Three new species of Ypresian (early Eocene) Odonata are described: Paradysagrion sosbyae gen. and sp. nov. from the Klondike Mountain Formation at Republic, Washington, United States of America, and Dysagrionites allenbyensis sp. nov. and Allenby gen. and sp. A from the Allenby Formation near Princeton, British Columbia, Canada. All three are assigned to the Dysagrionidae and Cephalozygoptera but only tentatively, as key diagnostic morphology is missing from their incomplete fossils. The definition of the collective genus Dysagrionites is broadened to include odonates tentatively assigned to the Dysagrioninae (Dysagrionidae) that are distinct as species but have unclear nominal genus affinity.

The phoretic mite assemblage of the Douglas-fir beetle, Dendroctonus pseudotsugae Hopkins (Coleoptera: Curculionidae), has not been thoroughly documented. Phoretic mites can impact fitness and population dynamics of hosts; documenting a mite assemblage may provide information on their ecological roles. We caught Douglas-fir beetles in central British Columbia, Canada, and sorted associated mites into morphospecies. Representatives of the morphospecies were DNA barcoded (CO1 barcode region), indicating at least nine operational taxonomic units (OTUs). Representatives of all OTUs were slide-mounted and morphologically identified. There was a mean of 50.5 ± 4.7 mites per beetle, with both females and males carrying similar numbers of most mite species, except for OTU B1, which was found in higher numbers on females. OTU B1, Parawinterschmidtia furnissi (Woodring) (Astigmata: Winterschmidtiidae), was found in substantially higher numbers than all other OTUs and was always clustered in large aggregations in an anterior pocket on the beetles’ subelytral surface. When this OTU was removed from the calculation, the mean number dropped to 1.3 ± 0.2 mites per beetle. The consistent high numbers of OTU B1 in conjunction with its consistent anatomical aggregation suggests an important interaction between this particular mite species and the Douglas-fir beetle.

It is unclear whether larval infestations of Rhagoletis pomonella (Walsh) (Diptera: Tephritidae) in earlier (softer) apple (Rosaceae) cultivars are greater than in later (firmer) apple cultivars in Washington State, United States of America, where flies were introduced and are quarantine pests of apple. Here, a field survey of apples in a noncommercial setting in Washington and experiments testing whether earlier apples are more suitable than later apples for Washington-origin R. pomonella were conducted. Early season ‘Gala’ and ‘Golden Delicious’, midseason ‘Red Delicious’, and late-season ‘Granny Smith’ and ‘Fuji’ were exposed to flies reared from early and midseason apples in laboratory experiments and to wild flies in apple trees in field experiments. The field survey provided evidence for softer apples being more infested and suitable. Likewise, most of the laboratory and field experimental data showed that ‘Gala’ and ‘Golden Delicious’, two of the softer apples tested, produced the most larvae and were most suitable, regardless of whether test apples were conventional or organic and ripe or unripe. To optimise fly trapping protocols in Washington, trapping in early apple trees near ‘Gala’ and ‘Golden Delicious’ orchards should be prioritised over trapping near mid- or late-season apple cultivar orchards.

The taxonomy of the subfamily Scolytinae has traditionally been based on external morphological attributes corresponding to the elytral declivity, head, and pronotum. Some traits from the general morphology of the aedeagus and spermatheca have been proposed in scarce genera. In this study, we explore and improve a technique of endophallus inflation to apply it in Scolytinae members and to describe its morphology for the first time in 16 species from Dendroctonus Erichson, Ips DeGeer, and Phloeosinus Chapuis. These taxa display differences in the attachment types of endophallus and two distinct inflation and retraction mechanisms. Our results support the use of the internal sac as a taxonomic feature in Scolytinae because each tribe, genus, and species display a particular morphological pattern. The results also indicate use of the internal sac for Dendroctonus taxonomy supports phylogenetic inferences.

