The elm zigzag sawfly, Aproceros leucopoda Takeuchi (Hymenoptera: Argidae), was reported for the first time in North America during the summer of 2020. Characteristic zigzag defoliation was reported in the province of Québec, Canada, on the community science website, iNaturalist. Field trips conducted to the site resulted in the collection of live specimens (a few larvae and a cocoon from which an adult emerged) and onsite observation of diagnostic defoliation and empty cocoons, confirming the presence of this exotic species in Canada. Subsequent inspection of elm trees by naturalists and scientists in the south of the province led to the conclusion that the species is more widely distributed than first expected and that the invasion is not localised to a small area. Preliminary genetic data pointed to a possible European origin of the Canadian population, but conclusive assignment to source will require examination of more specimens and the collection of reference sequences from different European and Asian populations. This is a good example of the importance of community science in the detection of new invasive species.

In stag beetle larvae, food availability is considered a major cause of body size variation in adults, but this has not been explicitly tested. To evaluate wood use and the effects of food quantity on growth and adult body size, the feeding performance of the tropical stag beetle Aegus chelifer MacLeay (Coleoptera: Lucanidae), which is widely distributed in Southeast Asia, was investigated by rearing larvae with different food quantities. Apparent digestibility was approximately 9%, and the efficiency of conversion of ingested food ranged from 0.7% to 1.7%. Feeding period, total food consumption, and adult body size significantly increased alongside food quantity. Males had higher consumption rates than females did at the same larval weight due to shorter food retention time. Males showed greater variation in feeding, growth performance, and adult body size than females. Differences in feeding performance that depend on food availability may enhance their fitness and may further result in sexual differences and adult body size variation.

A revised key to the 94 species of Lasioglossum (Dialictus) currently known to occur in Canada is presented, incorporating new species and taxonomic updates since the publication of the first key in 2010. Two new species, Lasioglossum (Dialictus) immigrans and Lasioglossum (Dialictus) onuferkoi, are described from Canada. Lasioglossum (D.) ascheri, L. (D.) stictaspis, and L. (D.) tegulariforme are reported or confirmed from Canada for the first time. Lasioglossum (D.) gaudiale (Sandhouse, 1924) and L. (D.) helianthi (Cockerell, 1916) are resurrected from synonymy with L. (D.) tegulariforme (Crawford, 1907). The following five new synonymies are established: L. (D.) stictaspis (Sandhouse, 1923) (= L. (D.) albuquerquense (Michener, 1937)); L. (D.) ascheri Gibbs, 2011 (= L. (D.) curculum Gibbs, 2011); L. (D.) helianthi (Cockerell, 1916) (= L. (D.) imbrex Gibbs, 2010); L. (D.) megastictum (Cockerell, 1937) (= L. (D.) punctiferellum (Cockerell, 1937)); and L. (D.) obnubilum (Sandhouse, 1924) (= L. (D.) lilliputense Gibbs, 2010). Previously undescribed males of L. (D.) helianthi, L. (D.) reasbeckae, L. (D.) tegulariforme, and L. (D.) weemsi are diagnosed and figured.

Knowledge about the ideal host ratio per female parasitoid reared in glass tubes is important for obtaining descendants with better biological quality. The study aimed to evaluate the reproduction of Ooencyrtus submetallicus (Hymenoptera: Encyrtidae) females in egg densities of Euschistus heros (Hemiptera: Pentatomidae) to find the most adequate relationship between parasitoids and hosts aiming at the parasitoid multiplication. The experiment was conducted with E. heros eggs at densities (parasitoid:host) of 1:3, 1:6, 1:9, 1:12, 1:15, or 1:18 with 24 hours of parasitism by O. submetallicus. The parasitoid females and the egg carton were placed in glass tubes and kept in a climate-controlled chamber. The percentage of parasitism was affected by the nonparasitised eggs. The emergence of adult parasitoids, number of parasitised eggs, number of individual parasitoids emerging per egg, the length of the parasitoids’ posterior tibiae, and the parasitoids’ longevity, life cycle, and sex ratio were not affected by the different densities of nonparasitised eggs subjected to treatments. Ooencyrtus submetallicus parasitised and developed in E. heros eggs in all evaluated densities, with 1:6 presenting the best combination of parasitoid and host.

