Can. Ent. 115: 2 9 S 3 0 2 (1983) The multiple funnel trap, an efficient, collapsible, non-sticky trap for scolytid beetles, consists of a series of vertically aligned funnels with a collecting jar at the bottom. The trap compared favorably with sticky traps and Scandinavian drainpipe traps for three species of ambrosia beetles and the mountain pine beetle. Minimum maintenance required for this trap allows for high efficiency in pheromone-based research, survey, and mass trapping of scolytid beetles.

Summary 1.Hosts may evolve defences that make them less susceptible and suitable to herbivores impacting their fitness. Due to climate change-driven range expansion, herbivores are encountering naı¨ve host populations with increasing frequency. 2. Aggressive bark beetles are among the most important agents of disturbance in coniferous forest ecosystems. The presence of bark beetle outbreaks in areas with a historically unsuitable climate, in part a consequence of climate change, provided an opportunity to assess the hypothesis that the mountain pine beetle Dendroctonus ponderosae has higher reproductive success in lodgepole pine Pinus contorta trees growing in areas that have not previously experienced frequent outbreaks. 3. We felled and sampled mountain pine beetle-killed trees from historically climatically suitable and unsuitable areas, i.e. areas with and without a historical probability of frequent outbreaks. Reproductive success was determined from a total of 166 trees from 14 stands. 4. Brood productivity was significantly affected by climatic suitability class, such that mean brood production per female increased as historical climatic suitability decreased. 5. Synthesis and applications. The current study demonstrates that the mountain pine beetle has higher reproductive success in areas where its host trees have not experienced frequent beetle epidemics, which includes much of the current outbreak area in north central British Columbia. This increased productivity of mountain pine beetle is likely to have been a key reason for the rapid population buildup that resulted in unprecedented host tree mortality over huge areas in western Canada. The outbreak thus provides an example of how climate change-driven range expansion of native forest insects can have potentially disastrous consequences. Since an increased reproductive success is likely to accelerate the progression of outbreaks, it is particularly critical to manage forests for the maintenance of a mosaic of species and age classes at the landscape level in areas where host tree populations are naı¨ve to eruptive herbivores.

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Environmental change has a wide range of ecological consequences, including species extinction and range expansion. Many studies have shown that insect species respond rapidly to climatic change. A mountain pine beetle epidemic of record size in North America has led to unprecedented mortality of lodgepole pine, and a significant range expansion to the northeast of its historic range. Our goal was to determine the spatial genetic variation found among outbreak population from which genetic structure, and dispersal patterns may be inferred. Beetles from 49 sampling locations throughout the outbreak area in western Canada were analysed at 13 microsatellite loci. We found significant north-south population structure as evidenced by: (i) Bayesian-based analyses, (ii) north-south genetic relationships and diversity gradients; and (iii) a lack of isolation-by-distance in the northernmost cluster. The north-south structure is proposed to have arisen from the processes of postglacial colonization as well as recent climate-driven changes in population dynamics. Our data support the hypothesis of multiple sources of origin for the outbreak and point to the need for population specific information to improve our understanding and management of outbreaks. The recent range expansion across the Rocky Mountains into the jack/lodgepole hybrid and pure jack pine zones of northern Alberta is consistent with a northern British Columbia origin. We detected no loss of genetic variability in these populations, indicating that the evolutionary potential of mountain pine beetle to adapt has not been reduced by founder events. This study illustrates a rapid range-wide response to the removal of climatic constraints, and the potential for range expansion of a regional population.

