The genus Saltisedes Kubota, 1944 (Coleoptera: Staphylinidae: Pselaphinae: Tmesiphorini) is redefined and three new species are described and illustrated: S. hainanensis Yin and Nomura, new species (China), S. kojimai Nomura and Yin, new species (Japan), and S. yahiroi Nomura and Yin, new species (Malaysia). Saltisedes brunneus Kubota, 1944 (Japan), the only previously known species is redescribed. Stethotaphrus Newton and Chandler is placed as a junior synonym of Saltisedes, the placement results in the following new combinations: Saltisedes clavatus (Raffray, 1882), new combination, Saltisedes hamotoides (Schaufuss, 1882), new combination, Saltisedes javanicus (Raffray, 1882), new combination, Saltisedes longispina (Raffray, 1903), new combination, and Saltisedes weiri (Chandler, 2001), new combination. A list of known Saltisedes species is included and a key to the species from continental Asia and Japan is presented.

In this study, we analysed the applicability of DNA barcodes for delimitation of 79 specimens of 13 species of nonbiting midges in the subfamily Tanypodinae (Diptera: Chironomidae) from São Paulo State, Brazil. Our results support DNA barcoding as an excellent tool for species identification and for solving taxonomic conflicts in genus Labrundinia. Molecular analysis of cytochrome c oxidase subunit I (COI) gene sequences yielded taxon identification trees, supporting 13 cohesive species clusters, of which three similar groups were subsequently linked to morphological variation at the larval and pupal stage. Additionally, another cluster previously described by means of morphology was linked to molecular markers. We found a distinct barcode gap, and in some species substantial interspecific pairwise divergences (up to 19.3%) were observed, which permitted identification of all analysed species. The results also indicated that barcodes can be used to associate life stages of chironomids since COI was easily amplified and sequenced from different life stages with universal barcode primers.

Research interest in the Arctic is accelerating because of observed and anticipated dramatic climate change and its impacts on societies and ecosystems. Arthropods form a major part of the terrestrial species diversity in the Arctic, and are particularly sensitive to changes in the abiotic environment. Hence, increased research activity on Arctic arthropods would help towards conservation of Arctic biodiversity as well as in understanding the role of Arctic arthropods in ecosystem functioning. In this introduction to the special issue on Arctic entomology in the 21st century, we identify trophic interactions, biodiversity assessments, and taxonomic revisions as three important research fields in Arctic entomology. We also point to ways in which Arctic entomology could take advantage of recent developments in other research fields and we place the contributions to the special issue in a broader context. Arthropods form ideal model organisms in global change studies and there is a particular need for entomological studies from the dramatically changing Arctic. It is our hope that the papers within this special issue will be a valuable source of inspiration and may stimulate novel insights and achievements in Arctic entomology during the 21st century.

Bark beetles (Coleoptera: Curculionidae: Scolytinae) play important roles in temperate conifer ecosystems, and also cause substantial economic losses. Although their general life histories are relatively similar, different species vary markedly in the physiological condition of the hosts they select. Most of ∼6000 known species colonise dead or stressed trees, a resource they share with a large diversity of insects and other organisms. A small number of bark beetle species kill healthy, live trees. These few are of particular interest as they compete directly with humans for resources. We propose that tree killing evolved when intense interspecific competition in the ephemeral, scarce resource of defence-impaired trees selected for genotypes that allowed them to escape this limitation by attacking relatively healthy trees. These transitions were uncommon, and we suggest they were facilitated by (a) genetically and phenotypically flexible host selection behaviours, (b) biochemical adaptations for detoxifying a wide range of defence compounds, and (c) associations with symbionts, which together aided bark beetles in overcoming formidable constitutive and induced host defences. The ability to detoxify terpenes influenced the evolutionary course of pheromonal communication. Specifically, a mate attraction system, which was exploited by intraspecific competitors in locating poorly defended hosts, became a system of cooperative attack in which emitters benefit from the contributions responders make in overcoming defence. This functional shift in communication was driven in part by linkage of beetle semiochemistry to host defence chemistry. Behavioural and phenological adaptations also improved the beetles’ abilities to detect when tree defences are impaired, and, where compatible with life history adaptations to other selective forces, for flight to coincide with seasonally predictable host stress agents. We propose a conceptual model, whereby the above mechanisms enable beetles to concentrate on those trees that offer an optimal trade-off between host defence and interspecific competition, along dynamic gradients of tree vigour and stand-level beetle density. We offer suggestions for future research on testing elements of this model.