Neorthacheta dissimilis Malloch (Diptera: Scathophagidae) is a poorly known scathophagid fly that feeds and develops on iris (Iridaceae). A survey of its occurrence was performed at the Montréal Botanical Garden (Montréal, Québec, Canada) in 2018, 2019, and 2020. Iris species and cultivars from two subgenera, Iris and Limniris, were evaluated for larval infestation. When pooled for subgenera and years, data from 18 Iris classes revealed high levels of infestation per flower stalk, ranging from 34% to 100%. When analysed per bud or flower, levels of infestation remained high, ranging from 19% to 100%, but generally was lower than for flower stalks as the unit of replication. The mean number of N. dissimilis larvae per infested flower or bud was higher for the subgenus Limniris (1.13) than for the subgenus Iris (1.03), with a maximum of four N. dissimilis larvae per flower being observed. These figures are worrying for horticulturalists because the insect is prevalent and causes either abortion or aesthetic damages to iris flowers.

Litter-dwelling arthropods play an important role in maintaining forest ecosystem function. This study was designed to understand seasonal variations and diversity of litter-dwelling adult beetles, one of the most diverse groups of arthropods. Sampling was conducted in mixed-wood forests of South Korea between March and December 2019, covering all seasons, including winter. We used a sifting method and a Berlese funnel to collect arthropods living in leaf litter and soil. We collected a total of 5820 invertebrates representing six orders, of which 1422 were beetles representing 24 families and minimum 141 species. Beetle species richness was highest in spring and lowest in summer based on rarefaction and extrapolation. However, beetle abundance was lowest in spring, but abundance was similar among the other seasons. Beetle assemblage composition was correlated significantly with soil surface and atmospheric temperature. The assemblage composition differed among seasons, except between spring and winter, which overlapped slightly. The combined sifting–Berlese funnel method showed great advantages for investigating the diversity of overwintering arthropods. Continued study of the relationship between arthropods and the leaf-litter environment is essential to understand this microecosystem and will increase the chance of discovering new beetle species.

We report for the first time in India one genus, Bathanthidium Mavromoustakis, and the following four species of the bee tribe Anthidiini (Hymenoptera: Megachilidae) based on material deposited at the Zoological Survey of India, Kolkata: Anthidium (Anthidium) florentinum (Fabricius), Anthidium (Proanthidium) qingtaoi Niu and Zhu, Anthidiellum (Pycnanthidium) carinatum (Wu), and Bathanthidium (Manthidium) binghami (Friese). Illustrations of each of these species are provided, together with the information about their distribution, floral association, and diagnostic features.

The centipede fauna of Canada is reviewed based on information available in the literature and on examination of some material, and provincial and territorial distributions are provided. About 53 species are known from Canada, representing four orders: Scutigeromorpha (1), Scolopendromorpha (5), Geophilomorpha (19), and Lithobiomorpha (28). British Columbia has the most recorded species (23), followed by Ontario (17) and Newfoundland and Labrador (12). Arctogeophilus glacialis (Attems) and Alaskobius adlatus Chamberlin are newly reported from Canada (Northwest Territories), Schendyla nemorensis (Koch) is newly reported from Ontario, and Lithobius forficatus (Linnaeus) is recorded for the first time from New Brunswick and Prince Edward Island. Arctogeophilus melanonotus (Wood) is removed from the list of Canadian species.

We describe an experimental protocol for measuring the response of spruce budworm postdiapause larval development to temperature. This protocol is specifically designed to include measurements of development near their upper and lower thermal thresholds. The application of this protocol to a laboratory colony allowed for the first experimental evidence that spruce budworm larval development occurs at temperatures as low as 5 °C and as high as 35 °C, and it provides data to fit stage-specific development models. Our protocol is also designed to minimise mortality near the thermal development thresholds, thus allowing for multigenerational studies. We observed developmental plasticity in larvae reared at constant temperatures, particularly the occurrence of up to 42% of some individuals requiring only five instars to complete development compared to the expected six instars. The occurrence exhibited no clear relation to temperature. Although this protocol is specifically designed for spruce budworm, it provides a template for the study of other species’ developmental responses to temperature.

