Canola, Brassica napus Linnaeus var. oleifera, is one of the main oilseeds grown in the world. Pollination is required to ensure an acceptable yield. Among the main bee pollinators (Hymenoptera: Apidae) occurring in canola in southern Brazil are Apis mellifera (Linnaeus) (Apidae: Apini) and Trigona spinipes (Fabricius) (Apidae: Meliponini). Plant genotype, sowing season, meteorological factors, and abundance of competitors can influence the foraging rate of A. mellifera and T. spinipes in canola, which will impact yield. We evaluated the effect of plant genotype, sowing season, and meteorological factors on the abundance of foraging bees, as well as their coabundance and impacts on canola yield. Under the conditions of the study, we did not observe significant variation between genotypes and sowing season on bee abundance and canola yield. We note that the impact of temperature and relative humidity are important predictors of abundance of A. mellifera and T. spinipes. The temperature and relative humidity effects, however, differed according to bee species. Coabundance patterns indicated no evidence of competitive exclusion. Higher canola yields were obtained when both bee species had high population abundance.

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.

Cephus cinctus Norton (Hymenoptera: Cephidae), the wheat stem sawfly, is a well-established and important pest of wheat, Triticum aestivum Linnaeus (Poaceae), and its relatives in North America. Crop losses are caused directly by C. cinctus feeding inside wheat stems during larval development and indirectly when weakened plants lodge before being harvested. Understanding the factors that affect population dynamics of C. cinctus can help farmers to better manage it. Our study therefore explored how C. cinctus and natural enemy densities vary in space (southern Alberta, Canada) and over time. Five fields were sampled using an established protocol in fall 2019 and resampled in spring 2020; six additional fields were sampled in fall 2020 and resampled in spring 2021. Wheat stubs were dissected to record numbers of cut stems, C. cinctus larvae, and sources of larval mortality (i.e., parasitism, fungal infection). Densities of wheat stem sawfly and the impact of natural enemies varied between the sampled fields. No C. cinctus mortality was observed during the winter, indicating that C. cinctus population dynamics are not susceptible to mortality (abiotic or biotic) between years. Results of our study will be incorporated into new models to predict wheat stem sawfly phenology and risk to crop production.

Parthenium hysterophorus Linnaeus (Asteraceae), commonly known as “congress grass,” is among the 10 worst weeds of India and is considered one of the world’s 100 most harmful invasive species. This species has been introduced accidentally into several countries, including India, and is a major agricultural and rangeland weed in more than 45 countries. It affects crop production, suppressing biodiversity, crop yields, the health of farm animals and human beings, and local and regional economies. Biological control has been found to be a cost-effective management strategy to control the weed, with the leaf beetle, Zygogramma bicolorata Pallister (Coleoptera: Chrysomelidae), considered an effective and safe biocontrol agent. Several studies have investigated the beetle’s biology, reproduction, and other life attributes. This review compiles the existing information about Z. bicolorata biology, growth, development, reproduction, food, and host specificity, and the effects of abiotic and biotic stressors on the insect’s life attributes. We anticipate that this review will helpful for improving strategies for this bioagent’s swift mass rearing and for developing classical biological control design for Parthenium weed.

There is strong evidence that a biodiversity crisis is underway, fuelled by pollution, climate change, and invasive species. These impacts are especially important in northern Canadian regions. However, insect and other arthropod monitoring in Northern Canada urgently needed for land preservation is lacking. This paper presents the Nunavik Sentinels, a community-based participatory research programme (see definition, Table 1), that is aiming to fill those knowledge gaps while promoting collaboration among all stakeholders (organisations and members of northern communities, and scientists). Nunavik Sentinels is a unique insect-monitoring programme facilitated by the Montréal Insectarium – Espace pour la vie (Montréal, Québec, Canada), making entomology accessible to Indigenous youth by providing them with tools to lead expeditions in unexplored habitats and involving them in data collection. We present how this programme came to existence and its four-pillar framework (i.e., training land camp, summer employment, educational kit, and research). We touch upon how the programme is continually evolving. Finally, we demonstrate the benefits of the programme and how it will help better define the actions to be taken to prepare for future changes in northern biodiversity.

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.

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.

