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John H. Borden - One of the best experts on this subject based on the ideXlab platform.
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Seasonal flight pattern of the western balsam bark beetle, Dryocoetes confusus Swaine (Coleoptera: Curculioniae), in Central British Columbia
Journal of the Entomological Society of British Columbia, 2014Co-Authors: Art Stock, T.l. Pratt, John H. BordenAbstract:Seasonal flight pattern of the western balsam bark beetle, Dryocoetes confusus Swaine, in stands of subalpine fir, Abies lasiocarpa (Hook) Nutt., in north-central British Columbia was monitored for three years using multiple-funnel traps baited with (±)- exo -brevicomin. There were two major flight periods per year, the first commencing in mid- to late June, and the second occurring in mid- to late August. The first flight was predominantly males, while the second flight was composed primarily of females, probably reemerged parent adults. Little flight occurred until within-stand temperatures exceeded 15oC. Traps placed 6 m above ground caught 4 times as many beetles as traps placed 2 m above ground. Our results indicate that semio-chemical-based manipulation of the western balsam bark beetle should be implemented by early May.
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Response of Dryocoetes confusus and D. autographus (Coleoptera: Scolytidae) to enantiospecific pheromone baits
The Canadian Entomologist, 2004Co-Authors: N.l. Jeans Williams, John H. BordenAbstract:Dans des etudes anterieures sur le terrain, les pieges qui ont recolte le plus de scolytes du sapin de l'Ouest, Dryocoetes confusus Swaine, contenaient un melange d'(+)-exo-brevicomine et d'(+)-endo-brevicomine ou d'(±)-endo-brevicomine qui simule la pheromone naturelle de rassemblement produite par les mâles. Une premiere experience de piegeage compare les resultats obtenus avec des melanges enantiospecifiques a liberation restreinte (9:1 d'(+)-exo-brevicomine:(+)-endo-brevicomine ou 9:2 d'(+)-exo-brevicomine:(±)-endo-brevicomine a un taux de liberation de 0,3, 0,1 ou 0,03 mg/jour) a ceux produits par des appâts commerciaux reguliers d'(±)-exo-brevicomine libere a raison de 1,2 mg/jour. Des pieges a entonnoirs multiples appâtes avec les melanges experimentaux ont capture plus de D. confusus que les pieges sans appât, mais seuls les pieges contenant le melange 9:2 (+):(±) a un taux de liberation de 0,3 et de 0,03 mg/jour ont capture significativement plus de coleopteres mâles et femelles que les pieges garnis de l'appât standard. La sensibilite des pieges peut donc etre amelioree par l'addition d'(±)-endobrevicomine. Les pieges garnis d'(±)-exo-brevicomine ont capture des nombres significatifs du scolyte sympatrique D. autographus Ratzeburg. Une seconde experience de piegeage a demontre que D. autographus reagit a l'(+)-exo-brevicomine ou a l'(±)-exo-brevicomine, mais non a l'(-)-exo-brevicomine, ce qui laisse penser que, chez cette espece, l'(+)-exo-brevicomine est le compose principal de la pheromone de rassemblement.
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Comparative Behavioural Responses of Dryocoetes confusus Swaine, Dendroctonus rufipennis (Kirby), and Dendroctonus ponderosae Hopkins (Coleoptera: Scolytidae) to Angiosperm Tree Bark Volatiles
Environmental Entomology, 2003Co-Authors: Dezene P. W. Huber, John H. BordenAbstract:Abstract Synthetic, angiosperm bark-derived volatiles, which elicit antennal responses in a number of coniferophagous bark beetles (Coleoptera: Scolytidae), were tested in groups for their ability to disrupt the pheromone-positive response of the spruce beetle (SB), Dendroctonus rufipennis (Kirby), the western balsam bark beetle (WBBB), Dryocoetes confusus Swaine, and the mountain pine beetle (MPB), Dendroctonus ponderosae Hopkins, to attractant-baited traps. One complex mixture disrupted WBBB response to pheromone-baited multiple-funnel traps to a level not significantly different than that in unbaited control traps. No group of compounds, including a group of green leaf volatiles, was active in disrupting SB response, a result that contrasts other published findings and that is different from the behavioral responses that are elicited by nonhost volatiles in other species of coniferophagous bark beetles. For the MPB, the two green leaf alcohols, 1-hexanol and (Z)-3-hexen-1-ol, were highly disruptive. In...
