Lyme borreliosis (LB), also known as Lyme disease, is emerging as a serious tickborne 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.

In the 20th century, five species of birch-leafmining sawflies were inadvertently introduced from Europe to North America: Heterarthrus nemoratus (Fallén), Fenusa pumila Leach, Profenusa thomsoni (Konow), Fenusella nana (Klug), and Scolioneura vicina Konow. All have been recorded at outbreak levels in North America, and three (F. pumila, P. thomsoni, and H. nemoratus) have been the targets of successful biological control programs. The most recently detected species, F. nana and S. vicina, are good candidates for future biological control in Canada. We review the biology of all five of these birch-leafmining sawflies in North America and present keys to adults, larvae, and mines to aid correct identification.

Thirty-five species of Latridiidae are reported in Atlantic Canada as a whole, 17 in New Brunswick, 14 in Newfoundland, 31 in Nova Scotia, and 14 on Prince Edward Island. Fifty-six new provincial records are reported (11 in New Brunswick, 9 in Newfoundland, 23 in Nova Scotia, 13 in Prince Edward Island). Twenty-two species are newly recorded for Atlantic Canada. Of these, Cartodere (Aridius) bifasciata (Reitter), Enicmus histrio Joy and Tomlin, Latridius consimilis (Mannerheim), Corticaria elongata (Gyllenhal), C. impressa (Olivier), C. saginata Mannerheim, Corticarina longipennis (LeConte), Melanophthalma helvola Motschulsky, and M. inermis Motschulsky are newly recorded in Canada, and C. bifasciata, E. histrio, and C. saginata are newly recorded in North America. Dienerella filiformis (Gyllenhal) is removed from the New Brunswick and Prince Edward Island lists. Corticaria dentigera LeConte is removed from the Labrador and Atlantic Provinces lists. Melanophthalma inculta Motschulsky syn. nov. and M. signata Belon syn. nov. are designated as a junior synonyms of M. inermis Motschulsky and M. picta (LeConte), respectively. Melanophthalma helvola Motschulsky is reinstated as a valid species. Lectotypes and paralectotypes of M. helvola and M. americana (Mannerheim) are designated. Approximately half of the species are adventive (16 Palaearctic, 1 Australian) and half are native (13 Nearctic, 3 Holarctic). Two species are of uncertain zoogeographic status. Although some species are synanthropic, several have colonized native habitats. Nova Scotia has the largest number of adventive species, probably as a result of trans-Atlantic shipping. New Brunswick has the fewest, at least in part because of insufficient collecting there. Early detection dates and introduction processes are discussed. The native faunas on Prince Edward Island, Cape Breton Island, and Newfoundland appear diminished (33%–40%) compared with those of the neighbouring mainland. Although all latridiids are mycetophagous, many in the region show clear habitat preferences; however, the ecological role of those species requires further investigation.

The Nearctic species of Neophyllomyza Melander are revised and descriptions, illustrations, and an identification key are provided for the two included species, N. quadricornis Melander and N. gaultin. sp. Large numbers of adults of both species were collected in emergence traps on decaying logs of sugar maple (Acer saccharum Marsh. (Aceraceae)) and American beech (Fagus grandifolia Ehrh. (Fagaceae)) in eastern Canada, indicating that the larvae of both species are saproxylic, although their exact food source is unknown. Although the two species are sympatric over much of their range and apparently use the same resources for larval development, their habits differ: N. quadricornis was collected from logs in both the early- and the advanced-decay stage from late May until September, with a peak of emergence in late June, whereas N. gaulti was reared almost exclusively from logs in the advanced-decay stage and from mid-July to mid-August. This suggests that N. gaulti is more specialized in its larval habits, which may reduce competition between the two species.

