We describe the calling posture of the brown spruce longhorn beetle, Tetropium fuscum (F.), and demonstrate, using solid-phase micro-extraction and gas chromatography – mass spectrometry, that this posture is positively correlated with the release of fuscumol, a male-produced long-range pheromone. The posture is observed only in males and is characterized by an extension of the legs that raises the body entirely off the substrate at an angle of approximately 10°, with the posterior end higher than the head. Characterization of the calling posture is a useful diagnostic tool for future research on the reproductive biology of T. fuscum, since a simple visual assessment can be used instead of chemical analysis to determine when males are emitting fuscumol. In addition, we demonstrate that the presence of conspecific males stimulates calling behaviour in T. fuscum. This study contributes much-needed data on the biology and mating behavior of this invasive wood-boring species.

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.

The discovery in southwestern British Columbia of widespread established populations of the Palaearctic leafminer Heterarthrus vagans (Fallén) feeding on native red alder, Alnus rubra Bong. (Betulaceae), is reported. A preliminary survey suggests that it is currently confined to the Fraser Valley west of Hope, its distribution extending north along Howe Sound almost to Squamish. It was not found in the greater Victoria area. No other regions of the province have been surveyed. This introduced sawfly completes at least two generations a year. Diagnostic characters to aid the recognition of adults and feeding larvae of H. vagans and a modified key to adult Heterarthrinae on Betulaceae are provided.

Soybean oil (SO) is considered an active ingredient in commercial BiteBlocker™ insect-repellent products. Our objective was to test mechanisms by which SO exhibits repellency, using the yellow fever mosquito, Aedes aegypti (L.) (Diptera: Culicidae), as a representative blood-feeding insect. In dual-port glass-cage olfactometers, human hands treated with SO at various concentrations attracted as many mosquitoes as did untreated hands, indicating that SO has no long-range repellent effect. In contrast, hands treated with N,N-diethyl-3-methylbenzamide (DEET) attracted significantly fewer mosquitoes than did untreated control hands. In cage experiments, treating an area of a human forearm exposed to A. aegypti with SO provided no protection against bites, whereas treating it with DEET did. These results indicate that SO has no short-range or contact repellent properties. Both DEET and the BiteBlocker™ product conferred protection for periods similar to those previously reported. Based on our data, classification of SO as an active mosquito repellent should be reconsidered.

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.

Western boxelder bugs, Boisea rubrolineata (Barber), form large aggregations on pistillate boxelder, Acer negundo L. (Aceraceae), host trees with maturing seeds, and cluster on warm, sunlit surfaces prior to overwintering. We have recently shown that B. rubrolineata is attracted to the host-tree semiochemicals phenylacetonitrile and 2-phenethyl acetate. We report results of chemical analyses and laboratory bioassays suggesting that aggregation and sexual communication in B. rubrolineata are mediated by 2-phenylethanol. This compound serves as an aggregation pheromone for females, males, and 5th-instar nymphs in midsummer, and in males it appears to serve as a sex-attractant pheromone in early spring. As an aggregation pheromone, 2-phenylethanol originates from the feces of seed-feeding females and males and (or) the ventral abdominal gland of males. As a sex-attractant pheromone, it originates from the ventral abdominal gland of males that emerge from overwintering diapause. Aggregations of B. rubrolineata in the fall and winter are mediated by other as yet unknown pheromones.

Tests were performed to determine whether combining two thrips lures, ethyl nicotinate (EN) and ethyl isonicotinate (EI), in the same water trap increased the numbers of New Zealand flower thrips (NZFT), Thrips obscuratus Crawford, and onion thrips, T. tabaci Lindeman (Thysanoptera: Terebrantia: Thripidae), caught in the field relative to traps with a single lure. Traps with both lures (1:1 ratio; mixture or separate adjacent vials) caught 5–9 times more female onion thrips (thelyotokous populations are the most prevalent in New Zealand) than traps with EN only (P<0.001), but in similar numbers to traps with EI only. Traps with both lures caught 2–3 times as many male and female NZFT than traps with EI only, but in similar numbers to traps with EN only. Thus, a combination of the two lures in one trap could be used to detect and monitor flying onion thrips and NZFT simultaneously.

A white spruce, Picea glauca (Moench) Voss (Pinaceae), plantation in southern Quebec was found to contain two distinct types of trees, the first resistant and the second susceptible to attack by spruce budworm, Choristoneura fumiferana (Clemens) (Lepidoptera: Tortricidae). To identify the mechanisms of white spruce resistance to spruce budworm, we studied the role of epicuticular waxes, comparing (i) the foliar chemistry of susceptible and resistant trees and (ii) the feeding pattern of larvae at first contact with the foliage. Needles collected from resistant trees contained concentrations of the monoterpenes α-pinene and myrcene that were 307% and 476%, respectively, above those found in needles collected from susceptible trees. Although there were no significant differences in probing behaviour, significantly fewer larvae transitioned from probing to feeding on resistant needles; this led to fewer feeding bouts as well as a significantly shorter first meal. Removal of waxes increased the number of individuals transitioning from probing to feeding on resistant needles; this led to more feeding bouts. Our results demonstrate that monoterpenes influence the pattern of feeding of spruce budworm larvae as well as playing an important role in white spruce resistance.

