Search

More than 1180 non-native species, mostly of Palaearctic origin, have been recorded from the boreal zone of Canada, with the highest diversity on the island of Newfoundland and in the southern boreal zone of Ontario and Quebec. The non-native biota of the boreal zone (and of Canada in general) is poorly known in terms of species composition and distribution. A large proportion of species are associated with disturbed anthropogenic habitats such as urban areas, agricultural landscapes, transportation and communication corridors, and industrial developments. Natural habitats in the boreal zone have a high degree of resistance to invasion compared with those of other Canadian zones, likely owing to harsh climates, low light levels, poor soil nutrient availability, low soil pH, low productivity, and dense covering of the ground by plants, especially bryophytes. Of the relatively few non-native species that have successfully colonized the boreal zone, many decline greatly in abundance after a few years, suggesting biotic resilience. To date the boreal zone has shown the least resistance and resilience to large vertebrates (moose and white-tailed deer) translocated to islands, diseases of vertebrates, and earthworms. In general, the ecological impacts of non-native species on the boreal zone have been poorly studied, and there are few examples where such impacts are evident. Likewise, there has been little attempt to quantify the economic impacts of non-native species in either the boreal zone or in Canada as a whole. In the few cases where management measures have been implemented for highly destructive non-native species, results have been somewhat successful, especially where classical biological control measures have been implemented against insects on trees. Chemical and mechanical management measures have had only limited success in localized situations. Management resources are most effectively applied to reducing the risk of introduction. The risk to the boreal zone posed by future new non-native species is increasing with the warming climate and the fast and direct transport of goods into the boreal zone from points of origin. Five recommendations are provided to address recognized gaps concerning non-native species. Key words: boreal, non-native species, ecological impacts, risk, biological invasion. On a enregistre plus de 1180 especes non indigenes, surtout d'origine palearctique, dans la zone de la foret boreale du Canada, dont la plus grande diversite se retrouve sur l'ile de Terre-Neuve et dans la zone boreale meridionale de l'Ontario et du Quebec. Le biote non indigene de la zone boreale (et du Canada en general) est mal connu en ce qui concerne sa composition et sa distribution. Une forte proportion des especes est associee a des habitats perturbes par l'homme comme les milieux urbains, les paysages agricoles, les corridors de communication et de transport ainsi que les developpements industriels. Les habitats naturels de la zone boreale montrent un fort degre de resistance a l'invasion, comparativement a ceux d'autres zones du Canada, vraisemblablement a cause des climats rigoureux, des faibles degres d'illumination, de la faible disponibilite des nutriments du sol, du faible pH des sols, de la faible productivite, et de la dense couverture du sol par les plantes, surtout les bryophytes. Parmi les peu nombreuses especes ayant colonise avec succes la zone boreale, plusieurs connaissent un fort declin en abondance apres quelques annees suggerant une resilience biotique. A date, la zone boreale a montre les moindres resistances et resiliences chez les grands vertebres (orignaux et cerf de Virginie) transferes sur ces iles, les maladies des vertebres et les vers de terre. En general, on a peu etudie les impacts ecologiques des especes non indigenes de la zone boreale et il y a peu d'exemples oU ces impacts sont evidents. De meme, il y a eu peu de tentatives pour quantifier les impacts economiques des especes non indigenes, que ce soit en zone boreale ou au Canada en general. Dans les rares cas oU des mesures d'amenagement ont ete mises en place pour les especes non indigenes fortement destructives, les resultats ont eu assez de succes, surtout la oU les mesures de maitrise biologique classique ont ete utilisees contre les insectes et les arbres. Les mesures chimiques et mecaniques n'ont qu'un succes limite dans des situations localisees. Les ressources de l'amenagement sont plus efficaces lorsqu'elles sont appliquees pour reduire le risque d'introduction. Le risque pour la foret boreale pose par de futures especes non indigenes augmente avec le rechauffement climatique et le transport rapide et direct de marchandises dans la zone boreale, a partir de leurs points d'origine. Les auteurs font cinq recommandations pour prendre en compte les lacunes reconnues au sujet des especes non indigenes. [Traduit par la Redaction] Mots-cles: boreal, especes non indigenes, impacts ecologiques, risque, invasion biologique., 1. Introduction Since the Wisconsinan glacial maximum ~21400 years ago, the rate of change of species composition in Canada has been determined by natural processes such as the rate and [...]