Species of the subgenus Symplecta Meigen with Arctic, or at least partly Arctic, distributions are revised. Five species are redescribed: S. (S.) novaezemblae (Alexander), S. (S.) scotica (Edwards), S. (S.) mabelana (Alexander), S. (S.) sheldoni (Alexander), and S. (S.) horrida (Lackschewitz). Two new species are described: S. (S.) edlundaesp. nov. (Northwest Territories and Yukon, Canada) and S. (S.) echinatasp. nov. (eastern Siberia, Russia). Five new synonyms are proposed: Erioptera (S.) sunwapta Alexander and Helobia intermedia Lackschewitz = S. (S.) scotica; Erioptera (S.) platymera Alexander = S. (S.) mabelana; S. (S.) rotundiloba Podenas and Gelhaus = S. (S.) sheldoni; and Erioptera (Psiloconopa) chaetophora Alexander = S. (S.) horrida. Symplecta (Symplecta) scotica and S. (S.) mabelana are restored as full species from subspecies rank. Symplecta (Symplecta) horrida, previously placed in Erioptera (Mesocyphona) Osten Sacken, is transferred to Symplecta s.s. The distinctions between S. (S.) cana (Walker) and S. (S.) hybrida (Meigen) are clarified and the sympatric and syntopic occurrences of these species are documented. A key to the species treated, and illustrations of both male and female terminalia, are provided and the distribution of each species is outlined.

Phytoplasmas are bacterial plant pathogens consisting of more than 50 phylogenetic groups that cause devastating diseases in various crops worldwide. They are obligate parasites restricted to the phloem tissue of the host plant and are transmitted from plant to plant mostly by leafhoppers (Hemiptera: Cicadellidae). They reproduce within the tissues of their insect vectors and are transferred in the salivary secretions to new host plants during feeding. Phytoplasma epidemiology involves a tritrophic relationship between the pathogen and usually several hosts and vectors. The host-plant range depends on the number of vectors, their feeding habits, and their dispersal pattern. Interactions between phytoplasmas and their vector hosts are complex and influenced by insects' vectoring abilities and the consequences of infection for vectors. In Canada, seven phytoplasma taxa have been detected in various crops. Aster yellows, the primary vector of which is the leafhopper Macrosteles quadrilineatus (Forbes), is the most common and widespread. X-disease, transmitted by at least eight leafhopper species, is economically damaging to all cultivated species of Prunus L. (Rosaceae). Clover proliferation, also transmitted by M. quadrilineatus, is the causal agent of important diseases such as clover proliferation and alfalfa witches' broom. Ash yellows and pear decline have caused economic problems for several decades, while bois noir, a quarantinable disease in Canada, was detected in Ontario and British Columbia for the first time only recently. Because of their cryptic nature, phytoplasmas are difficult to manage; quarantine measures and insecticide sprays remain the most common control measures. However, integrated pest management techniques using beneficial insects, biotechnology, and plant resistance are emerging.

Fig-pollinating wasps are phytophagous wasps that mainly use olfaction to locate their fig (Ficus L., Moraceae) hosts. To provide a morphological framework for studying agaonid olfaction, we examined the antennal sensilla of female Ceratosolen solmsi marchali Mayr by scanning and transmission electron microscopy. We identified and characterized (ultrastructure, distribution, abundance, and position) 13 types of sensilla: multiporous placoid sensilla (types 1 and 2), basiconic sensilla (types 1 and 2), basiconic capitate peg sensilla, sensilla chaetica (types 1–3), sensilla trichodea, sensilla coeloconica (types 1–3), and one specialized sensillum regarded as a sensillum obscurum. We suggest that five types are chemoreceptors because they are porous and innervated by multiple sensory neurons. Sensilla coeloconica type 1 may also function as chemoreceptors, based on external morphology. Other sensilla may be involved in mechanoreception, thermo- and (or) hygro-reception, or pressure detection. We discuss our results in relation to the lifestyle of C. solmsi marchali.

The ash leaf cone roller, Caloptilia fraxinella (Ely), is a leaf-mining moth that has recently become a significant pest of horticultural ash, Fraxinus L., species in communities throughout the western prairie provinces of Canada. The study examines the spatial and temporal within-host distribution of immature stages of C. fraxinella on green ash, Fraxinus pennsylvanica Marsh. Female C. fraxinella showed a preference for oviposition sites in the lower canopy and on the south side of the tree at the beginning and middle of the 3-week oviposition period, respectively, but no preference at the end of the period. Oviposition was constrained temporally and occurred mainly just after green ash bud flush. Immature stages were sampled throughout the growing season, and measured widths of larval head capsules showed five instars. Fourth-instar larvae disperse from the mined leaflet to a new leaflet, roll it into a cone, and pupate. Neither canopy height nor ordinal direction affected the position of larvae in the canopy, but numbers of immature stages varied by tree within a site. Female and male moths eclose from rolled leaf cones synchronously throughout the emergence period. The study provides some of the basic biological information required to design an integrated pest management program to target this emerging pest of horticultural ash trees.

