The field of Quaternary entomology has focused primarily on the study of beetles (Coleoptera) and, to a lesser degree, nonbiting midges (Diptera: Chironomidae). Beetles typically predominate because they have heavily sclerotised exoskeletons, and they are abundant in a great variety of habitats. Because of taphonomy and scarcity, other Quaternary invertebrates have been less studied. Only a few records of fleas (Siphonaptera) and mites (Acari) are reported from Pleistocene deposits that span the Seward Peninsula in Alaska, United States of America, to the Klondike goldfields in central Yukon Territory, Canada. Grasshoppers (Orthoptera) and thrips (Thysanoptera) have not been reported previously from Quaternary deposits across the Arctic’s Beringia region. However, recent extensive sampling of Arctic ground squirrel, Urocitellus parryii Richardson (Rodentia: Sciuridae), middens from permafrost deposits of the Klondike goldfields has yielded specimens from each of these underrepresented invertebrate groups. Here, we present records of fleas (Oropsylla alaskensis Baker (Ceratophyllidae)), mites (including Fusacarus Michael (Astigmata: Glycyphagidae) and cf. Haemogamasus Berlese (Mesostigmata: Laelapidae)), and the first records of grasshoppers (Acrididae: Gomphocerinae) and thrips (Thysanoptera: Thripidae) from Beringia from six middens spanning approximately 80 000–13 500 years BP. We also provide brief reviews of the fossil history of each major taxon.

Nonnative earthworm species are invading the boreal forest in North America. Oribatid mites are key detritivores in boreal forest soils, initiating litter decomposition and maintaining forest floor structure. Earthworms are also detritivores and are considered ecosystem engineers. When introduced into nonendemic environments, earthworms may alter soil biogeochemical cycling and adversely affect oribatid mite communities. However, to our knowledge, no field studies in boreal forests have investigated invasive earthworms and their impacts on oribatid mites. The present study was conducted in a boreal trembling aspen, Populus tremuloides Michaux (Salicaceae), stand near Wolf Lake, Alberta, Canada. After assessing the current state of earthworm invasion, we identified an area with a lower density of earthworms that was invaded by one species, Dendrobaena octaedra Savigny (Crassiclitellata: Lumbricidae), and an area with a higher density of earthworms that was invaded by multiple species, D. octaedra (Crassiclitellata: Lumbricidae) and Aporrectodea spp. (Crassiclitellata: Lumbricidae). The higher-density area was associated with lower understorey vegetation species richness and with thinner forest floors characterised by higher bulk density but lower total organic carbon and nitrogen stocks. Oribatid mite community composition differed between the two areas, and their richness significantly decreased with higher earthworm density. Our findings suggest that earthworm invasion is substantially disrupting habitat for oribatid mites and might affect the overall boreal ecosystem equilibrium in the long term.

Metarhizium guizhouense (Clavicipitaceae) is an insect pathogen employed as a mycoinsecticide against many insect pests worldwide. In this study, for the first time in a laboratory setting, the pathogenicity of the M. guizhouense isolate PSUM04 was evaluated against the coffee berry borer, Hypothenemus hampei (Coleoptera: Curculionidae: Scolytinae). Following the exposure (1 × 109 spores/mL) of H. hampei to M. guizhouense PSUM04, morpho-histopathological changes and numbers of apoptotic cells via the TUNEL (terminal deoxynucleotidyl transferase (TdT), dUTP (deoxyuridine triphosphate) nick-end labelling) assay in H. hampei were evaluated at 12-hour intervals until 144 hours after exposure. The external morphology of H. hampei underwent drastic changes from 24 to 144 hours post-exposure accompanied by the degeneration of integument and adipose tissues. The semi-quantitative analytical score of TUNEL-positive cells showed a slight increase at 12 hours after exposure and a significant increase in TUNEL-positive apoptotic cells at 48 hours after exposure. These results suggest a series of tissue alterations of H. hampei during its process of infection with a strain of M. guizhouense, highlighting the pathogen’s potential as a biological control agent in natural settings.

