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.