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.

The European oak borer, Agrilus sulcicollis Lacordaire, a newly detected alien species in Canada, is reported from southern Ontario. This species is illustrated and diagnosed to facilitate its recognition among other North American species of Agrilus Curtis. Data are provided on its phylogenetic affinities, host plants, native distribution, and all North American records known to date. The other eight non-native Agrilus species known in North America (A. cuprescens (Ménétriés), A. cyanescens Ratzeburg, A. derasofasciatus Lacordaire, A. hyperici (Creutzer), A. pilosovittatus Saunders, A. planipennis Fairmaire, A. sinuatus (Olivier), and A. subrobustus Saunders) are briefly discussed.

By means of an integrative taxonomic approach using morphology and DNA barcodes, multiple cryptic species within Lasioglossum (Dialictus) petrellum (Cockerell) (Hymenoptera: Halictidae) were discovered. Analysis of DNA barcode sequence data from across the supposed range of L. petrellum revealed distinct genetic differences that correlate with patterns of morphological variation and geographical distribution. The most morphologically distinct pair of species had the smallest DNA-barcode gap. The taxonomic limits of L. petrellum are revised and four new species are described and illustrated: L. (D.) tuolumnensesp. nov., L. (D.) griswoldisp. nov.L. (D.) droegeisp. nov., and L. (D.) viridipetrellumsp. nov. A key to species of the “L. petrellum” group is provided.

Spalangia dozieri Burks is newly recorded as a gregarious parasitoid in the puparia of Chrysomya albiceps (Wiedemann), C. putoria (Wiedemann), Lucilia eximia (Wiedemann), and L. sericata (Meigen) (Diptera: Calliphoridae), and represents the first report of gregariousness in Spalangia Latreille. The previously unknown males of S. dozieri are described and compared with females. Males have highly modified legs and several other sexually dimorphic features that differ from those of other Spalangia species. Most of the unusual features are hypothesized to be adaptations for grasping and holding and it is suggested that males either are phoretic on adults of their dipteran hosts or, possibly, that males exhibit aggressive or other atypical behaviour toward siblings that is correlated with being gregarious. Barbados, Brazil, Dominica, St. Lucia, St. Vincent, and Trinidad are recorded as new country distribution records for S. dozieri.

Morphometric techniques, DNA mitochondrial cytochrome c oxidase subunit 1 gene (COI) barcoding, and microsatellite flanking region sequences were used to assess the reliability of suggested morphological characters in distinguishing the green apple aphid (Aphis pomi De Geer) from the spirea aphid (Aphis spiraecola Patch), and to assess variation within these species. Both molecular approaches clearly distinguished two groups corresponding to the morphologically defined species. Differences in the length of the distal rostral segment and the number of lateral tubercles were found to be robust indicators of species membership, performing as well as multivariate approaches. Among A. pomi samples, microsatellite flanking region sequences were relatively uniform, whereas A. spiraecola exhibited much variability, which suggests that North American populations of the latter species are genetically much more complex.

Sticky-band trapping experiments were undertaken in 2003–2006 to examine the host-seeking behaviour of the emerald ash borer, Agrilus planipennis Fairmaire, in woodlots in southwestern Ontario, Canada. The female proportion of A. plannipennis emerging from host logs ranged from 0.414 to 0.582. Landings on sticky-band traps varied more with the female proportion, ranging from 0.392 to 0.889, with the majority in the upper range, suggesting behavioural differences between the sexes. Correlations between landing density and tree size measured as diameter at breast height were positive or showed no relationship. In some locations more beetles were captured on the south side of the tree than on the north side; however, there was no difference between these cardinal directions at other locations. Numbers of captured beetles were never significantly greater on the north side of boles. We observed greater landing densities of adults of both sexes on traps on trees along the edges of woodlots than on trees within the woodlots. When given a choice under natural conditions, beetles landed almost exclusively on host trees (Fraxinus pennsylvanica Marsh. (Oleaceae)) rather than on other common trees species (Carya ovata (Mill.) K. Koch (Juglandaceae), Tilia americana L. (Tiliaceae), and species of Acer L. (Aceraceae)) found in the same woodlots. Our data suggest that A. planipennis make host-selection decisions while in flight rather than landing randomly. Implications for monitoring A. plannipennis using sticky-band traps and understanding its host-seeking behaviour are discussed.