I review the history of forest tent caterpillar, Malacosoma disstria (Hübner) (Lepidoptera: Lasiocampidae), occurrence from 1938 to 2001 throughout Canada, with emphasis on the insect’s impact on tree mortality. I show that forest tent caterpillar routinely kills a portion of its host tree population during outbreaks. Although the proportion killed is typically small, there are some unusual conditions during which the foliage grazer can precipitate large-scale host forest declines. These decline episodes are the result of a spatially complex pattern of outbreak spread whereby successive cycles occur asynchronously enough that there is a zone of overlap where the two cycles occur in rapid succession, leading to three to six years of defoliation, triggering a nonlinear mortality response that endures through time. One of these “cycles” is typically amplified locally to an intensity that is anomalously high and nonrecurring. Defoliation events that are periodic in aggregate may thus give rise to patterns of insect-caused forest decline that are episodic. These decline events have been shifting northwards over time and have been growing in extent. The dynamics of outbreak occurrence appears to be a complex result of interacting top–down and bottom–up forces, making it challenging to predict in advance whether or not any given outbreak will exceed the threshold required to precipitate large-scale mortality.

Using aerial sketch map data spanning more than 1 000 000 km2 across Canada, I use cluster analysis to show that outbreaks of forest tent caterpillar, Malacosoma disstria Hübner (Lepidoptera: Lasiocampidae), through the 20th century have occurred regularly every decade or so; however, there are two distinct aspects to the patterning of outbreaks. The dominant mode of variability is a nonrecurring pattern of singular spike anomalies, lasting just a few years, that are regional in extent but are not synchronised across the country. The regional time series derived from cluster analysis that are dominated by these singular spike eruptions exhibit extreme skewness and kurtosis, are not stationary in mean or variance, and are not amenable to classical time-series analysis. Although these regional-scale eruptive anomalies tend to occur periodically in aggregate, their central location always varies in an unpredictable manner, resulting in aperiodic local behaviour. Range-wide periodicity is thus an emergent property from asynchronous, aperiodic eruptions aggregated across regions. The second mode of variability is a low-amplitude fluctuation of weak periodicity that is weakly synchronised across the country. These observations support a hybrid cyclic–eruptive theory of outbreak occurrence that is not consistent with the simpler idea of spatially synchronised cycling.

Seven species of Polydrusus Germar weevils (Coleoptera: Curculionidae) occur in the United States of America and Canada, three of which are introduced from Europe, are polyphagous, and may be displacing native weevil fauna in select areas of North America. We review host plant information for these species and provide distributional maps for each. We also present results on the seasonal phenology and sex ratios of two nonnative species, Polydrusus impressifrons (Gyllenhal) and Polydrusus formosus (Mayer), recorded in 2020 and 2021 in two orchards of hybrid hazelnuts (Betulaceae) in Minnesota, United States of America. These two species may present an episodic threat to the burgeoning hybrid hazelnut industry due to their ability to damage buds, foliage, and roots of hardwoods. We found that adults of these two species began emerging in late May of each year and remained present until mid-July. We found higher numbers of P. formosus than of P. impressifrons on hazel plants. Sex ratios of both species were generally between 50–60% male. We supply a compendium of species descriptions that (1) distinguishes between native and nonnative species and (2) identifies the sex of nonnative species. This research contributes to work on the ecology of Polydrusus, conservation of native species, and the management of tree crops.

The longhorn beetle, Cerambyx welensii (Küster) (Coleoptera: Cerambycidae), is considered a critical factor in oak decline in southwestern Iberia, but populations vary over space and time, depending on several ecological factors. Adults feed on ripe fruits and tree exudates, and evidence suggests that feeding could impact fitness in hot, dry summers, especially under climate change. In the present study, we assessed the impact of adult feeding (sugar-fed, water-fed, or unfed) and remating (monandrous versus polyandrous) on female reproductive output. Lifetime fecundity increased with female size in most feeding–remating combinations. Sugar-fed females achieved the highest longevity and fecundity, unfed females the lowest, and water-fed females had intermediate values. The daily fecundity pattern was strongly dependent on female feeding. Longevity and fecundity of once-mated and remated females were similar in both unfed and water-fed groups; however, in sugar-fed females, remating enhanced fecundity and shortened life span. Preoviposition, oviposition, and postoviposition periods were distinctly affected by both diet and remating. Results show that females require sugar to maximise reproductive output and that a water supply may partially mitigate the fitness decline of unfed females. We conclude that female feeding must be considered to explain C. welensii spatio-temporal occupancy–abundance patterns in oak woodlands.