An outbreak of the mountain pine beetle (Dendroctonus ponderosae Hopk.) in central British Columbia, Canada, has reached an unprecedented size and intensity and has been spreading. The 2005 emergence and subsequent flight of mountain pine beetle was studied using direct observation of emergence, weather radar imagery, and aerial capture. To verify that the daytime, clear-air radar returns seen during this period were indeed generated by airborne mountain pine beetles, aerial sampling in the area covered by the radar was performed using a drogue capture net towed by a singleengine light aircraft. Results verify that airborne mountain pine beetles are being detected by the weather radar and that, during the emergence period, significant numbers of mountain pine beetles can be found at altitudes up to more than 800 m above the forest canopy. An estimate of transport distance indicates that mountain pine beetles in flight above the forest canopy may move 30-110 kmÁday -1 . An estimate of the instantaneous density of mountain pine beetles in flight above the canopy on flight days in 2005 indicate a mean (maximum) density of 4950 (18 600) beetlesÁha -1 .Résumé : Une épidémie du dendroctone du pin ponderosa (Dendroctonus ponderosae Hopk.) a atteint une intensité et une dimension sans précédents dans le centre de la Colombie-Britannique, au Canada, et continue de progresser. En 2005, l'émergence et l'envol subséquent du dendroctone du pin ponderosa ont été étudiés à l'aide d'observations directes de l'émergence, d'images captées par un radar météorologique et de captures aériennes. Pour vérifier que la rétrodiffusion radar de ciel clair obtenue durant le jour pendant cette période était en fait générée par des dendroctones du pin ponderosa en vol, un échantillonnage aérien dans la zone couverte par le radar a été effectué à l'aide d'un filet de capture conique tiré par un avion léger monomoteur. Les résultats confirment que les dendroctones du pin ponderosa en vol sont détectés par le radar météorologique et qu'un nombre élevé de dendroctones du pin ponderosa peut être observé à des altitudes de plus de 800 m au-dessus de la canopée de la forêt durant la période d'émergence. Une estimation de la distance de transport indique que le dendroctone du pin ponderosa en vol au-dessus de la canopée peut franchir 30 à 110 km en une seule journée. Une estimation de la densité instantanée du dendroctone du pin ponderosa en vol au-dessus de la canopée lors des jours de vol en 2005 révèle une densité moyenne (maximum) de 4 950 (18 600) dendroctones à l'hectare.[Traduit par la Rédaction]

The monoterpene α-pinene, a major component of the terpene composition of Pinus spp., has been reported to act as a host-produced kairomone for a variety of bark beetle species, including the mountain pine beetle, Dendroctonusponderosae Hopkins. However, our experiments indicate that α-pinene autoxidizes under normal temperature and atmospheric conditions to form significant quantities of trans-verbenol, an aggregation pheromone for many species of bark beetles. The quantities of α-pinene present in the resin that can flow from small wounds in pine trees appear to be sufficient to produce trans-verbenol at rates similar to those by female beetles that are actively synthesizing the compound.trans-Verbenol can then autoxidize rapidly to form verbenone, with the content of this compound reaching 8% within 13 weeks of exposure to air. Verbenone is often used by scolytids as an antiaggregation pheromone. Approximately 1.9% of the trans-verbenol and 2.7% of the verbenone found in Porapak Q aerations of phloem with boring spruce beetle, Dendroctonusrufipennis (Kirby), females, as well as 0.8% of the trans-verbenol and 0.8% of the verbenone found in aerations of phloem with boring D. ponderosae females, was due to the autoxidation of α-pinene and (or) the release of oxygenated compounds found in the phloem before bark beetle attack. The natural interconversion of α-pinene, trans-verbenol, and verbenone under ambient conditions suggests that many experiments involving the behavioral activity of these compounds require re-evaluation.

The association between 11 species of bark beetles (Coleoptera: Scolytinae) and one weevil (Coleoptera: Entiminae) with the pitch canker fungus, Fusarium circinatum Nirenberg and O'Donnell, was determined by crushing beetles on selective medium and histone H3 gene sequencing. Pityophthorus pubescens (Marsham) (25.00%), Hylurgops palliatus (Gyllenhal) (11.96%), Ips sexdentatus (Börner) (8.57%), Hypothenemus eruditus Westwood (7.89%), Hylastes attenuatus Erichson (7.40%), and Orthotomicus erosus (Wollaston) (2.73%) were found to carry the inoculum. In addition, the root weevil Brachyderes incanus L. (14.28%) had the second highest frequency of occurrence of the fungus. The responses of the insects to a range of verbenone doses were tested in field bioassays using funnel traps. Catches of P. pubescens, a species colonizing branch tips of live trees, were significantly reduced in a log-linear dose-dependent relationship. Catches of I. sexdentatus, an opportunistic species normally attacking fresh dead host material, were also gradually reduced with increasing verbenone dose. Catches of Tomicus piniperda L., O. erosus, Dryocoetes autographus (Ratzeburg), H. eruditus, Xyleborus dryographus (Ratzeburg), Hylastes ater (Paykull), Hylurgus ligniperda (F.), H. attenuatus, and B. incanus were not significantly affected by verbenone. The effects of verbenone were consistent with differences in host-age preference. Semiochemical disruption by verbenone in P. pubescens and I. sexdentatus could represent an integrated pest management strategy for the prevention of the spread of pitch canker disease between different stands. However, several species associated with F. circinatum were unaffected by verbenone, not supporting this compound for prevention of the establishment of potential vectors in Northern Spain.

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