Many caterpillars exhibit patterns of ultraviolet (UV) fluorescence, although its purpose is unclear. We used realistic plasticine models of a fluorescing caterpillar species, the Polyphemus moth, Antheraea polyphemus (Lepidoptera; Saturniidae), adorned with fluorescent paint treatments and unpainted controls to quantify bird predation in two hardwood forested regions of New York State, United States of America. In separate field studies, significantly more birds struck deployed model caterpillars that had no UV fluorescence. More strikes on unpainted and clear paint treatments suggest paint itself did not impact predation, whereas similar predation attempts on bird and human-visible fluorescent dummies suggest that UV fluorescence and not UV reflectance was responsible for the observed effect. A second study found the dummy’s location on the tree was also important, but the low number of bird strikes limited analyses. Although our results do not identify a mechanism, fluorescence may function to deter or avoid predation. Our study contributes to a growing body of work investigating the importance of UV patterns in arthropods and highlights a potentially fruitful area of future research on predator–prey relations.

In the present study, we assessed functional response curves of two generalist coccinellid beetles (Coleoptera: Coccinellidae), specifically Menochilus sexmaculatus and Propylea dissecta, using fluctuating densities of aphid prey as a stimulus. In what may be the first such study, we investigated how the prey density experienced during the early larval development of these two predatory beetle species shaped the functional response curves of the late instar–larval and adult stages. The predators were switched from their rearing prey-density environments of scarce, optimal, or abundant prey to five testing density environments of extremely scarce, scarce, suboptimal, optimal, or abundant prey. The individuals of M. sexmaculatus that were reared on either scarce- and optimal- or abundant-prey densities exhibited type II functional response curves as both larvae and adults. However, individuals of P. dissecta that were reared on scarce- and abundant-prey densities displayed modified type II functional response curves as larvae and type II functional response curves as adults. In contrast, individuals of P. dissecta reared on the optimal-prey density displayed type II functional response curves as larvae and modified type II functional response curves as adults. The fourth-instar larvae and adult females of M. sexmaculatus and P. dissecta also exhibited highest prey consumption (T/Th) and shortest prey-handling time (Th) on the scarce-prey rearing density. Thus, under fluctuating-prey conditions, M. sexmaculatus is a better biological control agent of aphids than P. dissecta is.

Diamondback moth, Plutella xylostella (Linnaeus) (Lepidoptera: Plutellidae), a globally important pest of Brassicaceae crops, migrates into all provinces of Canada annually. Life tables were used to determine the mortality levels contributed by the parasitoid complexes associated with diamondback moth in British Columbia, Ontario, Prince Edward Island, and insular Newfoundland. Overall, diamondback moth populations showed high generational mortality (> 90%) in all provinces, although parasitism levels were generally low. The net reproductive rate of increase in diamondback moth was less than 1.0 (populations declined) in both years in British Columbia and in each of two years in Newfoundland and Ontario, but it was greater than 1.0 in all three years in Prince Edward Island. Lower parasitism levels were found in Prince Edward Island (3.0–6.3%) compared with other provinces (8.4–17.6%, except one year in British Columbia). Diadegma insulare was the main larval parasitoid found; it was present in all provinces. Microplitis plutellae was present in all provinces except British Columbia. Oomyzus sokolowskii was found in British Columbia and Ontario. The parasitoid community documented from sentinel sampling was less diverse than that found through destructive sampling. Hypotheses are provided to explain the presence of major parasitoids. Increasing larval parasitism would have the largest effect on diamondback moth population growth in Canada.

Over the past 20 years, ash trees (Oleaceae) in parts of the western United States of America and Canada have been subject to infestations with the psyllid Psyllopsis discrepans (Flor) (Hemiptera: Psyllidae). Infested trees show a series of symptoms, including pseudogalls, canopy loss, and in many cases, tree death. This is an expensive problem for urban forests, particularly in the context of emerald ash borer (Coleoptera: Buprestidae) and Dutch elm disease (Ophiostomataceae), which also impact the diversity of urban forests. This paper presents results from a study on the efficacy of two tree-injected insecticides, Orthene® (acephate) and TreeAzin® (azadirachtin). Trees were treated with these insecticides, and egg and adult psyllids were counted. In addition, canopy cover and severity of pseudogalling were visually assessed. Orthene reduced canopy loss and severity and amount of pseudogalling compared to what occurred on control trees; however, there were more eggs on Orthene-treated trees, indicating that any potential benefit was offset by higher egg counts after treatment. Due to the rapid decline of the ash trees, TreeAzin could not be successfully injected.

