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 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.

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.

Aphid species colonising ferns belong to the subfamily Aphidinae (Hemiptera: Aphididae) and the majority of these to the tribe Macrosiphini. A new genus in this tribe and its type species: Gibbomyzus pteridophytorumnew genus, new species, are established. Apterous and alate viviparous females are described from specimens collected on Blechnum buchtienii Rosenstock (Blechnaceae) in Costa Rica and on Pteridium aquilinum (Linnaeus) Kuhn (Dennstaedtiaceae) and an unidentified fern in Mexico. The taxonomic validity of the two new taxa is discussed based on morphological and molecular data. Morphologically, the new genus is compared with genera with swollen siphunculi recorded in the New World, and also with genera living on ferns anywhere in the world. The identification key by Blackman and Eastop to aphids living on ferns is modified. Molecular analyses were carried out on the sequences of a fragment of the mitochondrial gene encoding for cytochrome c oxidase subunit 1 and of a fragment of the nuclear gene encoding elongation factor-1 alpha. In both analyses, G. pteridophytorumnewspecies sequences showed considerable divergence (∼4% or more) from those of 23 other species from diverse genera of Macrosiphini, supporting the conclusions of the morphological study and justifying the establishment of the new genus.

The western spruce budworm, Choristoneura occidentalis Freeman (Lepidoptera: Tortricidae), is an important pest of western North American coniferous forests, where its principal larval host is Rocky Mountain Douglas-fir, Pseudotsuga menziesii subspecies glauca (Beissner) Murray (Pinaceae). In southwestern Alberta, Canada, populations were recently discovered feeding on an unconventional host, an Engelmann spruce, Picea engelmannii Parry ex. Engelmann × white spruce, Picea glauca (Moench) Voss hybrid (Pinaceae), in a transition zone between the two major forest types characterised by these conifer species. We use molecular evidence to verify the species identity of outbreaking Choristoneura populations collected from Douglas-fir and hybrid spruces in southwestern Alberta in 2009, and characterise the larval and male moth phenology. Both mitochondrial and microsatellite markers confirmed these populations as C. occidentalis, but admixture with Choristoneura fumiferana (Clemens) (Lepidoptera: Tortricidae) was detected in some individuals. Few differences associated with separate host trees were evident in the phenology of larvae and the flight period of male moths.

The apple clearwing moth, Synanthedon myopaeformis (Borkhausen) (Lepidoptera: Sesiidae), is a day-flying species that feeds on floral nectar of many plants. In British Columbia, Canada, this invasive moth is often observed feeding on visually conspicuous showy milkweed, Asclepias speciosa Torrey (Apocynaceae). We measured the spectral efficiency of the compound eyes of S. myopaeformis in the context of their capacity to discriminate the measured spectral reflectance from inflorescences of A. speciosa, and conducted histological examination of these eyes to determine whether they possess apposition type ommatidia, as commonly observed in diurnal butterflies. Light micrographs of the compound eyes in S. myopaeformis revealed eucone apposition type ommatidia, which is consistent with the diurnal behaviour of the moth. Electroretinograms on compound eyes revealed they were particularly efficient at absorbing ultraviolet (UV) wavelengths in the 335–370 nm range and green wavelengths in the 495–560 nm range. These results support the conclusion that the compound eyes of S. myopaeformis have the capacity for dichromatic vision based on UV and green photoreceptors. However, spectral reflectance curves obtained from inflorescences and foliage of A. speciosa revealed no evidence of UV reflectance, making it less likely that colour plays a primary role in the attraction of S. myopaeformis to A. speciosa.

Artificial diet is commonly used to rear the spruce budworm, Choristoneura fumiferana (Clemens) (Lepidoptera: Tortricidae), in the laboratory. While its effect on spruce budworm performance is relatively well studied, no information exists about the influence of rearing diet on larval parasitism. In this study, spruce budworm larvae reared in the laboratory on artificial diet or balsam fir, Abies balsamea (Linnaeus) Miller (Pinaceae), foliage were introduced in the field to compare parasitism. Additionally, a laboratory choice test was conducted with the larval parasitoid Tranosema rostrale (Brischke) (Hymenoptera: Ichneumonidae). No significant influence of spruce budworm rearing diet on parasitism in the field was found. However, in the laboratory, T. rostrale attacked significantly more foliage-fed larvae. We conclude that even if initial differences in parasitism may exist between diet-fed and foliage-fed larvae in the laboratory, spruce budworm larvae reared on artificial diet can be used in field studies investigating parasitism of wild spruce budworm populations without concern that the food source would affect parasitism.