The Noctuidae (Lepidoptera) comprise the most diverse and abundant lepidopteran families in the Canadian Prairie Ecozone. Within this group, some species are agricultural pests that require monitoring. Pheromone lures target specific species, whereas food-bait lures attract a broader range. This study reports the diversity and abundance of noctuid moths captured in traps baited with female sex pheromones of pest species and with food-bait lures consisting of acetic acid and 3-methyl-1-butanol (AAMB) with fermented byproduct or floral volatile compounds. Food-bait lures that attract pests and nonpest species can provide insight into moth populations and species richness in human-managed ecosystems. We trapped moths in wheat (Poaceae) and canola (Brassicaceae) fields in central Alberta, Canada. We captured and identified to species approximately 7900 noctuid moths. Community composition was similar in both crops. Sex pheromone–baited traps had variable specificity and low nontarget diversity. Traps baited with AAMB captured greater moth diversity than unbaited traps did. Noctuinae were the most diverse and abundant in AAMB-baited traps (62 species across 8 tribes). The AAMB lures captured more cutworm and armyworm pests than unbaited traps did. Fermented byproduct food–bait lures captured more noctuid pests than floral volatiles did. The AAMB lures can be implemented to monitor Noctuinae diversity and potentially assess local noctuid pest density in agroecosystems on the Canadian prairies.

Four Palaearctic species of Staphylininae (Coleoptera: Staphylinidae) are reported from North America for the first time: Heterothops cognatus Sharp, H. praevius (Erichson), Philonthus chujoi Dvořák, and Quedius (Raphirus) maurorufus (Gravenhorst). We suspect that these species are part of a more recent cohort of accidental introductions to North America. Notably, two of them are native to the East Palaearctic, an unusual source of adventive staphylinids in North America because nearly all others are native to Central Europe. We suggest that the East Palaearctic is an underrecognised and increasingly important source for recently adventive soil invertebrates and that increased taxonomic focus on this fauna is important to North American biosecurity. The detection of trans-Palaearctic H. praevius resulted in the recognition of H. praevius Erichson (= H. marmotae Smetana syn. nov.). We also newly report the Nearctic species Heterothops conformis Smetana and H. sordidus Smetana from eastern North America. Philonthus debilis, a close relative of P. chujoi, is reported from the Yukon Territory, representing the northernmost locality known for this long-established adventive species. Illustrations of diagnostic features, barcode data, and distribution maps are provided for all four species. Updated or new identification keys are provided to aid in the recognition of these species in eastern North America.

Phytophagous insects are influenced by various abiotic factors, with temperature being a key determinant. We hypothesised that fluctuating thermal conditions would enhance antioxidant enzyme activity and nutrient assimilation in these insects. We investigated superoxide dismutase, catalase, and lipid peroxidation activity, as well as glucose and triglyceride assimilation in Parthenium beetles, Zygogramma bicolorata Pallister (Coleoptera: Chrysomelidae), under repeated exposure to short-duration heat (42 ± 2 °C) and cold (10 ± 2 °C), and optimal (27 ± 2 °C) temperatures, along with post-stress recovery. Results revealed that superoxide dismutase, catalase, and lipid peroxidation activity were highest under the heat stress and lowest under the cold stress conditions. Upon returning to optimal conditions, adults previously exposed to thermal stress showed reduced superoxide dismutase and catalase activity and elevated lipid peroxidation product levels compared to those reared continuously at optimal temperatures. Glucose assimilation was highest under cold stress, whereas triglyceride assimilation peaked under optimal temperatures. After stress conditions ended, glucose assimilation decreased in beetles across all temperature groups, whereas triglyceride assimilation increased in adults that had been maintained at optimal temperatures. Adult mortality peaked under heat stress, with male beetles showing higher mortality rates than females did. Moreover, male beetles exhibited higher enzyme activity, whereas female beetles assimilated more glucose and triglycerides, suggesting greater thermal-stress tolerance in the females. These findings imply that female Parthenium beetles are more resilient to thermal stress and are therefore more effective for use in Parthenium (Asteraceae) biocontrol.