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Co-baiting for spruce beetles, Dendroctonus rufipennis, and western balsam bark beetles, Dryocoetes confusus (Coleoptera: Scolytidae)
Canadian Journal of Forest Research, 2000Co-Authors: Matthew E Greenwood, John H. BordenAbstract:Co-baiting to contain and concentrate the spruce beetle, Dendroctonus rufipennis (Kirby), and the western balsam bark beetle, Dryocoetes confusus Swaine, was investigated at four locations in British Columbia. Two 9-ha areas were established at each location; one was baited and the other left as a control. Single "interior firs," Abies bifolia A. Murray × Abies lasiocarpa (Hook.) Nutt., or groups of two or three trees, were baited with (±)-exo-brevicomin released at 1.0 mg/24 h. "Interior spruces," Picea engelmannii Engelm. ex Parry × Picea glauca (Moench) Voss, were baited with frontalin released at 0.1, 0.6, or 2.5 mg/24 h, or at 0.6 mg/24 h with alpha-pinene, ethanol, or ethyl crotonate. Another experiment investigated possible interspecific interference between D. confusus and D. rufipennis baits. Ratios of currently attacked "green" trees to previously attacked "red" trees for both insects were significantly higher in baited than in control areas, indicating that populations were contained. Baiting, however, did not attract either insect from a zone surrounding each baited area. There was a significant increase in D. confusus attack when two trees instead of one were baited per centre, no increase in D. rufipennis attack when frontalin was released alone or with the potential adjuvants, no effect of frontalin release rates on the percentage of trees attacked by D. rufipennis, and no indication of cross-repellency between baits.
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DIFFERENTIAL BIOACTIVITY OF CONOPHTHORIN ON FOUR SPECIES OF NORTH AMERICAN BARK BEETLES (COLEOPTERA: SCOLYTIDAE)
The Canadian Entomologist, 2000Co-Authors: Dezene P. W. Huber, John H. Borden, Nicole L. Jeans-williams, Regine GriesAbstract:La conophtorine, une substance volatile de l'ecorce des angiospermes, a ete testee a des taux d'emission de 3,0 et de 0,3 mg/24 h chez quatre especes de scolytes, le Dendroctone du Douglas, Dendroctonus pseudotsugae Hopkins, le Dendroctone de l'epinette, Dendroctonus rufipennis (Kirby), le Scolyte du pin, Ips pini (Say) et le Scolyte du sapin de l'ouest, Dryocoetes confusus Swaine. Les reactions de D. pseudotsugae et d'I. pini (au cours de l'une de deux experiences) et des femelles de D. confusus a des pieges garnis d'une substance attirante ont ete perturbees par la conophthorine et cela en fonction de la dose. Dendroctonus rufipennis ne reagit pas a la conophthorine. Nos resultats demontrent que l'effet repoussant de la conophthorine agit aussi sur Ips DeGeer et confirment les resultats d'experiences anterieures sur D. pseudotsugae. La conophthorine peut s'averer utile pour proteger le bois coupe des invasions de scolytes.
Lorraine E. Maclauchlan - One of the best experts on this subject based on the ideXlab platform.
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Western balsam bark beetle, Dryocoetes confusus Swaine (Coleoptera: Curculionidae: Scolytinae), in situ development and seasonal flight periodicity in southern British Columbia
Journal of the Entomological Society of British Columbia, 2018Co-Authors: Lorraine E. Maclauchlan, Julie E. BrooksAbstract:In situ development and seasonal flight periodicity of the western balsam bark beetle, Dryocoetes confusus Swaine, was observed in subalpine fir, Abies lasiocarpa (Hook) Nutt. stands in southern British Columbia for three years between 1998 and 2002. This study shows developmental differences of western balsam bark beetle in downed and in standing, live subalpine fir. Larval development was slower in the downed trees. Recorded daily minimum phloem temperatures were significantly lower for downed trees than for standing trees during periods of beetle development and flight. There were no significant differences in the recorded daily maximum phloem temperatures between standing and downed trees until late summer, when downed trees saw cooler daily maximum phloem temperatures. This cooler host habitat would provide fewer degree days for insect development. Three distinct larval instars were identified by head capsule measurement. There were two flights per season, the first and major flight occurring from late June to late July, and the other smaller flight occurring in late August. A combination of minimum daily phloem temperatures reaching 5° C and maximum daily phloem temperatures approaching 20° C appeared to trigger the onset of beetle flight, with flight initiated earlier in the season at lower elevations.