The emerald ash borer (EAB), Agrilus planipennis Fairmaire (Coleoptera: Buprestidae), is a highly destructive primary pest of ash (Fraxinus sp., Oleaceae) trees outside of its native range. Ash is an important component of many ecosystems and its loss would be detrimental to both the economy and the environment. The present study aimed to improve our understanding of the effectiveness of green sticky prism traps baited with host kairomone and insect pheromone lures for A. planipennis and to collect data for modelling the range of attraction of the pheromone (3Z)‐dodecen‐12‐olide [(3Z)‐lactone]. Traps were deployed over a single flight season in urban locations of Ontario, Canada, with low densities of EAB. Traps were placed in pairs of trees separated by not more than 25 m. All traps contained the host kairomone, (3Z)‐hexenol, with the remaining half in each pairing additionally baited with (3Z)‐lactone pheromone. Both lure types were highly effective in capturing EAB, with >90% detection rates overall. However, traps baited with the lactone pheromone and host volatile lures doubled trap captures of EAB over distances of at least 25 m from the nearest traps baited with only host volatiles. Although the baseline detection rate of traps containing (3Z)‐hexenol alone is not significantly reduced compared with traps containing (3Z)‐lactone, the overall trap effectiveness is significantly increased when (3Z)‐lactone is present. The implications for the use of (3Z)‐lactone at 3 mg per septum dose in an early warning trapping system are discussed. Trap layout methods and risk‐based analysis models can now be further refined by including these data about the attractive range of lures and their behaviour in different plot environments. [ABSTRACT FROM AUTHOR]

Emerald ash borer (EAB), Agrilus planipennis Fairmaire, is an invasive pest causing extreme levels of mortality in ash (Fraxinus spp., Oleaceae) in the USA and Canada. Knowledge of buprestid chemical ecology is sparse, but the appearance of EAB in North America and its devastating ecological and economic impacts have afforded an opportunity to study its semiochemistry and biology in detail. We review the chemical ecology of EAB and the application of its sex pheromone, the female-produced (3 Z)-dodecen-12-olide ((3 Z)-lactone), and the green leaf volatile, (3Z)-hexenol, in operational surveys and experimental control strategies. Adding (3 Z)-lactone to green sticky prism traps with (3 Z)-hexenol on the south aspect of the tree canopy consistently increases trap captures and detection rates at low insect densities. This bait combination is more attractive than (3 Z)-hexenol alone, especially when traps are in a competitive deployment. Using a 'push–pull' strategy, some nonhost volatiles deployed in ash trees significantly lower trap capture and may be useful in the push component, with a girdled tree treated with systemic insecticide constituting the pull component. We review reliable branch sampling techniques to estimate incidence and density of EAB which positively correlate with trap capture. We recommend using these combined tools to detect, delimit, and monitor EAB. [ABSTRACT FROM AUTHOR]

We develop an acceptance sampling approach for surveillance of the emerald ash borer (EAB), a harmful forest pest, in Winnipeg, Canada. We compare sampling strategies computed with two different management objectives. The first objective maximizes the expected area with detected infestations and the second objective minimizes the expected number of undetected infested trees in sites that were not inspected or where inspection did not find an infestation. The choice of the management objective influences the survey strategy: achieving the first objective involves selecting sites with high infestation rates proximal to the infested area, whereas the second objective requires inspecting sites with both high infestation rates and high host densities. Adding uncertainty prescribes inspecting a larger area with lower sampling rates and extending the surveys to farther distances from the infested locations. If a decision maker wants to minimize the worst-case damage from failed detections, the optimal strategy is to survey more sites with high host densities at farther distances, where EAB arrivals could cause significant damage if not detected quickly. Accounting for the uncertainty addresses possible variation in infestation rates and helps develop a more diversified survey strategy. The approach is generalizable and can support survey programmes for new pest incursions. [ABSTRACT FROM AUTHOR]

The bronze birch borer, Agrilus anxius , is a North American buprestid pest of stressed or weakened birch trees (Betula spp.) and is considered a major threat to European birch species as a potentially adventive insect. Laboratory bioassays and field trapping experiments were conducted to elucidate potential visual and chemical cues used in host location in this species. Birch bark and foliar volatiles (Betula papyrifera Marsh) and a pheromone attractive to the congener, A. planipennis , (3 Z)-dodecen-12-olide ((3 Z)-lactone), were tested along with a girdled tree treatment, with purple sticky prism traps. Only the girdled tree treatment with purple traps elicited significant attraction by adult A. anxius. Various colours of sticky traps were tested with host volatiles attractive to A. planipennis ; results showed that unbaited green sticky traps were more attractive than other colours tested; none of the host volatiles tested increased trap capture with any traps. Examination of foliage and bark of B. papyrifera by GC/EAD, and GC/MS techniques has identified several EAD-active compounds with (3 Z)-hexenol and (5 S ,7 S)-conophthorin as the most EAD-active molecules. Neither compound, however, alone or combined, elicited significant trap capture on green sticky prism traps; these compounds may find importance as synergists once the pheromone for A. anxius is identified. [ABSTRACT FROM AUTHOR]