The triterpenoid saponins soyasaponin I, dehydrosoyasaponin I, echinocystic acid 3-glucoside, β-escin, glycyrrhizic acid, hederacoside C, and α-hederin were tested alone and in combination with insecticidal PA1b peptide mixtures isolated from peas for their effects on the feeding and survival of a stored-product insect, the rice weevil, Sitophilus oryzae (L.). There were two sources of peptides: a purified extract composed primarily of PA1b peptides and a partially purified extract (C8 extract) that contained mainly peptides and lesser amounts of soyasaponin I, dehydrosoyasaponin I, and other compounds. Dehydrosoyasaponin I, echinocystic acid 3-glucoside, α-hederin, and β-escin were active (causing reduced feeding and increased mortality) when used alone. Soyasaponin I, hederacoside C, and glycyrrhizic acid were inactive when used alone. Purified peptides and C8 extract were active when used alone. The mixtures of the inactive soyasaponin I and the active peptides were as active as peptides alone, even when peptides composed only 10% of the mixture. Similar trends were seen with the mixtures of β-escin and PA1b. In general, the mixtures of saponins and peptides were synergistic. Possible modes of synergistic action are discussed.

Surveys for signs of attack by Asian long-horned beetles, Anoplophora glabripennis (Motschulsky) (Coleoptera: Cerambycidae), currently rely upon visual examination of trees to discover signs of attack. By embedding simulated A. glabripennis oviposition pits and exit holes on open-grown Norway maples, Acer platanoides L. (Aceraceae), we evaluated the effect of sign density, height (below or above 2.5m), and position (bole or branch) when foliage was present or absent on inspector ability to distinguish trees with or without signs. From this, we quantified detectability, or the proportion of trees correctly identified as infested, and determined the time taken to do so. Effectiveness in detecting trees with signs improved when sign density increased, when signs were below 2.5m, and when oviposition pits were located on boles and exit holes on branches. These main findings require some caveats, due to a number of significant interactions. Foliage presence/absence had no apparent influence on effectiveness; possible reasons are provided for this result. Time-to-find curves, which illustrated the proportion of inspectors who accurately identified an infested tree as a function of survey duration, revealed that for most treatment combinations, most infested trees were detected within the first 2 min of survey time. These findings provide baseline data to assist managers in designing effective protocols for ground surveys of A. glabripennis.

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.

Monitoring of pear psylla (Cacopsylla pyricola (Förster), Hemiptera: Psyllidae) prior to spring bud break could aid in predicting the size of subsequent spring populations and lead to improved proactive management decisions. Yellow traps are commonly used to monitor hemipteran pests including pear psylla, but very little is known regarding seasonal changes in attractiveness of yellow traps or relative attractiveness of colours other than yellow. This study presents seasonal colour-trap preferences of pear psyllas based on pear (Pyrus communis L., Rosaceae) phenological stages in the mid-Atlantic region of the United States of America. Black, blue, brown, clear (colourless), green, orange, red, white, and yellow traps were assayed against wild adult psylla populations over a 2-year period. Pear psyllas had a strong preference for yellow and orange when green leaves were present; however, we found no statistically significant difference between traps of different colours prior to spring bud break. Significantly more female psyllas were caught overall, but there was no gender-based colour bias. None of our colour traps caught significantly fewer psyllas than did clear (background hue) traps, suggesting that no traps were repellent.

Honey bees, Apis mellifera (L.) (Hymenoptera: Apidae), are parasitized by the microsporidians Nosema apis (Zander) and Nosema ceranae (Fries). Molecular techniques are commonly used to differentiate between these parasites because light microscopy is inadequate. Our objectives were to (i) adapt the previously published duplex polymerase chain reaction (PCR) targeting the 16S rRNA gene of N. apis (321APIS-FOR, 321APIS-REV) and N. ceranae (218MITOC-FOR, 218MITOC-REV) using qualitative real-time PCR assay with SYBR® Green I dye (R-T PCR) and DNA melting-curve analysis, and (ii) determine whether the two Nosema species can be detected simultaneously in honey bees. Total spore counts and purified total genomic DNA were obtained from 37 bee samples (19 individual workers and 18 pooled samples of 15 workers) collected in Nova Scotia, Prince Edward Island, and Newfoundland, Canada. Overall, the prevalence of Nosema species was 86.5% (32/37 samples of bee DNA), based on conventional PCR and the optimized R-T PCR assay. The melting-curve analysis showed three groups of curve profiles that could determine the prevalence of N. apis, N. ceranae, and co-infection (21.9%, 56.2%, and 21.9%, respectively). The duplex R-T PCR assay was efficient, specific, and more sensitive than duplex conventional PCR because co-infection was identified in 5.4% (n = 2) more samples. Sequencing of R-T PCR products confirmed the results of the melting-curve analysis. Duplex R-T PCR with melting-curve analysis is a sensitive and rapid method of detecting N. apis, N. ceranae, and co-infection in honey bees.

The plum curculio, Conotrachelus nenuphar (Herbst), is a serious pest of stone and pome fruits (Rosaceae) in eastern North America. We recorded captures of adult plum curculios in the field and measured electroantennogram (EAG) activity in the laboratory associated with cultivars of four hosts, ‘Formosa’ Japanese plum (Prunus salicina Lindl.), ‘Stanley’ European plum (P. domestica L.), ‘Empire’ apple (Malus domestica Borkh.), and ‘Loring’ peach (P. persica (L.) Batsch) (Rosaceae) to determine whether hosts that may be attractive to the plum curculio under field conditions also elicit positive EAG responses. Trap captures of adults on ‘Formosa’ plum were significantly greater than on any other host, and corresponding headspace extracts also produced strong EAG responses throughout the active season. ‘Stanley’ plum and ‘Loring’ peach, the other stone-fruit hosts included in the study, elicited strong EAG responses throughout the season, although trap captures associated with these hosts were generally not as high as for ‘Formosa’ plum. Throughout the season, trap captures of adults were significantly lower for ‘Empire’ apple than for ‘Formosa’ plum, and EAG responses were much lower than for all stone-fruit hosts. Our results indicate that volatiles from ‘Formosa’ plum likely contain uniquecompounds or are comprised of ratios of stimulating compounds that make it much more attractive to plum curculio in the field.