A new species of gall midge, Stenodiplosis phragmicola Sinclair and Ahee (Diptera: Cecidomyiidae), is described. The host plant, Phragmites australis (Cavanilles) Trinius ex Steudel (Poaceae), is a tall, widely distributed emergent aquatic macrophyte. An introduced subspecies of the plant is considered invasive in North America (although a native subspecies also occurs). Insect specimens were collected during September 2010 and 2011 from the florets of common reed at 12 sites around Peterborough, Ontario, Canada. Preliminary data on ecological interactions between the plant and the insect are presented. Out of 2400 florets sampled, 9.5% were host to larvae of S. phragmicola. Three sites had much higher rates of infestation, with between 20% and 30% florets, and up to 100% of sampled shoots containing fly larvae. The largest stands in the sample all hosted fly populations and there was a positive association between the reproductive output of P. australis stands (measured as the average inflorescence mass per stand) and the proportion of shoots per stand containing larvae. The occurrence of S. phragmicola on the native subspecies of P. australis is also documented. Insects that consume reproductive structures of the common reed have not previously been reported from the plant's introduced range in North America.

New data on forewing microtrichial patterns are presented. Nineteen species representing 19 genera and seven subfamilies of Afrotropical Scutelleridae are investigated using scanning electron microscopy. Four types of microtrichial patterns are recognised. The taxonomic importance of these structures in the Scutelleridae is discussed.

Larval morphology of the monogeneric subfamily Coptotominae (Coleoptera: Dytiscidae) is described and illustrated in detail, with particular emphasis on morphometry and chaetotaxy. Larvae of Coptotomus Say are unique within Dytiscidae in the presence of tracheal gills on the abdominal segments I–VI, a short bifid horn or nasale in instar I, long spinulae on the urogomphus in instar I, and rows of natatory setae on both the internal and external margins of the urogomphus in instars II and III. A cladistic analysis based on 125 larval characters sampled among representatives of other dytiscid subfamilies supports a sister-group relationship between Coptotominae and Laccophilinae based on the shared absence of setae LA10 and LA12 on the second labial palpomere and of pore ABc on the abdominal segment VIII. The clade Coptotominae + Laccophilinae resolved as sister to Lancetinae, all three subfamilies sharing the presence of an unusually low number of lamellae clypeales in the first instar (a condition called four-peg-pattern), postulated to have evolved secondarily within Dytiscidae.

The High Arctic represents a unique environment, an environment from where knowledge is limited and which is currently experiencing rapid change. The archipelago of Svalbard in the European High Arctic possesses a terrestrial and freshwater invertebrate fauna that is distinctive and diverse. However, the majority of studies concentrate on the fauna of the comparatively mild west coast. Very few investigations of the colder east coast exist. Furthermore, scientific investigations are relatively recent. Scientific records of the terrestrial invertebrate fauna begin in the mid-19th century with species inventories and community descriptions but experimental field-based studies and physiological investigations did not commence until the 1980s. Some 570 articles consider this fauna, 54% of which have appeared since 1990. There is hence a dramatic and rapid increase in our understanding, which is not only improving our comprehension of Arctic ecosystem functioning but also providing a baseline for environmental change studies. Due to a largely pristine environment, a political focus and relative ease of logistics, Svalbard is set to become a focus of such studies. This article considers the state of knowledge of the terrestrial and freshwater invertebrate fauna of Svalbard, current research, and discusses the threats to the distinctive communities.

Photoperiods influence diapause beyond the maternal generation in Cotesia vestalis (Haliday) (Hymenoptera: Braconidae). The sizes, 20-hydroxyecdysone (20E), and juvenile hormone III (JH III) contents in the G1 diapausing prepupae, G0 nondiapausing prepupae, adults, and G1 eggs from C. vestalis cultures reared under three photoperiods (8:16 hours light:dark, 12:12 hours light:dark, and 16:8 hours light:dark) were measured to investigate the hormones’ roles on maternal information transmission and diapause regulation. Results showed that the body size of G1 diapausing prepupae was significantly larger than that of G0 nondiapausing prepupae. The sizes of G0 prepupae, female abdomens, and G1 eggs under eight-hour light were significantly larger than those under 16-hour light. The 20E content in diapausing prepupae was significantly lower than that in nondiapausing prepupae, whereas JH III content did not show significantly difference under the same photoperiod. The 20E content in maternal prepupae, mated females and G1 eggs decreased as the light period was reduced. Juvenile hormone III contents in G0-mated females and G1 eggs (after oviposition) under three photoperiods showed no significant differences. These findings suggest that 20E may play a critical role in diapause regulation of C. vestalis, and be used as a maternal environmental message to be transmitted to the next generation.