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Quantification of Dryocoetes confusus-caused mortality in subalpine fir forests of southern British Columbia
Forest Ecology and Management, 2016Co-Authors: Lorraine E. MaclauchlanAbstract:Abstract The western balsam bark beetle, Dryocoetes confusus Swaine (Coleoptera: Scolytinae), is considered the most destructive mortality agent in high elevation subalpine fir ecosystems, yet the actual impact of this beetle is not well quantified. Past estimates of in-stand losses from D. confusus in subalpine fir-dominated ecosystems have been unreliable due to historically limited and sporadic aerial survey coverage in British Columbia prior to the 1990’s. Tree level aerial assessment of mature subalpine fir in southern British Columbia in 1996–1997, and again in 2014, found mortality from this beetle to be as high as 70%, with mean annual mortality rates ranging from less than one percent to 1.6% in some of the ecosystems surveyed. Over 10% of 101–120 year old stands surveyed in 1996–1997 had no visible mortality, and the mean percent mortality of this youngest cohort was 11% compared to over 17% mortality in all older age classes. By the second survey time, all age classes saw mean mortality estimates more than double, and all stands had some level of D. confusus attack. The highest increase in mortality was recorded in stands over 250 years of age. Stands surveyed in the driest, coldest Engelmann Spruce-Subalpine Fir ecosystem in southern British Columbia sustained the highest levels of attack between survey times, averaging slightly less than 27% mortality, and by 2014 total subalpine fir mortality averaged more than 46%. The rate of mortality over the past two decades has increased. As extreme weather events become more common, particularly in wetter subalpine fir ecosystems, mortality from western balsam bark beetle will be amplified, causing both ecological and economic repercussions in these ecosystems. Results clearly show that subalpine fir stands over 100 years in all ecosystems sustain continuous attack from D. confusus . To minimize future losses to this bark beetle, subalpine fir stands should be managed for a rotation age less than 100 years and mixed species stands promoted where climatically feasible.
Alejandro D. Camacho - One of the best experts on this subject based on the ideXlab platform.
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Response of the western balsam bark beetle, Dryocoetes confusus Swaine (Coleoptera: Scolytidae), to host trees baited with enantiospecific blends of exo- and endo-brevicomin
The Canadian Entomologist, 1994Co-Authors: Alejandro D. Camacho, John H. BordenAbstract:AbstractThe response of the western balsam bark beetle, Dryocoetes confusus Swaine, to subalpine firs, Abies lasiocarpa (Hook.) Nutt., baited with (±)-exo-brevicomin (EXOB) or 9:1 blends of EXOB and endo-brevicomin (ENDOB), in two chiral combinations: (+):(±) and (+):(+), was assessed in a heavily infested stand in British Columbia. Unbaited control trees were not attacked, and the proportion of mass-attacked baited trees was similar for all other treatments. However, trees baited with the (+):(+) blend had the highest number of attacks per square metre, and they were also surrounded by the most attacked trees. The (+):(±) blend was intermediate in attractancy, and (±)EXOB was the least attractive bait. Pheromone-based management of D. confusus infestations may be more effective with the 9:1 blend of (+)EXOB:(+)ENDOB than with the previously used (±)EXOB baits.