Mantids are influential generalist predators in terrestrial systems. Therefore, large mantid species like the European mantid, Mantis religiosa (Linnaeus, 1758), are often used by humans and purposefully introduced as a form of biocontrol, greatly expanding their geographic ranges. However, mantids are rarely recorded in marine systems. In this study, we present an observation of European mantids living in a salt marsh and actively moulting in the vegetation in Elkhorn Slough, in Monterey Bay, California, United States of America. Not only are these European mantids a nonnative species, but every observed individual was a flightless juvenile, meaning they hatched nearby. Although mantids are not usually associated with intertidal ecosystems, there are multiple potential reasons that mantids would be drawn to salt marshes, including food, potential for camouflage, and lower predation pressure. The addition of a generalist predator could produce a complex mix of positive and negative impacts on the marsh itself and, given the importance of marsh systems, these possible effects warrant further study.

As urbanisation continues to increase, terrestrial arthropod diversity declines. Urban green spaces represent unique opportunities to preserve arthropod diversity in urban environments. We quantify how ground-dwelling arthropod communities vary both seasonally and across three differently maintained stormwater infiltration basins in Ellisville, Missouri, United States of America. One basin was routinely mowed, a second was mowed only seasonally, and a third was intentionally planted to attract pollinators and was not mowed during this study. We expected higher plant diversity to correlate with higher arthropod diversity. Therefore, we expected the unmowed basin to have the highest levels of arthropod diversity and abundance and the mowed basin to have the lowest. Four collection periods spanned spring, early summer, late summer, and fall. During each collection period, five pitfall traps were placed throughout each basin for 48 hours. In total, 5686 specimens were collected and identified, representing 59 families. Arthropod communities did not vary across basins or collection dates, largely contrasting with existing literature. The results of this study do not indicate that different mowing regiments in infiltration basins will affect the ground-dwelling arthropod communities at a family level, although the effect on species-level diversity remains to be investigated.

A new species of frog-biting midge in the genus Corethrella Coquillett from Death Valley National Park, California, United States of America, is described, based on a single female. The species belongs to the rotunda species group, which are otherwise known to have hyporheic larvae. The species is placed phylogenetically within the group, and a modified portion of a Nearctic key is presented. The rotunda species group now contains 13 species, three of which are in the Nearctic, and the remaining 10 of which are in the Neotropical region.

The invasive pea leaf weevil, Sitona lineatus (Linnaeus) (Coleoptera: Curculionidae), damages field peas, Pisum sativum Linnaeus (Fabaceae), and faba beans, Vicia faba Linnaeus (Fabaceae), on the Canadian prairies. We used semiochemical-baited pitfall traps to monitor and detect S. lineatus range expansion and capture associated predaceous ground beetles (Coleoptera: Carabidae) in pulse-growing regions across Alberta. Traps captured male and female S. lineatus in all pulse-growing regions in the spring and fall, including a first record of S. lineatus in the Peace River region of northwestern Alberta. Pheromone-baited traps captured more weevils than unbaited traps did, and the addition of host plant volatiles did not increase the catch. More weevils were captured in traps in pea fields compared to in faba bean fields. Rubber septa lures released more pheromones and attracted a similar number or more weevils to traps than microcentrifuge tube lures did. Ground beetle capture was not affected by semiochemical baits targeting S. lineatus. Ground beetle diversity varied by region and collection period, but the most frequently collected species was Pterostichus melanarius, a potential predator of S. lineatus. This study shows that pitfall traps baited with rubber septa pheromone lures can be used to monitor new and expanding S. lineatus populations, as well as potential natural enemy communities.

We report the presence of three Palaearctic species, Suillia variegata (Loew), Tephrochlamys flavipes (Zetterstedt), and Tephrochlamys tarsalis (Zetterstedt) (Diptera: Heleomyzidae), recently introduced to North America. We use community science (also known as citizen science) data to show that S. variegata, which was first reported in Portland, Oregon, United States of America, in 2016, has persisted in that area and has subsequently also been observed in Washington and California. Tephrochlamys flavipes, first reported in Seattle, Washington, United States of America, in 2010, has been observed comparatively more rarely, in a more restricted geographic area. The presence of T. tarsalis in the Nearctic, previously reported in Canada based on genetic barcodes, is verified from photographs taken in British Columbia, Canada and Washington. We provide updates to the keys to Suillia Robineau-Desvoidy and Tephrochlamys Loew of the United States of America and Canada. Finally, we discuss potential means of introduction and patterns of dispersal for each species.