Starting in the 1960s, the flea beetle Longitarsus jacobaeae (Waterhouse) (Coleoptera: Chrysomelidae) has been imported and relocated to North America for the control of the weed tansy ragwort, Jacobaea vulgaris (Asteraceae). Some Longitarsus species are morphologically almost indistinguishable, leading to questions regarding the taxonomic identity of the beetles released. Here, we present the results of a molecular study that addresses these questions and updates a list of the releases of Longitarsus within Canada. Our findings confirm the suspected release of the cryptic species L. flavicornis concurrent with releases of L. jacobaeae at sites in British Columbia, Canada, in the 1970s. However, we find no evidence for the continued presence of L. flavicornis at historical release sites in British Columbia nor in Nova Scotia, Canada, where it might potentially have been redistributed. We confirm the presence of L. gracilis Kutschera in Nova Scotia and British Columbia, the latter population likely established from a 2005 release of Longitarsus from Nova Scotia. To our knowledge, this study provides the first published confirmation of L. gracilis in Canada. Finally, we provide evidence that what were recognised in earlier work as three separate taxa (L. succineus (Foudras), L. near noricus, and Longitarsus sp.) are likely all L. succineus.

Sand flies are potential carriers of various diseases that are transmittable to humans and animals. In this study, United States Centers for Disease Control light traps were set up in four tourist caves in the Thai provinces of Surat Thani, Nakhon Si Thammarat, Satun, and Chumphon to capture Idiophlebotomus asperulus sand flies. Over a period of three months, April to June, in 2017, a total of 181 female Idiophlebotomus asperulus sand flies were captured during nightly operations. The sand flies were dissected into 23 external and internal parts to identify their morphological characteristics. Statistical analysis was then conducted on these morphological characteristics, involving both univariate analysis (one-way analysis of variance and the Kruskal–Wallis test) and multivariate analysis (canonical discriminant analysis). Levene’s, the Kolmogorov–Smirnov, and Box’s M tests were used for the preliminary statistical screening of the data. The test results revealed significant morphological differences in the sand flies from the four provinces with regard to their antenna segments 5, palpal segments 3, pharynxes, hindlegs, femurs, and spermathecae. These morphological differences in the southern Thai Idiophlebotomus asperulus sand fly population suggest the possibility that at least three morphologically different populations are found in this region.

Northern British Columbia, Canada, is an undersurveyed region for aquatic macroinvertebrates. We surveyed the Stellako River, a culturally and economically important river in the region, for adult caddisflies using Malaise traps, then identified species by using DNA barcoding, which revealed the presence of Protoptila coloma Ross (Trichoptera: Glossosomatidae). This is the first record of this species in Canada; it represents a 680-km northwards expansion of the species’ currently known range.

Little is known about the distribution and natural history of hoverflies (Diptera: Syrphidae) in western Canada. Filling in knowledge gaps and tracking this potentially changing fauna are important because hoverflies are likely important pollinators and are natural pest control agents for crops. Hoverflies were collected using Malaise traps placed near fields seeded to canola in central Alberta from May to August 2021. Platycheirus varipes Curran represents a new species record for Alberta. Two species of conservation concern and two species with extremely limited collection records were also collected. A species that was previously found only in mountainous regions and another three species whose Albertan records consisted only of iNaturalist records were found.

In many regions of Canada, knowledge of the distribution of insect species is far from complete. This knowledge gap, known as the Wallacean Shortfall, is often manifest by species records separated by large, often remote areas with no records. Paradoxically, these difficult-to-access areas offer the best opportunity to study unaltered native community assemblages. Such gaps in knowledge are exemplified by ground beetles, a well-known group, yet with record gaps in many unstudied areas of Canada, including Akimiski Island, Nunavut. This postglacial rebound island, located in James Bay, has no permanently occupied human dwellings and almost no human-altered habitat. Using a combination of pitfall-malaise traps, pitfall traps, and hand captures during 2008–2014, we collected 1368 ground beetles (Coleoptera: Carabidae) as part of a larger biodiversity survey. We identified 31 species, 29 of which were first territorial records for Nunavut. Our results almost double the number of Carabidae known from Nunavut and extend the known range of eight other species. Seventeen of the species that we caught cannot fly, evidence for colonists arriving on Akimiski on floating debris. Our study fills substantial range gaps and serves as baseline information to detect future change.