We have recently shown that firebrats, Thermobia domestica (Packard) (Thysanura: Lepismatidae), carry, and deposit with their faeces, the symbiotic bacterium Enterobacter cloacae (Jordan 1890) Hormaeche and Edwards 1960 (Enterobacteriaceae) and the symbiotic fungus Mycotypha microspora Fenner, 1932 (Mycotyphaceae), and that these microbes induce arrestment behaviour and aggregation of firebrats. Here, we tested whether giant silverfish, Ctenolepisma longicaudata Escherich (Thysanura: Lepismatidae), and common silverfish, Lepisma saccharina (Linnaeus) (Thysanura: Lepismatidae), also arrest in response to these two microbes. In dual-choice bioassays, E. cloacae arrested firebrats but not giant silverfish or common silverfish, whereas M. microspora arrested firebrats and giant silverfish but not common silverfish. As close relatives, firebrats and giant silverfish have similar microclimate and nutrient requirements and may use M. microspora as the same aggregation cue when they aggregate in hot and humid microclimates where M. microspora proliferates and breaks down cellulose. As a more distant relative to firebrats and giant silverfish, common silverfish seem to require a different as yet unknown aggregation cue or signal, possibly one that is indicative of the type of microclimate (room temperature; high humidity) they prefer.

It is unrealistic to achieve high-resolution biodiversity inventories required to support local conservation strategies over large areas; however, benchmark associations between arthropods and ecosystem classification can support landscape scale biomonitoring. We investigated habitat associations of ground-dwelling spiders (Araneae), staphylinid beetles (Coleoptera: Staphylinidae), and carabid beetles (Coleoptera: Carabidae) in three forest ecosystems in northwestern Alberta, Canada and also studied the effect of variation in depth of pitfall trap installation on catch. Composition and diversity of all three taxa were correlated with the ecosystem classification map, and 20 species were strong indicators of particular habitats. The black spruce (Picea mariana (Miller) Britton, Sterns, and Poggenburg; Pinaceae) bog supported fewer species and individuals of beetles but this trend was not observed for spiders because of natural history traits associated with their performance in this environment. Pitfall trapping biases were constant among habitats enabling proper comparison of ground-dwelling invertebrate assemblages. Three species of beetles (Agonum retractum LeConte (Coleoptera: Carabidae), Pterostichus brevicornis (Kirby) (Coleoptera: Carabidae), and Quedius velox Smetana (Coleoptera: Staphylinidae)) were disproportionally active beneath the soil surface, as catches were greater in pitfall traps with the lip situated 15–25 cm below the soil surface. Thus, even highly standardised trap placement will influence the concept of biodiversity achieved through pitfall trapping, because some target organisms are disproportionately active in subterranean zones.

In the present study, effects of body size and prey quality on reproductive attributes and longevity of two aphidophagous Coccinellidae (Coleoptera), Coccinella septempunctata (Linnaeus) and Coccinella transversalis Fabricius, have been investigated in laboratory conditions. Higher fecundity, egg fertility, and longevity were obtained in larger females of C. septempunctata on pea aphid, Acyrthosiphon pisum (Harris) (Hemiptera: Aphididae), and in C. transversalis on bean aphid, Aphis craccivora Koch (Hemiptera: Aphididae). Males of C. septempunctata survived longer than those of C. transversalis on both prey. Number of clutches was lower and clutch size was higher in early and late reproductive phase; the reverse was observed in the middle of the reproductive phase. Larger females of C. septempunctata and C. transversalis laid higher number of clutches than the smaller ones. Thus, both body size and prey quality affect reproductive performance in Coccinellidae, though size variation did not change the prey preference.

We present a case study in which we developed an adaptive delimitation technique and implemented and evaluated management of emerald ash borer (EAB), Agrilus planipennis Fairmaire (Coleoptera: Buprestidae), in the first infestation discovered in New York State, United States of America. Delimitation was accomplished using 106 girdled “sentinel” trees and management included girdling 18 clusters of trees as population “sinks” to attract EAB and concentrate larvae for removal. Weekly monitoring of traps hung in sentinel trees facilitated early detection of EAB on 12 trees and allowed deployment of additional sentinels and sinks. Sentinel trees were felled and debarked; 12 were positive for EAB larvae and the spatial extent of infestation estimated at ∼48 km2. Sinks nearest the infestation core had the highest numbers of larvae. Larval densities were significantly greater in girdled trees than in proximate ungirdled trees suggesting removal of girdled trees prior to the following year's emergence would lower local EAB densities. Sinks deployed in response to an EAB on a sentinel tree purple prism trap more than 0.6 km from the centre of the known infestation were negative for EAB indicating these would not be effective for managing an infestation of similar size and in similar habitats. This case study provides valuable information to land managers to facilitate delimitation and management of newly discovered EAB infestations.