Freshwater biodiversity is increasingly at risk wherever land uses such as agriculture exert multiple stressors that degrade habitat quality. Although stream macroinvertebrates act as bioindicators for monitoring these impacts, their responses are context-specific: examining drivers of community composition is therefore important to understand the results of monitoring efforts. In a primarily agricultural landscape, 15 sites across the Sydenham River watershed, Ontario, Canada, were assessed for in-stream habitat quality and stream macroinvertebrate diversity. We predicted that community assemblage would be driven by differences in surficial geology across branch (east branch versus north branch) and catchment position (main stem versus tributary). We found that the main stem of the east branch was characterised by significantly higher proportions (P = 0.053) and abundance (P = 0.038) of Ephemeroptera–Plecoptera–Trichoptera (EPT) taxa than north branch sites were, and sites in the east and north branch tributaries were characterised by significantly lower Hilsenhoff Biotic Index (HBI) scores (P = 0.088). Redundancy analysis found that substrate size was the main driver of community composition, generating a model that described these patterns across branch and catchment position. Our findings suggest that EPT abundance and HBI scores were the variables that were most effective at revealing differences in stream communities due to agricultural impacts and that sediment size is an important driver of these patterns.

In 2014, Amblyseius andersoni (Acari: Phytoseiidae), was newly discovered in apple (Rosacaea) orchards in central Japan. In 2022, I found A. andersoni on leaves in an apple orchard in northern Japan. Amblyseius andersoni had been not observed in the orchard until at least 2018; only Neoseiulus womersleyi and Typhlodromus vulgaris (Mesostigmata: Phytoseiidae), both of which are native to Japan, had been observed on apple leaves. To understand the impact of A. andersoni on the two phytoseiid mite species, I compared the seasonal occurrences of the phytoseiid species and of Tetranychus urticae (Trombidiformes: Tetranychidae) in the orchard in 2018 and 2022. In both years, T. urticae numbers increased from mid-July to early August and then rapidly decreased with increasing N. womersleyi numbers. Mean total occurrence numbers of N. womersleyi and of T. urticae did not differ significantly between the two years. Amblyseius andersoni occurrence therefore likely had little impact on seasonal N. womersleyi occurrence. In contrast, in 2018, many T. vulgaris individuals were observed from August onwards, when T. urticae numbers had decreased, but T. vulgaris was seldom observed in 2022, although many A. andersoni were, suggesting that A. andersoni likely displaced T. vulgaris in the apple orchard.

To reconstruct behavioural changes that underpin evolutionary transitions between solitary and eusocial behaviour, we need detailed behavioural information about both solitary and eusocial species. Most behavioural studies of sweat bees have focused on sociality. We addressed the lack of detailed information about solitary species using pinned specimens of Lasioglossum leucozonium (Schrank) and L. zonulum (Smith) from Ontario (2003–2019) and Alberta (2016). We used weekly abundance of trapped bees to evaluate flight phenology (univoltine versus bivoltine), delineating two phases of flight activity, P1 and P2, before and after the first appearance of males, and evaluated female traits related to reproduction (body size, wear, and ovary development). All populations were confirmed to be solitary. The Ontario L. leucozonium and Alberta L. zonulum were univoltine, with P1 and P2 females being similar in size but P2 females more worn and with less-developed ovaries. Ontario L. zonulum were bivoltine, with P2 females being larger, more worn, and having more ovary development than P1 females, a unique pattern among bivoltine sweat bees. Contrasting observations between univoltine and bivoltine populations support the contention that solitary reproduction is not necessarily “simple” and that detailed information is needed to illuminate behavioural changes during bee social evolution.

Alpine tundra areas are threatened by anthropogenic climate change. They are also often represented as hotspots of endemism. Studying the insect communities associated with these habitats is therefore highly relevant. Melanoplus gaspesiensis Vickery is a grasshopper species known for its extremely limited distribution; it is considered endemic to Mont Albert, on the Gaspé Peninsula, Québec, Canada. Given its extremely limited distribution and with its habitat being particularly sensitive to climate change, the species is likely to soon be considered “at risk” at both the provincial and national levels. In order to confirm the current distribution of M. gaspesiensis, we sampled Acrididae on four alpine summits of the Gaspé Peninsula. Four species of Acrididae were captured. Almost 85% of the captured specimens were M. gaspesiensis, all of which were captured on Mont Albert. Our data are thus coherent with the species being endemic to that summit. The unique geology of Mont Albert (serpentine) may explain why M. gaspesiensis appears to be restricted to this one summit.