A new rove beetle, Sinanthobium daohugouense, new genus, new species, is described and illustrated on the basis of a tiny impression fossil from the Middle Jurassic Jiulongshan Formation at Daohugou, Inner Mongolia, China. The new genus is placed in the subfamily Omaliinae (Coleoptera: Staphylinidae), tentatively in the Recent tribe Anthophagini. The first find of a definitive omaliine beetle from the Middle Jurassic of China provides direct evidence on the origin and early evolution of Omaliinae.

Alloxysta Förster, 1869 (Hymenoptera: Figitidae) type material of 19 nominal species deposited in the Canadian National Collection of Insects (Ottawa, Ontario, Canada) and the United States National Museum of Natural History (Washington, District of Columbia, United States of America) were studied. Nine species are treated as valid: A. australiae (Ashmead, 1900), A. commensuratus Andrews, 1978, A. japonicus (Ashmead, 1904), A. lachni (Ashmead, 1885), A. longiventris Baker, 1896, A. minuscula Andrews, 1978, A. nothofagi Andrews, 1976, A. vandenboschi Andrews, 1978, and A. xanthopsis (Ashmead, 1896). The following synonymies are established: A. affinis (Baker, 1896) and A. quebeci Andrews, 1978 junior synonyms of A. castanea (Hartig, 1841); A. alaskensis Ashmead, 1902 and A. coniferensis Andrews, 1978 junior synonyms of A. macrophadna (Hartig, 1841); A. bicolor (Baker, 1896) and A. anthracina Andrews, 1978 junior synonyms of A. obscurata (Hartig, 1840); A. dicksoni Andrews, 1978 junior synonym of A. pilipennis (Hartig, 1840); and A. leguminosa (Weld, 1920), A. megourae (Ashmead, 1887), and A. rauchi Andrews, 1978 junior synonyms of A. brevis (Thomson, 1862). The type material of A. schlingeri Andrews, 1978 and A. halli Andrews, 1978 could not be found and we consider them as nomina dubia. Alloxysta vandenboschi Andrews is removed from synonymy with A. obscurata and considered a valid species. Comments on the type material are given. Complete redescriptions and images are presented for the valid species.

The mountain pine beetle Dendroctonus ponderosae Hopkins (Coleoptera: Curculionidae) kills its hosts by attacking en masse and overwhelming tree defences. Young adult beetles completing development under the bark may have the opportunity to mate with siblings or with brood from adjacent galleries prior to emerging from the natal host tree. We investigated the incidence of preemergence mating among female beetles at two locations in the recently expanded range of the insect in northern Alberta, Canada. Female beetles emerging from under the bark late in the emergence period were more likely to be mated upon emergence than beetles that emerged earlier. Delaying emergence of brood adults once they were at the teneral adult stage had little effect on the incidence of preemergence mating. The frequency of preemergence mating varied from 3–12% among female beetles. This is higher than the 1–2% reported in other studies within the historic range of the mountain pine beetle. Reasons for these differences are discussed.

Five artificial plant models mimicking potato plants, each having different and increasing numbers of structural components, were used to observe individual adult Colorado potato beetles (Leptinotarsa decemlineata (Say); Coleoptera: Chrysomelidae) over a period of 6 hours. The objective was to determine if plant architecture affected residency time, within plant dispersal, and distribution of the species. The number of transitions between sections, the time spent on each section, the residency time on each model, and the proportion of individuals walking off were recorded. Results showed a positive relationship between the proportion of beetles remaining after 6 hours and the number of connections on respective models. The unexpectedly long residency on all but the simplest model in spite of the absence of food indicates that architectural complexity had an impact on beetle retention. Dispersal activity and residency time were heavily skewed towards the top of models. Beetles exposed to positive light gradients of different intensities and a negative light gradient showed that a phototactic response could explain much of the dispersal pattern to the upper model sections. Results show that manipulation of plant structure remains an option for managing the beetle but will require further research on the contribution of heterogeneity and scale to residency time.

Arctia olschwangi Dubatolov, formerly known only from Arctic Siberia, Russia, is recorded from northern Alaska, United States of America. Distinguishing characters between northern populations of Arctia brachyptera Troubridge and Lafontaine, Arctia caja (Linnaeus), A. olschwangi Dubatolov, and Arctia opulenta (Edwards) are discussed. Arctia brachyptera Troubridge and Lafontaine is hypothesised to be a subspecies of A. olschwangi Dubatolov but more specimens need to be examined before this taxonomic change is made.