Climate change and other anthropogenic stressors are reshaping Earth’s biodiversity, motivating efforts to monitor changing faunal diversity. Canada is home to 80 documented species of mosquitoes, 38 of which are reported in New Brunswick. Using Centers for Disease Control and Prevention miniature CO2 light traps, three adult mosquito collection surveys were performed to encompass 43 trapping sites across New Brunswick, Canada. Study one took place from 21 July 2022 to 9 September 2022, study two took place from 29 May 2023 to 24 October 2023, and study three took place from 15 May 2024 to 19 September 2024. Among the specimens collected, a total of 18 Uranotaenia sapphirina (Osten Sacken) (Diptera: Culicidae) were identified from five separate trapping sites. This species, previously documented only in Ontario, Quebec, and Manitoba, is considered rare in Canada and is known for its specialisation in feeding on annelids rather than vertebrates. Our detection of Ur. sapphirina in New Brunswick, where it has been absent in earlier surveys, suggests a recent range expansion, possibly driven by climate change. This observation highlights the need for ongoing surveillance to monitor the impacts of environmental changes on mosquito distribution.

The fly Heleomyza serrata (Linnaeus) (Diptera: Heleomyzidae) is reported to range widely throughout the United States of America and Canada. However, in Eurasia, this species is restricted to northern regions; in central and southern Europe, H. serrata is replaced by the similar species H. captiosa (Gorodkov), which can be distinguished from H. serrata by the male genitalia. We report H. captiosa from Kentucky, United States of America, the first Nearctic record of this species. The taxonomy of Nearctic Heleomyza Fallén is discussed, and we propose to transfer three species to the genus Scoliocentra Loew: Scoliocentra (Scoliocentra) bisetata (Garrett) comb. nov., S. (Leriola Gorodkov) latens (Aldrich) comb. nov., and S. (L.) nebulosa (Coquillett) comb. nov. We recognise Anypotacta Czerny as a subgenus of Heleomyza and transfer the two Nearctic species to that genus: H. (A.) aldrichi Garrett comb. nov. and H. (A.) gilli nom. nov. (new replacement name for Anypotacta czernyi Gill, 1962). Finally, we provide an updated key to Nearctic Heleomyza and morphologically similar species of Scoliocentra. Further study will be required to ascertain the range and abundance of H. captiosa in North America.

Spiders (Araneae) are an abundant and diverse arthropod group that serve important ecosystem functions in boreal forests. Several hundred species across boreal Canada are prey for vertebrates and invertebrates. Spiders are also generalist predators that likely contribute to pest control. Our understanding of spider assemblages, particularly of the arboreal community, is minimal at the stand level in many habitats across Canada. Habitat-specific factors like connectivity, microclimate, and neighbour effects can substantially influence the structure of ecological communities. Well-replicated landscape-scale experimental designs enable us to better understand the structure of arboreal spider communities. Here, we employed beat-sheeting to characterise spider assemblages on balsam fir trees (Pinaceae) from the three most common stand types found in the boreal: coniferous, deciduous, and mixedwood. Fir trees in deciduous stands had greater spider abundance than did the trees in coniferous or mixedwood stands. Neither species diversity nor composition differed significantly among the three stand types. Our results suggest that spiders likely do not recognise “the forest for the trees.”

Bacteria play a fundamental but often overlooked role in shaping insect communities in cattle (Bovidae) dung. To direct attention to this role, three experiments were performed with cattle dung autoclaved to reduce bacterial activity and the associated release of volatile organic compounds (VOCs) that attract coprophilous insects to deposits. In the first experiment, and consistent with expectations, fewer insects were recovered in pitfall traps baited with autoclaved versus control dung. In the second experiment, there was generally lower recovery of insects developing in autoclaved versus control pats colonised in the field. This result was attributed to reduced oviposition and lower survival of immature insects in the autoclaved pats. In the third experiment, no effect of autoclaved versus control dung was detected on the reproductive success of the dung beetle Onthophagus taurus (Linnaeus) (Coleoptera: Scarabaeidae), possibly because adults carry with them the requisite bacteria for larval development. In summary, faecal bacteria produce VOCs to directly affect the composition of the insect species that colonise and oviposit in cattle dung. The survival of their progeny is affected by faecal bacteria that provide a source of nutrients or may be pathogenic.