We identified females of six species of leafhoppers (tribe Empoascini), Asymmetrasca decedens (Paoli), Empoasca affinis Nast, E. decipiens Paoli, E. pteridis (Dahlbom), E. vitis Göthe, and Jacobiasca lybica (Bergevin and Zanon), using morphological characters of the ovipositor and isozyme and mitochondrial COI sequence analyses. Useful traits of the ovipositor are tooth morphology, length of the toothed area, form of sculpturing, and number and position of sensilla on the first and second pair of valves. Among the set of enzyme systems assayed, four putative loci, sod, hk-2, est-3, and est-2, together provided reliable diagnostic characters for single species, pairs of species, and groups of species. Analysis of mtCOI sequences revealed differences between the six species of Empoascini, and the neighbour-joining tree separated them into three distinct groups. Phenetic trees elaborated using Nei’s index and the Kimura two-parameter model clustered the six Empoascini species in similar groups.

Two full-length cDNA sequences encoding digestive serine proteases (designated as SmPROT-1 and SmPROT-2) were recovered from the midgut of the orange wheat blossom midge, Sitodiplosis mosellana (Géhin) (Diptera: Cecidomyiidae), in an ongoing expressed sequence tag project. The deduced amino acid sequences shared homology with digestive serine proteases from insect and non-insect species, including conserved regions such as the catalytic triad, active pocket, and conserved structural motifs. Secretory signal peptides in both proteases at the N-terminals indicate that these proteins could function as midgut digestive serine proteases. A phylogenetic analysis grouped SmPROT-1 and SmPROT-2 with trypsin-like and chymotrysin-like serine proteases, respectively. Quantitative real-time PCR analysis showed that SmPROT-1 and SmPROT-2 were expressed predominantly in the midgut rather than in other tissues (fat body and salivary glands). Expression analyses revealed high mRNA levels for the feeding instars (1st- and 2nd-instar larvae) compared with other stages (neonate, 3rd instar, pupa, and adult). These results provide new insights into the biology of S. mosellana and are discussed in the context of developing alternative control strategies.

Gypsy moth, Lymantria dispar (L.) (Lepidoptera: Lymantriidae), multicapsid nucleopolyhedrovirus (LdMNPV) has been registered as a microbial pest-control product in the United States (Gypchek®) and Canada (Disparvirus®). Similarly, Douglas-fir tussock moth, Orgyia pseudotsugata (McDunnough) (Lepidoptera: Lymantriidae), multicapsid nucleopolyhedrovirus (OpMNPV) is registered in the United States and Canada as TM BioControl-1® and a product derived from TM BioControl-1 (Virtuss®) is also registered in Canada. To determine changes that may have occurred in these products over time, we compared DNA from Gypchek with Disparvirus and DNA from TM BioControl-1 with Virtuss using restriction fragment length polymorphism (RFLP) analysis. Gypchek and Disparvirus showed the same RFLP banding patterns when viral genomic DNA was digested with BamH I, EcoR V, and Hind III and only a single band difference at approximately 1.6 kilobase (kb) when digested with Bgl II. TM BioControl-1 and Virtuss showed no differences in genomic DNA when digested with Bgl II, Sam I or Hind III. Twelve viral open reading frames (ORFs) were amplified from Gypchek and Disparvirus and nine from TM BioControl-1 and Virtuss by polymerase chain reactions (PCR). The amplified ORFs ranged from highly conserved (polyhedrin) to least conserved (vp91 capsid associated protein). The products were sequenced and the deduced protein products compared. Amino acid sequences deduced from the sequenced PCR products indicated that 8 of the 12 proteins were identical in the two LdMNPV products. The four proteins showing minor sequence variations were DNA polymerase, LEF-8, P74 envelope protein, and VP 91 capsid associated protein. No differences were detected in the protein products deduced from the nine sequenced ORFs from TM BioControl-1 and Virtuss. Comparative RFLP and protein phylogenetic analyses of Gypchek with Disparvirus and TM BioControl-1 with Virtuss revealed little difference between the respective LdMNPV and OpMNPV populations that make up these product pairs.

The mountain pine beetle, Dendroctonus ponderosae Hopkins (Coleoptera: Curculionidae), is a destructive insect pest in western Nearctic conifer forests. Currently, British Columbia, Canada, is experiencing the largest recorded outbreak of this insect, including areas that historically have had low climatic suitability for it. We analyzed 26 constitutive resin terpenes in phloem samples from British Columbia lodgepole pine (Pinus contorta) populations to test for differential resistance to mountain pine beetle attack, based upon the likelihood of previous exposure to mountain pine beetle. We assessed sampled trees for number of mountain pine beetle attacks, number of pupal chambers, and tree survival the following spring. Significant differences were found when levels of certain terpenes in lodgepole pine populations that had likely experienced substantial mountain pine beetle infestations in the past were compared with those in populations that likely had not experienced large outbreaks of mountain pine beetle. Although we expected southern pine populations to contain more total terpenes than northern populations, owing to higher historical exposure to the beetle, the converse was found. Northern populations generally had higher levels of constitutive terpenes and beetle attack than southern populations. Because several terpenes are kairomones to the mountain pine beetle and also serve as precursors for the synthesis of pheromones, the lower levels of terpenes expressed by lodgepole pines from the historical range of the mountain pine beetle may render them less chemically perceptible to foraging beetles.