Management of phytosanitary and biosecurity risks associated with the Cerambycidae focuses on prevention and early detection. Semiochemical-baited traps are an important component of these management efforts. Cerambycid pheromones are often screened in field trials to develop inventories of which species can be surveyed with which semiochemicals. We report field trials of two types of intercept traps (four- and three-sided panel traps) baited with known Cerambycidae pheromones aimed to capture Peruvian fauna. Intercept traps were baited with anti-2,3-hexanediol, fuscumol, and fuscumol acetate alone and in binary and ternary blends. The most frequently captured species was Megacyllene andesiana (Casey) (Coleoptera: Cerambycidae) (n = 268), followed by Oreodera bituberculata Bates (Coleoptera: Cerambycidae) (n = 59), Discopus eques Bates (Coleoptera: Cerambycidae) (n = 37), and Aegomorphus longitarsis (Bates) (Coleoptera: Cerambycidae) (n = 31). Trap type did not affect capture rates. Male and female M. andesiana were attracted by anti-2,3-hexanediol. The addition of fuscumol, fuscumol acetate, or the combination of fuscumol and fuscumol acetate reduced male M. andesiana captures, whereas the addition of fuscumol and the combination of fuscumol and fuscumol acetate reduced the response of female M. andesiana. Male O. bituberculata were attracted to traps baited with fuscumol, and this response was reduced by the addition of fuscumol acetate, whether or not anti-2,3-hexanediol was present.

We test whether tissue moisture content affects settling and feeding behaviours of Monochamus galloprovincialis, a forest insect that feeds on multiple pine species and is a vector of tree disease. In a watering experiment using potted Aleppo pine trees, Pinus halepensis Miller (Pinaceae), water deprivation reduced mid-day shoot water potentials and corresponded to lower phloem water content. In short-term choice assays allowing prereproductive beetles to select among P. halepensis phloem for maturation feeding, beetles preferred to settle and initiate feeding on phloem with lower moisture content and over a 24-hour period consumed more phloem from oven-dried phloem punches. No differences in settling and feeding preferences between males and females were observed. In no-choice feeding assays where beetles were confined to either “dry” or “fresh” shoots (moisture differential ∼10%) over a five-day period, beetles fed on fresh shoots excreted on average 38% more frass, potentially consistent with higher consumption requirements. Our data suggest that water input affects shoot water potentials of Aleppo pine and corresponding phloem water content, which influences feeding preferences of newly emerged M. galloprovincialis.

Studies documenting insect succession throughout the decomposition of vertebrate remains have been performed in more than half of the provinces and one territory in Canada. However, some areas are not represented in the current published literature. Ontario is one province that does not have published records of local necrophagous insect succession. Therefore, three studies were performed in Oshawa, Ontario, to document the insect community and primary colonisers observed during the decomposition of domestic pig, Sus scrofa domestica (Artiodactyla: Suidae), remains. Adult and immature specimens located on the remains were collected, reared, and identified. Pitfall traps were installed to monitor insects present outside of visits. Pigs that decomposed in higher temperatures yielded fewer colonising dipteran species than those that decomposed in cooler temperatures. The most common primary colonisers were Phormia regina (Diptera: Calliphoridae), Lucilia illustris (Diptera: Calliphoridae), and Lucilia sericata (Diptera: Calliphoridae). In total, 11 Diptera families, six Coleoptera families, and families from the Hymenoptera and Hemiptera orders were observed. When comparing these results to published results from Québec, Ontario’s neighbour, major differences in primary colonisers can be noted. It is therefore important for researchers to study the succession, development, and colonisation patterns of the local fauna during vertebrate decomposition and to publish their findings.

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.

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.

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.

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.

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.

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.

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.

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.