This study investigated the potential of the parasitic tachinid fly, Pentatomophaga latifascia (Diptera: Tachinidae), as a biological control agent against adult brown marmorated stink bug, Halyomorpha halys (Hemiptera: Pentatomidae), in Akita Prefecture, northern Japan. Overwintering adults of H. halys were collected from a hibernation site from 2017 to 2019, and the adults were reared at 20 °C in the following spring of each year. Almost all female and male adults parasitised by P. latifascia survived only a few days after the larvae of P. latifascia emerged, and none of the females laid eggs. Emergence of larval P. latifascia from the adults was observed from 18 days after the start of rearing, and all emergence was completed within a 20-day period. The parasitism rate of the field population of overwintered H. halys adults was about 10% each year, and the survival rates of adults of both sexes decreased by about 10%, in synchrony with the time of emergence of larval P. latifascia. These observations indicated that P. latifascia contributed to a decrease in the population density of post-overwintering adult H. halys, at least in early spring.

Leuctra Stephens, 1836 is the fourth most speciose genus of Plecoptera (Leuctridae) east of the Rocky Mountains with 31 recognised species, trailing only Isoperla Banks, 1906 (58), Allocapnia Claassen, 1928 (47), and Perlesta Banks, 1906 (34). Although Leuctra females are described in taxonomic literature, they are difficult to morphologically distinguish among regional congeners, and identifications are often made through inference only (i.e., presence of males). This is particularly problematic in the Appalachian Mountains of the United States of America, which host numerous Leuctra species. We sampled the stonefly fauna of Mount Mitchell, western North Carolina, United States of America, from April to October 2019. The mitochondrial cytochrome C oxidase subunit 1 gene was sequenced for 39 adult males and 239 adult females of Leuctra. This allowed us to confidently place species names on all of the latter individuals. Phylogenetic tree- and genetic distance–based methods consistently grouped females with males for nine recognised species. Two separate L. ferruginea (Walker, 1852) operational taxonomic units were recognised, albeit with low divergence values, and an additional undetermined Leuctra was identified based solely on females. Digital stereomicroscope images were taken from females of each species unit to identify variation among and between species. This approach allowed for a more robust assessment of regional biogeographic patterns.

In-depth understanding of malaria transmission dynamics in a region can be assessed by identifying the vector populations of infected mosquitoes, Anopheles spp. (Diptera: Culicidae), and by quantifying the infectiousness extent. In this study of malaria transmission dynamics relating to vector incrimination in three districts of Odisha, India – hyperendemic Kalahandi, mesoendemic Bargarh, and hypoendemic Cuttack – we examined how quality and quantity of plasmodial infection rates vary among mosquito species and their organs and among districts. The minimum infection rate of Plasmodium falciparum sporozoite for Anopheles culicifacies was highest in Kalahandi and nil in Cuttack. However, for A. annularis, the rate was highest in Cuttack, followed by Kalahandi and Bargarh. In Kalahandi, the gland-positive rate was higher for A. culicifacies, but in Cuttack, it was higher for A. annularis. To quantify plasmodium infection in salivary glands and guts of anopheline vectors, quantitative polymerase chain reaction was performed. We observed higher parasite density in glands than in guts of vector mosquitoes in the three districts. The findings demonstrate that plasmodium-infected vectors preferentially bind sporozoites to salivary glands in the three study areas. The results improve understanding of infection status within malaria vectors and how parasite population density may affect transmissibility, which will, in turn, provide baseline evidence to develop intervention measures.