Wheat, Triticum L. (Poaceae), varieties with deterrence to oviposition by the wheat midge, Sitodiplosis mosellana (Géhin) (Diptera: Cecidomyiidae), can be useful in reducing seed damage. The behaviour of ovipositing females on spring wheat, T. aestivum L., with and without oviposition deterrence was investigated to account for observed differences in oviposition on deterrent and nondeterrent hosts. On deterrent wheat, 34% of females landing oviposited compared with 100% of females landing on nondeterrent wheat. The sequence of female behaviours just prior to egg-laying on deterrent spikes was similar to that on nondeterrent spikes. The length of time required to lay an egg and mean egg-batch size were similar on deterrent and nondeterrent wheat, but females spent nearly twice as long on the latter. After landing on deterrent wheat, females took longer to begin ovipositing and longer to leave after the last oviposition event than did females on nondeterrent wheat, which further reduced the time available for oviposition on deterrent compared with nondeterrent wheat. As a result of these behavioural differences, deterrence reduced oviposition by more than 60%.

Western honey bees, Apis mellifera L. (Hymenoptera: Apidae), occur in nearly every region inhabited by man because they provide valuable honey, wax, and pollination services. Many commercial honey bee operations are plagued by economically important parasites; however, beekeepers on the island of Newfoundland, Canada, are in a unique position because of the province of Newfoundland and Labrador’s strict import regulations and geographic isolation. We surveyed about 25% of the island’s approximately 100 managed honey bee colonies. The parasitic mites Varroa destructor Anderson and Trueman (Acari: Varroidae) and Acarapis woodi (Rennie) (Acari: Tarsonemidae) were not detected, whereas Nosema spp. microsporidia were detected in two of four beekeeping operations and in 11 of 23 (48%) colonies (intensity = 482 609 ± 1199 489 (mean ± SD); median intensity = 0). Because V. destructor and A. woodi are important pests that typically require chemical treatments, beekeepers on the island of Newfoundland may be uniquely positioned to market organic honey bee products from colonies that could also be a source of mite-naïve bees for research.

Carabid beetles can escape from pitfall traps. To determine whether or not a female-biased sex ratio for catches of Carabus lewisianus Breuning from pitfall traps could be explained by sexual differences in the rates of capture by and escape from traps, we performed two laboratory experiments to estimate these rates using mathematical models. The results indicated that the two sexes dropped into the pitfall traps at almost equal rates (0.0456/min for females and 0.0366/min for males) and that males escaped from the traps at rates of 0.0591 and 0.0889/min, but no females managed to escape. The bias of escape rates in the field is shown by the higher captures of female C. lewisianus by pitfall traps. Calibration of capture and escape rates suggested similar activity densities of the two sexes in the field. Development of more accurate measures of the number of the relevant sex on the soil surface, and of the methodology for estimating the values of parameters in the field is discussed.

In 2008 we compared numbers of emerald ash borer, Agrilus planipennis Fairmaire, captured on glue-coated prism traps of different sizes (standard, double-length narrow, and quarter), colors (green and purple), and height in relation to the canopy of ash host trees (midcanopy (10–13 m) and ground level (1.5 m)). Standard-size prism traps caught more A. planipennis than did quarter-size prism traps, but catch per square metre of surface area did not differ significantly among the three trap sizes. Twenty percent of quarter-size prism traps failed to catch a single beetle, while all traps of the two larger sizes were successful. The larger traps therefore appear to be more useful as detection tools. In 2009 we compared purple and green standard-size prism traps at three heights: midcanopy (13 m), lower canopy (6 m), and ground (1.5 m). Green traps caught more adult emerald ash borers than did purple traps in the mid and lower canopy, but there was no difference between traps hung at 1.5 m. The ratio of male to female adult emerald ash borers was also higher on green than on purple traps at all three heights.

The question “why sex?” is a longstanding fundamental puzzle in biology. Although there may be several answers, no satisfactory theory has emerged. We present an argument in favour of one function of sex, derived from a study of the population genetics and ecology of the cabbage butterfly, Pieris rapae (L.) (Lepidoptera: Pieridae), on three continents between 1984 and 2009, and from previously published studies of other organisms. We provide evidence that responsiveness to directional selection (RDS), a measure related to “narrow-sense heritability”, can be dramatically reduced by truncation selection in a single generation and rapidly restored within a few generations. Viewing a population as a collection of sexual families, we show that rapid restoration of RDS after truncation selection is essential to maintain population variance. The only known mechanism that will rapidly restore RDS is sexual recombination. We therefore conclude that in P. rapae, sex restores the genetic variation that a population needs to match unpredictable environmental variation, despite selection tending to reduce that genetic variation.