Electroborus brighti, new genus, new species (Coleoptera: Curculionidae: Scolytinae) is described based on two specimens from Dominican amber, which represents the first Hylesinini found in Dominican amber. A phylogenetic analysis of 24 Hylesinini species and a Strombophorus Hagedorn species based on morphological characters suggests E. brighti is not related to the Neotropical genus Phloeoborus Erichson, but shares a close affinity to African Hylesinini genera. The discovery of this new genus adds to the evidence that tropical South America and Africa shared similar faunas throughout evolutionary history. Although many Old World taxa have become extinct in the New World, the existence of E. brighti among Recent faunas is a possibility, given that the South American and African scolytine faunas are relatively poorly studied.

The styli, often called the aristae, of the antennae of adult Sepedon fuscipennis Loew (Diptera: Sciomyzidae) are shown to possess mechanosensilla, the number and arrangement of which differ between the sexes. It is suggested that the mechanosensilla provide sensory input to the female regarding the touching, or appositioning, of her styli by the male with his forelegs during copulation. Among the Sciomyzidae, S.fuscipennis males are unique in appositioning the antennae of the female during mating. Large clusters of pollen found on the styli of both sexes suggest that mechanosensilla and chemosensilla also provide sensory information about potential sources of food such as nectar (i.e., carbohydrates).

Apalus bimaculatus (Linnaeus) (Coleoptera: Meloidae) is a beetle currently managed for conservation in Sweden. The species inhabits at-risk ephemeral and patchily distributed sandy habitats. However, little is known about its ecology and the factors important for its distribution. We censused 158 discrete sand patches within 31 potential sites for A. bimaculatus and examined which environmental variables predicted the probability of finding the beetle. Apalus bimaculatus was found at 17 sites, its presence at sand-patch scale was positively correlated with sand-patch area, sand temperature, and medium-sized sand grains. Although the beetle is assumed to be a parasite on the solitary bee, Colletes cunicularius (Linnaeus) (Hymenoptera: Colletidae), presence of the bee was a very weak predictor for A. bimaculatus, while other sand-living Hymenoptera were a strong predictor. At site-level scale, the beetle was positively correlated with total amount of sandy habitat and presence of sand-living Hymenoptera. Our study suggests that management strategies for this species should not consider sandy habitats equally. Rather, management efforts should focus on maintaining sites with larger total sandy areas, creating larger sand patches with medium-grained sand and a high degree of sun exposure. We also highlight that biotic interactions between the beetle and sand-living Hymenoptera are still poorly understood but potentially important for successful A. bimaculatus management.

Arctic arthropods are essential prey for many vertebrates, including birds, but arthropod populations and phenology are susceptible to climate change. The objective of this research was to model the relationship between seasonal changes in arthropod abundance and weather variables using data from a collaborative pan-Canadian (Southampton, Herschel, Bylot, and Ellesmere Islands) study on terrestrial arthropods. Arthropods were captured with passive traps that provided a combined measure of abundance and activity (a proxy for arthropod availability to foraging birds). We found that 70% of the deviance in daily arthropod availability was explained by three temperature covariates: mean daily temperature, thaw degree-day, and thaw degree-day2. Models had an adjusted R2 of 0.29–0.95 with an average among sites and arthropod families of 0.67. This indicates a moderate to strong fit to the raw data. The models for arthropod families with synchronous emergence, such as Tipulidae (Diptera), had a better fit (average adjusted R2 of 0.80) than less synchronous taxa, such as Araneae (R2 = 0.60). Arthropod abundance was typically higher in wet than in mesic habitats. Our models will serve as tools for researchers who want to correlate insectivorous bird breeding data to arthropod availability in the Canadian Arctic.

Preference-performance hypothesis in host selection by herbivorous insects predicts selective oviposition on plant on which the offspring maximise fitness. The seed parasitoid wasp, Macrodasyceras hirsutum Kamijo (Hymenoptera: Torymidae) selectively lays the eggs into the fertilised seeds of Ilex integra Thunberg (Aquifoliaceae). Only one larva develops in a seed. Therefore, the hypothesis predicts a uniform distribution pattern of wasp eggs among fertilised seeds. Dissection of 531 berries showed that M. hirsutum deposited one to five eggs into a fertilised seed. Iwao's patchiness regression suggested a uniform distribution pattern of M. hirsutum eggs among fertilised seeds at the scales of tree and berry and their random distribution pattern among berries at the tree scale. Destroying the connection of seeds within berries revealed that female wasps randomly selected berries for oviposition in most trees. Generalised linear mixed models showed that the number of fertilised seeds in a berry could not explain the number of eggs in a seed but could explain the number of eggs in a berry. Therefore, this study shows that the wasp females do not distinguish between berries with different numbers of fertilised seeds but distinguish between seeds harbouring different numbers of eggs, which supports the hypothesis.