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aggregation pheromones in Dryocoetes affaber mann coleoptera scolytidae stereoisomerism and species specificity
Journal of Chemical Ecology, 1994Co-Authors: Alejandro D. Camacho, H D Pierce, J H BordenAbstract:Chemical analysis of whole body extracts and volatiles produced by feeding malesDryocoetes affaber (Mann.) disclosed (+)-exo-brevicomin and (+)-endo-brevicomin [(+)EXOB and (+)ENDOB], as the major insect-produced potential pheromones. Laboratory bioassays and field-trapping experiments demonstrated that (+)ENDOB is the main pheromone component, and (-)ENDOB has an inhibiting effect. EXOB either as (+) or (±) appears to be a multifunctional pheromone. It has a synergistic effect in blends of EXOB and ENDOB in ratios up to 1:1, and it is inhibitory at higher ratios. (-)EXOB was inactive. The most attractive blend forD. affaber was a 1:2 blend of (+)EXOB and (+)ENDOB. When this blend was compared with a 9:1 blend, the best known blend forDryocoetes confusus Swaine, the responses by beetles of each of the two species were highly specific, providing evidence for pheromonal exclusion between the two congenerics. We conclude that the combined effect of chirality and the ratio of geometrical isomers of brevicomin determines both the level of response and the species-specificity of the chemical signal inD. affaber.
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Geometrical and optical isomerism of pheromones in two sympatricDryocoetes species (Coleoptera: Scolytidae), mediates species specificity and response level
Journal of Chemical Ecology, 1993Co-Authors: Alejandro D. Camacho, H D Pierce, John H. BordenAbstract:In a field-trapping experiment, western balsam bark beetles, Dryocoetes confusus Swaine, were highly attracted to a 5∶1 mixture of (±) -exo -and (±)- endo -brevicomin. Beetles in the sympatric species D. affaber (Mann.), were best attracted to a 1∶1 blend of these semiochemicals [either (±)∶(±) or (±)∶(±)], suggesting that both geometrical isomers are pheromone components in these species. In laboratory bioassays and further field experiments, attraction of D. confusus was greatest when the (+) enantiomers of both geometrical isomers of brevicomin were presented in a 9∶1 ratio. Responses by male D. confusus to attractive mixtures were reduced in the presence of (−) -exo -brevicomin. Exploitation of the complete range of variability in pheromone structure (both geometrical and optical isomerism) would allow for optimization and regulation of response levels within a species and also could maintain reproductive isolation among sympatric congeneric species primarily through production and response to species-specific blends.
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GEOMETRICAL AND OPTICAL ISOMERISM OF PHEROMONES IN TWO SYMPATRIC Dryocoetes SPECIES (COLEOPTERA: SCOLYTIDAE), MEDIATES SPECIES SPECIFICITY AND RESPONSE LEVEL
Journal of chemical ecology, 1993Co-Authors: Alejandro D. Camacho, H D Pierce, John H. BordenAbstract:In a field-trapping experiment, western balsam bark beetles,Dryocoetes confusus Swaine, were highly attracted to a 5∶1 mixture of (±)-exo-and (±)-endo-brevicomin. Beetles in the sympatric speciesD. affaber (Mann.), were best attracted to a 1∶1 blend of these semiochemicals [either (±)∶(±) or (±)∶(±)], suggesting that both geometrical isomers are pheromone components in these species. In laboratory bioassays and further field experiments, attraction ofD. confusus was greatest when the (+) enantiomers of both geometrical isomers of brevicomin were presented in a 9∶1 ratio. Responses by maleD. confusus to attractive mixtures were reduced in the presence of (−)-exo-brevicomin. Exploitation of the complete range of variability in pheromone structure (both geometrical and optical isomerism) would allow for optimization and regulation of response levels within a species and also could maintain reproductive isolation among sympatric congeneric species primarily through production and response to species-specific blends.
H D Pierce - One of the best experts on this subject based on the ideXlab platform.