Recent research has demonstrated that the emerald ash borer, Agrilus planipennis Fairmaire (Coleoptera: Buprestidae), uses visual and chemical cues when locating potential mates and host trees. Here, we present the first evidence of the production of possible acoustic cues generated by adult males and females. We demonstrate for the first time that simultaneous wing opening and head 'pumping' in both males and females produce specific and distinct sounds. Acoustic recordings demonstrate that these sounds consist of a phrase comprising a 'click' generated by wing opening, followed by two separate chirps corresponding to the outward and subsequent inward movement of the head. Mean primary and secondary chirp durations were 0.332 ± 0.038 and 0.414 ± 0.046 s for males and 0.414 ± 0.046 and 0.389 ± 0.032 s for females, respectively. Overall mean phrase durations were 0.905 ± 0.114 s in males and 1.133 ± 0.133 s in females. Mean maximum phrase frequencies were 8 706.1 ± 141.1 and 7 885.0 ± 499.2 Hz in males and females, respectively. There were no significant differences in sound parameters between males and females. To determine whether these events were related to mating pair formation, we observed the occurrence of these events in adults paired with either another male or female and lone adults, and observed the number of mating pairs in copula formed during or shortly after sound production by either of the mating party. The mean number of sound‐generating events per min was significantly greater in males paired with females (0.75 ± 0.15) and/or other males (0.55 ± 0.23) vs. unpaired males (0.14 ± 0.06). Conversely, the mean number of sound‐producing events for lone females (1.4 ± 0.2) was significantly greater than for females paired with either males (0.49 ± 0.18) or other females (0.38 ± 0.10). No mating pairs in copula were formed during any of our observations. Scanning electron microscopy images showed the presence of possible pars stridens and plectrum structures on the ventral surfaces of the gula and pronotum in both males and females. Furthermore, we observed that the proportion of males and females exhibiting these specific behaviors were significantly greater under both halogen and incandescent light than under darkness, signifying the importance of light source or type on the production of acoustic signals. Although we did not find evidence of these behaviors being related to the courtship sequence, our results indicate the presence of a previously undescribed sound‐generation behavior in A. planipennis that is significantly influenced by light conditions. A trap that utilizes attractive plant and pheromone volatiles to detect emerald ash borer (EAB) (Coleoptera: Buprestidae) adults is the principal method for monitoring EAB populations. This trap exploits visual and chemical cues used by EAB adults to locate host trees and one another. An additional, yet undescribed, sensory modality in EAB is the role of acoustic cues produced by adults. We describe for the first time the existence of quantifiable and detectable acoustic sounds generated by EAB adults. [ABSTRACT FROM AUTHOR]

Copyright of Canadian Entomologist is the property of Cambridge University Press and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Woodborers in the Agrilus genus ( Coleoptera: Buprestidae) pose high invasiveness risk as indicated by the recent invasion and continental spread of emerald ash borer, and the associated threat to ash resources in North America. In that context, development of detection tools for potentially invasive Agrilus spp. is a research priority. Experiments carried out in 2013 in Slovakian beech and poplar forests evaluated the attraction of multiple Agrilus species to green and purple sticky prism traps baited with various lures [blank, cubeb oil, ( Z)-3-hexenol]. The two most abundant species were Agrilus viridis L. in beech ( Fagus spp.) forest (146 adults, >95% of which were females) and Agrilus convexicollis Redtenbacher in poplar ( Populus spp.) forest (158 adults, two-thirds of them males). The two species exhibited opposite responses to color: purple traps attracted 2-3× more adult A. viridis than green traps, whereas most (>95%) specimens of A. convexicollis were captured on green traps. Volatile baits did not influence captures of adults for either species. The introduction and establishment of A. viridis in North America is of particular concern owing to its feeding niche (primary pest that can attack healthy trees), large body size, and high level of polyphagy (>10 genera of host trees). Additional experiments conducted in beech forests in 2014 found purple prism traps more attractive to female A. viridis than green prism traps, especially those baited with cubeb oil. No analysis was conducted for males because of their low abundance. Female A. viridis flew earlier in 2013 than in 2014, but neither their body size nor fecundity varied between years. In both years, large females had more eggs in their abdomen than small females, and the number of eggs steadily declined over time, which suggests that female A. viridis are reproductively mature at emergence. [ABSTRACT FROM AUTHOR]

Agrilus planipennis (Coleoptera: Buprestidae), is causing extensive mortality of ash (Fraxinus Linnaeus; Oleaceae) in North America. Once detected in an area, resource managers require methods to obtain estimates that could improve management decisions. We studied the within-crown and within-branch distribution and abundance of A. planipennis feeding galleries by sampling 3-m-long branches from asymptomatic urban ash trees and subdividing each branch into 12 sections of 25 cm each. We found galleries in all 12 sections of some, but not all, branches. Section was a significant source of variation in A. planipennis gallery density/m² of branch surface area. A comparison of predictive power and efficiency of estimates for samples of increasing length, and for samples of the same length but consisting of different combinations of sections, revealed that those based on the two basal 25-cm sections of a branch from the lower-crown or mid-crown of an asymptomatic tree were less accurate and precise than those based on more sections, but were the most cost effective. Whittling more sections per branch, irrespective of the combinations of branch sections per length, improved predictive power but reduced cost effectiveness. We also observed that crown level was not important, and aspect was only marginally so, when estimating gallery abundance per sampled branch. [ABSTRACT FROM AUTHOR]