determine how the insecticides, Bacillus thuringiensis variety kurstaki (Btk) and tebufenozide, used to control spruce budworm populations, impact caterpillar communities and associated parasitism rates. Post-treatment field sampling of caterpillars was conducted in 2018 and 2019 in New Brunswick, Canada, at sites treated with either Btk or tebufenozide and at control sites. Caterpillar species richness and abundance, community structure, and parasitism rates were assessed using molecular analyses for 659 collected caterpillars. We found that insecticide applications had no significant impact on abundance, species richness, or parasitism rate relative to the measurements made in the control sites. Nonetheless, a significantly higher caterpillar abundance and lower parasitism rate occurred in Btk-treated sites than in tebufenozide-treated sites. Overall, however, Btk and tebufenozide treatments did not negatively affect the non-budworm caterpillar community under the present conditions of low caterpillar densities, suggesting that parasitoids have alternative and alternate hosts after treatments that target the spruce budworm.

The swede midge, Contarinia nasturtii (Kieffer) (Diptera: Cecidomyiidae), is invasive to North America, where it was first reported in Ontario, Canada. It is now established in eastern Canada and from eastern Minnesota in the Midwest to the northeastern seaboard of the United States of America. Swede midge is a serious pest of brassicaceous plants, including vegetable and oilseed crops. To ensure its early detection in the Northern Great Plains, a monitoring programme was established using pheromone traps located primarily along the edges of canola fields from North Dakota, United States of America, northwest to the Peace River region, in Alberta and British Columbia, Canada. In North Dakota, 117 trap sites were monitored between 2015 and 2021. In western Canada, monitoring occurred on a small scale from 2006 to 2011, and 521 trap sites were monitored from 2013 to 2021. Swede midge was not detected in canola grown in the Northern Great Plains between 2006 and 2021. Partners in North Dakota and western Canada intend to maintain the monitoring programme to support early detection of swede midge if it does continue to disperse northwestwards. The monitoring programme contributes to outreach activities and fosters farmer and agronomist participation in pest management (i.e., community science) in the Northern Great Plains.

We examine the implications for intercontinental dispersal of the extinct ant genus, Titanomyrma Archibald et al. (Hymenoptera: Formicidae: Formiciinae), following the discovery of its first fossil in Eocene temperate upland Canada. Modern Holarctic distributions of plants and animals were in part formed by dispersals across Late Cretaceous through early Eocene Arctic land bridges. Mild winters in a microthermal Arctic would allow taxa today restricted to the tropics by cold intolerance to cross, with episodic hyperthermal events allowing tropical taxa requiring hot climates to cross. Modern ants with the largest queens inhabit low latitudes of high temperature and mild coldest months, whereas those with smaller queens inhabit a wide variety of latitudes and climates. Gigantic and smaller formiciine ants (Titanomyrma and Formicium Westwood) are known from Europe and North America in the Eocene. The new Canadian Titanomyrma inhabited a cooler upland. It is incomplete, indistinctly preserved, and distorted in fossilisation, and so we do not assign it to a species or erect a new one for it. The true size of this fossil is unclear by this distortion: small size would support gigantism in Titanomyrma requiring hot climates and dispersal during hyperthermals; if it was large, it may have been cold-winter intolerant and able to have crossed during any time when the land bridge was present.

We record 392 species or morphospecies of bees (Hymenoptera: Apoidea) for Manitoba, Canada, which is 154 more species than reported in 2015 and includes five new generic records since 2015 (Ashmeadiella, Brachymelecta, Eucera, Neolarra, and Triepeolus). Thirteen new records reported here are new for Canada: Calliopsis (Nomadopsis) australior Cockerell, Perdita (Perdita) tridentata Stevens, Brachymelecta interrupta (Cresson), Diadasia (Dasiapis) ochracea (Cockerell), Melissodes bidentis Cockerell, Nomada crawfordi crawfordi Cockerell, Nomada fuscicincta Swenk, Nomada sphaerogaster Cockerell, Nomada xantholepis Cockerell, Triepeolus cf. grindeliae Cockerell, Dianthidium (Dianthidium) parvum (Cresson), Coelioxys (Xerocoelioxys) nodis Baker, and Megachile (Megachiloides) dakotensis Mitchell. We remove the following species from the list of Manitoba bees based on re-examination of voucher material: Andrena (Ptilandrena) geranii Robertson, Andrena (Rhacandrena) robertsonii Dalla Torre, Andrena (Simandrena) nasonii Robertson, Andrena (Trachandrena) ceanothi Viereck, Andrena (Trachandrena) quintilis Robertson, Lasioglossum (Hemihalictus) pectoraloides (Cockerell), Lasioglossum (Lasioglossum) forbesii (Robertson), and Dianthidium (Dianthidium) concinnum (Cresson). We propose that Nomada alpha paralpha Cockerell, 1921 and N. alpha dialpha Cockerell, 1921 are junior synonyms of N. alpha Cockerell, 1905. Nomada arenicola Swenk, 1912 is considered a junior synonym of N. fervida Smith, 1854. Protandrena albertensis (Cockerell) and Neolarra mallochi Michener are recognised as valid species. We provide additional notes on taxonomy, nomenclature, and behaviour for select species in the list.

Understanding movements of Drosophila suzukii (Diptera: Drosophilidae) into berry fruit crops from wild-fruit hosts in borders of semi-natural agroecosystems, such as lowbush blueberry, is important to determining harvesting time and managing wild-fruit diversity near crops. This study aimed to inventory the wild-fruit hosts associated with lowbush blueberry (Ericaceae) production in Québec, Canada, near the limits of lowbush blueberry’s eastern North American range. We also tested the hypothesis that fruit traits of berry fruit species present in or near lowbush blueberry fields might explain field infestation levels. Flies of both sexes emerged from five wild-fruit species in 2016, to which six more species were added in 2017. The most productive wild-fruit hosts were Cornus canadensis (Cornaceae) and Aralia hispida (Araliaceae) (> 100 emerged flies/100 g of fruit) in 2016, to which Prunus pensylvanica (Rosaceae) and Rubus idaeus (Rosaceae) were added in 2017. Among nine variables considered in statistical modelling (fruit size, sugar content, and reflected colour bands) and taxonomic family (a nominal variable), none could explain field infestation levels over two years. In lab tests comparing fruits of Cornus canadensis, a common weed within fields, and lowbush blueberries, mated D. suzukii females laid twice as many eggs on blueberries, but both species were equally suitable for development.