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Two Pheromones of Coniferophagous Bark Beetles Found in the Bark of Nonhost Angiosperms
Journal of Chemical Ecology, 1999Co-Authors: Dezene P. W. Huber, John H. Borden, Regine Gries, H D PierceAbstract:Volatiles from fresh bark of black cottonwood, Populus trichocarpa ; trembling aspen, P. tremuloides ; paper birch, Betula papyrifera ; bigleaf maple, Acer macrophyllum ; red alder, Alnus rubra ; and Sitka alder, Alnus viridis , were collected on Porapak Q and subjected to coupled gas chromatographic–electroantennographic detection analyses by utilizing the antennae of several scolytid beetles ( Dendroctonus pseudotsugae , D. rufipennis , D. ponderosae , Ips pini , and Dryocoetes confusus ). Among the antennally active volatiles identified by coupled gas chromatographic-mass spectroscopic analysis were frontalin, 1,5-dimethyl-6,8-dioxabicyclo[3.2.1]-octane, in the two Alnus species and conophthorin, ( E )-7-methyl-1,6-diox-aspiro[4.5]decane, in the other four species. Field trapping experiments demonstrated that conophthorin had a significant disruptant effect on the response to a pheromone-host kairomone blend by both Dendroctonus pseudotsugae and D. ponderosae . Our results, and the recent identification of other scolytid pheromones in various tree species, pose major questions regarding the evolution and ecological roles of these semiochemicals, including the possibility of Batesian mimicry by the beetles. They also suggest a need for comparative studies on the biosynthetic pathways for these compounds.
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Host compounds as kairomones for the western balsam bark beetle Dryocoetes confusus Sw. (Col., Scolytidae).
Journal of Applied Entomology, 1998Co-Authors: A. D. Camacho, H D Pierce, John H. BordenAbstract:: Six compounds attractive to the western balsam bark beetle Dryocoetes confusus in laboratory bioassays were isolated by micropreparative gas chromatography from steam distilled phloem oil from subalpine fir, Abies lasiocarpa (Hook.) Nutt. In the bioassays (1S)-(–)-α-pinene, p-cymene, terpinolene, (+)-longifolene, (R)-(–)-myrtenal and trans-pinocarveol were attractive at 1 μg doses to both sexes of beetles. When combined with 10 pg doses of (±)-exo-brevicomin, all except terpinolene increased the responses to exo-brevicomin in an additive manner. In field experiments in British Columbia, none of the isolated compounds alone was attractive to D. confusus in multiple funnel traps. When paired singly or together with a 9 : 1 blend of (+)-exo- and (+)-endo-brevicomin released at 0.2 mg per day, (1S)-(–)-α-pinene and (R)-(–)-myrtenal released at 12 and 2 mg per day, respectively, caused a significant increase in response by male beetles over the response to the 9 : 1 blend alone. Myrtenal also increased the response of females. Because it is inexpensive and stable, (1S)-(–)-α-pinene could be used to improve the sensitivity of pheromone-baited traps for monitoring D. confusus. However the pheromone blend alone is a highly efficacious tree bait, and host tree kairomones would probably not be needed in baits used to manipulate D. confusus infestations.
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ENANTIOMERIC COMPOSITION AND RELEASE RATES OF exo -BREVICOMIN INFLUENCE AGGREGATION OF THE WESTERN BALSAM BARK BEETLE, Dryocoetes CONFUSUS SWAINE (COLEOPTERA: SCOLYTIDAE)
The Canadian Entomologist, 1995Co-Authors: A.j. Stock, T.l. Pratt, H D Pierce, John H. Borden, B.d. JohnstonAbstract:AbstractField experiments demonstrated that the western balsam bark beetle, Dryocoetes confusus, responded best to multiple-funnel traps baited with mixtures of (+)- and (−)-exo-brevicomin. (±)-exo-Brevicomin released at 0.8 mg per 24 h performed as well as or better than release rates of from 0.2 to 1.0 mg per 24 h in terms of the number of baited trees which were mass attacked (80%), average attack density, and average number of trees attacked within a 10-m radius of baited trees. Baiting more than one tree in a spot resulted in an intensification of attack on baited trees and increased the number of trees attacked within 10 m of each spot.