The first record of a European blackberry leaf gall midge, Dasineura plicatrix (Loew), is confirmed from North America. Specimens were reared from damaged leaves of blackberry, Rubus laciniatus Willd. (thornless variety ‘Chester’), and red raspberry, R. idaeus L. (variety ‘Cascade Delight’) (Rosaceae), in southwestern British Columbia. Photographs of the damage and illustrations of the male terminalia and female ovipositor are presented to assist future determinations.

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.

The Palaearctic species Phytomyza petoei Hering is newly recorded in the Nearctic Region. The specimens were reared from cultivated mint, Menthacf. × piperita L. (Lamiaceae), in eastern Canada. This is the first Nearctic record of a Phytomyza species feeding on mint.

The oribatid mite genus Ceratozetes Berlese is represented in America north of Mexico by 21 previously described species known from forest, grassland, subarctic and arctic soils and litter, and canopy habitats. The closely related genus Ceratozetoides Shaldybina is represented in America north of Mexico only by C. cisalpinus (Berlese). Three new species of Ceratozetes from North America are described: C. biporosussp. nov. from forest habitats of southeastern North America, C. cyclopeasp. nov. from montane habitats in western North America, and C. pseudomediocrissp. nov. from forest habitats of western North America. A detailed revised diagnosis is given for Ceratozetes, Ceratozetoides, all previously described species of Ceratozetes (C. angustus (Banks), C. borealis Behan-Pelletier, C. cuspidatus Jacot, C. enodis (Ewing), C. fjellbergi Behan-Pelletier, C. gracilis Michael, C. kutchin Behan-Pelletier, C. longispinus Jacot, C. mediocris (Berlese), C. oresbios Behan-Pelletier, C. pacificus Behan-Pelletier, C. parvulus Sellnick, C. spitsbergensis Thor, C. subaquila (Ewing), C. subinconspicuus (Berlese), C. thienemanni Willmann, C. virginicus (Banks), and C. watertonensis Behan-Pelletier), and Ceratozetoides cisalpinus. Ceratozetes figuratus (Ewing) and C. zeteki (Ewing) are considered junior subjective synonyms of C. enodis (Ewing) syn. nov., and C. inupiaq Behan-Pelletier is transferred to Mycobatidae as Cyrtozetes inupiaq (Behan-Pelletier) comb. nov. New distribution records are given for Ceratozetoides cisalpinus and Ceratozetes angustus, C. borealis, C. cuspidatus, C. gracilis, C. mediocris, C. longispinus, C. oresbios, C. pacificus, C. parvulus, C. thienemanni, C. virginicus, and C. watertonensis. A diagnostic key is provided to adults of the Ceratozetes and Ceratozetoides species now known for America north of Mexico. An analysis of the systematic relationships of 23 of these species based on adult characters indicates that Ceratozetes, excluding Ceratozetoides, is paraphyletic. The clade that includes Ceratozetoides cisalpinus and 15 species of Ceratozetes includes most species for which immatures are known. One sister clade includes Ceratozetes cyclopea, C. enodis, and C. fjellbergi and another includes C. kutchin, C. parvulus, and C. thienemanni. The decision whether or not these 6 species should be retained in Ceratozetessensu stricto awaits discovery of their immatures and molecular analysis.

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.

The hemlock looper, Lambdina fiscellaria, is one of the most economically damaging defoliators of North American coniferous forests. Basic information on its reproductive biology is an essential prerequisite for understanding its population dynamics. Realized fecundity for the two major hemlock looper ecotypes varies along a latitudinal gradient in eastern Canada, but their daily oviposition patterns are similar. Mated females lay eggs after a short pre-oviposition period, with daily oviposition peaking in the first 3 days. Mated females lay significantly more eggs than unmated ones, the latter laying their eggs more evenly throughout their life. Eggs deposited early in the oviposition period are larger than those deposited near the end. This may influence over-winter survival of hemlock loopers and should be considered in studies to better understand the population dynamics and improve management of this defoliator.