Lyme borreliosis (LB), also known as Lyme disease, is emerging as a serious tick-borne illness across Canada. More than three decades of research on LB in North America and Europe have provided a large, complex body of research involving well-documented difficulties at several levels. However, entomologists are well situated to contribute to resolving some of these challenges. The central pathogen in LB, the spirochete Borrelia burgdorferi Johnson et al., includes numerous genospecies and strains that are associated with different disease symptoms and distributions. The primary vectors of LB are ticks of various Ixodes Latreille species (Acari: Ixodida: Ixodidae), but questions linger concerning the status of a number of other arthropods that may be infected with B. burgdorferi but do not transmit it biologically. A variety of vertebrates may serve as reservoirs for LB, but differences in their ability to transmit LB are not well understood at the community level. Persistent cystic forms of and immune-system evasion by B. burgdorferi contribute to extraordinary challenges in diagnosing LB. Multiple trade-offs constrain the effectiveness of assays like ELISA, Western blot, polymerase chain reaction, and microscopic visualization of the spirochetes. Consequently, opportunities abound for entomologists to contribute to documenting the diversity of the players and their interactions in this devilishly complex disease.

Sexual dimorphism in size and shape has been studied in a wide range of organisms, but intraspecific variation in sexual dimorphism remains largely unexplored. In many parasitoid species the diversity of morphological-variation patterns within species is complicated by host effects. It is not known whether the magnitude and direction of sexual size dimorphism can be affected by the developmental environment (i.e., different host species). In this study we explored patterns of sexual dimorphism in size and shape in the aphid parasitoid Ephedrus persicae Froggatt. The analyzed sample consisted of 83 females and 54 males reared from five species of host aphids (Hemiptera: Aphididae) from various areas of the Palaearctic region. The most notable result of the study is that E. persicae displays divergent patterns of sexual dimorphism in body size and wing size: females have larger bodies than males, but males have larger wings. Our analysis of wing size and wing shape also showed significant within-species variation in the degree and pattern of sexual dimorphism. Variation in wing shape between the sexes seems to be more conserved than variation in wing size. Variation in wing shape is influenced predominantly by host (biotype) and to a lesser extent by sexual dimorphism within a biotype.

Species of Braggia Gillette and Palmer (Hemiptera: Aphididae: Aphidinae: Aphidini) feed on various buckwheat, Eriogonum Michx. (Polygonaceae), species in western North America. Two new species, Braggia columbiana Pike n. sp. from Washington and Oregon and Braggia longicauda Pike n. sp. from Washington, Oregon, and northern California, are proposed. Descriptions, diagnoses, illustrations, mitochondrial cytochrome c oxidase subunit 1 “barcode” sequences, a key to the species of Braggia, and notes on biology, distribution, and parasitoid associations are provided.

Adult Asian long-horned beetles, Anoplophora glabripennis (Motschulsky) (Coleoptera: Cerambycidae: Lamiinae), were discovered in Ontario, Canada, in 2003 in the vicinity of a commercial warehouse. Trees were heavily scarred with signs of attack and larvae and adult beetles were common, suggesting that there had been multiple generations at the site. We amplified 16 microsatellite loci from 326 beetles to examine genetic diversity in this population. Based on Hardy—Weinberg equilibrium, 6 of 16 loci were monomorphic and 8 were not, indicating nonrandom mating. Measures of microsatellite genetic diversity and mitochondrial DNA haplotype diversity were significantly lower than those in A. glabripennis from China and Korea but were not significantly different from those in the New York City population. The proportion of different multilocus genotypes in the Ontario population was lower than in the populations in New York City and Linden, New Jersey. These results suggest that limited genetic diversity in the Ontario population has not hampered reproduction of this invasive insect. This genetic signature is common in other invasive species, likely because a population is founded by a few closely related individuals, or a large founding population suffers subsequent genetic bottlenecks.

Host preferences and reproductive performance of the juniper bark beetle, Phloeosinus bicolor (Brulle), on logs from different parts of the bole of indigenous Cupressus sempervirens L. (Cupressaceae) and exotic C. arizonica Greene and C. sempervirens var. atlantica (Gaussen) Silba were experimentally studied in the field and laboratory in Tunisia. Attack densities were around 1/dm² in the field, fecundity was 10–25 eggs per female's gallery, with a sex ratio close to 1. There was no effect of cypress taxon or log category on host selection or attack parameters (attack density, density of systems, density of galleries, rate of successful attacks), although values for C. sempervirens tended to be higher than those for C. arizonica. Reproductive performance (gallery length and fecundity) was highest in C. arizonica and lowest in C. sempervirens var. atlantica, with C. sempervirens in an intermediate position; egg densities did not differ. Gallery length and fecundity showed a significant linear correlation but were lower in C. sempervirens var. atlantica than in the other two taxa. Thus there seems to be no relationship between host preference and host suitability in P. bicolor: its ability to choose and oviposit in various cypress taxa fits with its polyphagous status.