The parasitic mite Varroa destructor (Mesostigmata: Varroidae) is the main culprit of honey bee (Hymenoptera: Apidae) colony mortality in Ontario, Canada. Most beekeepers use synthetic acaricides to control V. destructor infestations in their colonies, but the use of these products increases the risk of V. destructor developing resistance to the active ingredients, which is a growing concern. This study sought to determine the efficacy of three synthetic acaricides approved for use in Canada for control of V. destructor infestations, amitraz (Apivar™), tau-fluvalinate (Apistan®), and flumethrin (Bayvarol®), using the Pettis test. The mite mortality rate in populations of V. destructor differed for the acaricides tested. Amitraz caused a significantly higher mite mortality rate (92%) than flumethrin (78%) and tau-fluvalinate (72%) did. Amitraz was classified as “mostly effective” (90–97%), whereas flumethrin and tau-fluvalinate were classified as “minimally effective” (< 80%) for V. destructor control in the mite populations studied. Variation in mite mortality due to acaricide exposure was observed between apiaries and regions. The results highlight the importance of periodically assessing the varroacidal activity of acaricides to inform decisions to control the parasite when implementing integrated pest management strategies.

A total of eight species of thrips (Thysanoptera: Thripidae) have been listed as banana pests in Brazil. Their feeding and oviposition behaviour on these fruits damage their appearance in ways that can impair commercial value. As a result, taxonomic studies that seek to correctly identify thrips can positively impact the cultivation of bananas. Many earlier records of banana thrips in Brazil consist of doubtful identifications or untraceable reports. In this paper, the identification of these banana pests in Brazil is revised and an illustrated identification key is provided. The specimens examined were collected over a period of 10 years from the most representative banana-growing areas in Brazil. Seven banana thrips in Brazil are now recognised: Bradinothrips musae (Hood), Chaetanaphothrips orchidii (Moulton), Danothrips trifasciatus Sakimura, Elixothrips brevisetis (Bagnall), Frankliniella brevicaulis Hood, Frankliniella parvula Hood, and Hoodothrips lineatus (Hood). Chaetanaphothrips orchidii and Danothrips trifasciatus are recorded for the first time as causing damage to banana crops in Brazil. In addition, the following three species are considered misidentifications and should be disregarded as banana pests in Brazil: Frankliniella fulvipennis Moulton, Hercinothrips bicinctus (Bagnall), and Hercinothrips femoralis (Reuter).

Hydaticus pacificus conspersus Régimbart, 1899 (Coleoptera: Dytiscidae), is currently considered “endangered,” according to the national Red List of Japan. Herein, the developmental period of the immature stages of H. pacificus conspersus during laboratory rearing is described in detail for the first time. We found that this species deposits eggs not only on aquatic plants but also on the surface of driftwood. The observed durations of developmental stages were as follows: egg period – 3 days; first instar – 1–2 days (1.7 ± 0.5); second instar – 1–4 days (2.4 ± 0.6); third instar – 4–7 days (5.0 ± 0.7 days); and construction of a pupal chamber to emergence: 8–13 days (9.6 ± 0.8). Based on these observed results, H. pacificus conspersus has one of the shortest larval developmental periods among the Dytiscidae species. The short larval period and the ability to lay eggs on substrates other than plants may be an adaption of the species to increase reproductive success in unstable environments.

Population density affects the behaviour and population dynamics of insects, but the nature of that effect may depend on the degree of sociality. We experimentally manipulated initial population density of a subsocial insect, the Madagascar hissing cockroach, Gromphadorhina portentosa Schaum, 1853 (Blattodea: Blaberidae), to determine its effect on vital rates and population dynamics. In accordance with the predicted Allee effect, we hypothesised that intermediate cockroach population density will increase per capita birth rates and cause a higher population growth rate relative to smaller and larger population densities. After tracking 12 experimental populations (three replicates of four initial population densities) for 15 months, we found evidence of Allee effects in this insect. Per capita birth rates showed a quadratic response, with rates highest at intermediate population densities, suggesting a component Allee effect. Contrary to expectations for a demographic Allee effect, population growth rates showed negative density dependence. The proportion of adult females in the population increased with population density, but the mechanism for this increase is not known. Our findings provide evidence for at least one form of Allee effect in G. portentosa and shows a possible connection between subsocial behaviour and population-level responses.