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Geometrical and optical isomerism of pheromones in two sympatricDryocoetes species (Coleoptera: Scolytidae), mediates species specificity and response level
Journal of Chemical Ecology, 1993Co-Authors: Alejandro D. Camacho, H D Pierce, John H. BordenAbstract:In a field-trapping experiment, western balsam bark beetles, Dryocoetes confusus Swaine, were highly attracted to a 5∶1 mixture of (±) -exo -and (±)- endo -brevicomin. Beetles in the sympatric species D. affaber (Mann.), were best attracted to a 1∶1 blend of these semiochemicals [either (±)∶(±) or (±)∶(±)], suggesting that both geometrical isomers are pheromone components in these species. In laboratory bioassays and further field experiments, attraction of D. confusus was greatest when the (+) enantiomers of both geometrical isomers of brevicomin were presented in a 9∶1 ratio. Responses by male D. confusus to attractive mixtures were reduced in the presence of (−) -exo -brevicomin. Exploitation of the complete range of variability in pheromone structure (both geometrical and optical isomerism) would allow for optimization and regulation of response levels within a species and also could maintain reproductive isolation among sympatric congeneric species primarily through production and response to species-specific blends.
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GEOMETRICAL AND OPTICAL ISOMERISM OF PHEROMONES IN TWO SYMPATRIC Dryocoetes SPECIES (COLEOPTERA: SCOLYTIDAE), MEDIATES SPECIES SPECIFICITY AND RESPONSE LEVEL
Journal of chemical ecology, 1993Co-Authors: Alejandro D. Camacho, H D Pierce, John H. BordenAbstract:In a field-trapping experiment, western balsam bark beetles,Dryocoetes confusus Swaine, were highly attracted to a 5∶1 mixture of (±)-exo-and (±)-endo-brevicomin. Beetles in the sympatric speciesD. affaber (Mann.), were best attracted to a 1∶1 blend of these semiochemicals [either (±)∶(±) or (±)∶(±)], suggesting that both geometrical isomers are pheromone components in these species. In laboratory bioassays and further field experiments, attraction ofD. confusus was greatest when the (+) enantiomers of both geometrical isomers of brevicomin were presented in a 9∶1 ratio. Responses by maleD. confusus to attractive mixtures were reduced in the presence of (−)-exo-brevicomin. Exploitation of the complete range of variability in pheromone structure (both geometrical and optical isomerism) would allow for optimization and regulation of response levels within a species and also could maintain reproductive isolation among sympatric congeneric species primarily through production and response to species-specific blends.
Kenneth F. Raffa - One of the best experts on this subject based on the ideXlab platform.
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Phloeophagous and Predaceous Insects Responding to Synthetic Pheromones of Bark Beetles Inhabiting White Spruce Stands in the Great Lakes Region
Journal of Chemical Ecology, 2003Co-Authors: Kirsten E. Haberkern, Kenneth F. RaffaAbstract:Tree killing and saprophytic bark beetles exert important ecological and economic roles in North American spruce forests. Chemical signaling among bark beetles, and responses by associate insects such as predators and competitors, have significant effects on the population dynamics and ecology of this community. Synthetic pheromones of primary (tree killing) and secondary (saprophytic) bark beetle species and blank controls were tested using multiple funnel and lower stem flight traps in white spruce forests in Wisconsin, Michigan, and Minnesota. Six phloeophagous and four predaceous species were collected with significant attraction by the bark beetles Dryocoetes affaber, Dryocoetes autographus , and Polygraphus rufipennis , and the predatory checkered beetles (Coleoptera: Cleridae) Thanasimus dubius and Enoclerus nigrifrons. In general, trap catches to synthetic lures resembled the species composition obtained by felling trees and collecting emerging beetles in a companion study, although several species showed differing trends. Some cross attraction occurred among bark beetles and between bark beetles and predatory beetles. For example, P. rufipennis was abundant in traps baited with Dryocoetes spp. pheromones. Thanasimus dubius and E. nigrifrons were collected in significant numbers in traps baited with the pheromone of the spruce beetle ( Dendroctonus rufipennis ), frontalin plus α -pinene. This is a new observation for E. nigrifrons . Attraction of T. dubius to the pheromones of at least three bark beetle species in the Great Lakes region, as well as to several southern and western species, reflects its role as a habitat specialist and feeding generalist. Several other important predators and competitors commonly obtained in pine forests in this region were not obtained in these spruce stands, either in response to synthetic pheromones of spruce colonizing beetles, or in host material colonized by these beetles. Potential differences in predator prey dynamics between spruce and pine ecosystems in the Great Lakes region are discussed.