Kleptoparasitism (one organism stealing prey from another) is especially common in birds. Avian kleptoparasites should be especially likely to target insects such as digger wasps (Hymenoptera: Sphecidae) that occur in large aggregations and repeatedly deliver large prey to the same nesting site. We document kleptoparasitism of digger wasps (Sphex pensylvanicus L.) by sparrows (Passer domesticus (L.)) and catbirds (Dumetella carolinensis (L.)). During summer 2008, we observed 697 wasp provisioning attempts (return of a prey-laden wasp to a marked nesting site) in a mown field. One-third (244/697) of attempts were intercepted by birds, primarily sparrows, which increased their hourly total number and hourly number of successful attacks per capita. Wasps maintained a consistent rate of successful provisioning attempts but may not have been able to do so indefinitely. Energetic costs related to kleptoparasitism may exert strong selection pressures on affected digger wasps.

We investigated parasitism of the purple loosestrife beetle, Neogalerucella calmariensis (L.) (Coleoptera: Chrysomelidae), an introduced weed biological control agent, at 13 sites in eastern Ontario and western Quebec, Canada. Beetles were parasitized by gregarine gut protozoans (Apicomplexa: Eugregarinida) and much less commonly by nematodes (Nematoda: probably Mermithidae) and ectoparasitic mites (Acari: Erythraeidae). Female beetles had more gregarines than did males and the gregarine load was marginally higher in individuals from the original release sites than in individuals from recently colonized sites. Despite its overall success as a biological control agent, N. calmariensis harbours a substantial parasite load.

A 2-year field study was conducted using sentinel traps to determine the seasonal distribution of the egg parasitoid (Hymenoptera) complex attacking hemlock looper, Lambdina fiscellaria (Guenée), throughout eastern Quebec and western Newfoundland. Hemlock looper populations remained low in all areas over the course of the study. Parasitism of eggs in sentinel traps was generally lower in fall than in spring. Trichogramma Westwood (Trichogrammatidae) as well as Telenomus flavotibiae Pelletier and an unidentified species of Telenomus Haliday (Scelionidae) only parasitized eggs in the fall. Telenomus droozi Muesebeck only parasitized eggs in the spring, whereas T. coloradensis Crawford attacked eggs during both fall and spring. Telenomus coloradensis was the most abundant parasitoid species collected and was far more abundant in spring than in fall collections.

A sequential decision plan was developed for controlling larvae of the bertha armyworm, Mamestra configurata Walker (Lepidoptera: Noctuidae), in canola (Brassica napus L. and B. rapa L., Brassicaceae), using 0.25 and 0.5 m² sampling units. Fields in Manitoba were sampled from 1980 to 1994 to determine minimum sample sizes and upper and lower cumulative larval counts at three economic thresholds. Taylor's power law described most of the variation between mean larval density and variance for 0.25 m² (r² = 0.926) and 0.5 m² (r² = 0.924) samples. Larvae were found to have a moderately clumped distribution in canola (b = 1.42). Levels of precision (D₀) varying from 0.15 to 0.25 caused minimum sample sizes to vary between 6 and 21 for the 0.5 m² samples to between 9 and 31 for the 0.25 m² samples, for an economic threshold of 16–24 larvae/m² (P = 0.20). Mean sampling times ranged from 40–108 for the 0.25 m² samples to 49–126 min for the 0.5 m² samples. The sampling plan for the 0.25 m² samples was verified in 18 fields in 2006 and 2007. A correct decision was made in 87% (D₀ = 0.25), 91% (A) = 0.20), and 94% (D₀ = 0.15) of the fields when the recommendation was to spray if a decision could not be reached after a second sampling. The mean number of samples needed for making a decision was 14 (D₀ = 0.25), 19 (D₀ = 0.20), and 32 (D₀ = 0.15). We recommend that growers use a precision level of 0.20 to minimize error rates and sampling effort. In most years, the minimum number of 0.25 m² samples per field that growers would need to take is 14–17.