Competitive Exclusion of Dendroctonus rufipennis Induced by Pheromones of Ips tridens and Dryocoetes affaber (Coleoptera: Scolytidae)
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Journal of Economic Entomology. Vol. 91 no. 5.:p. 1150-1161. (1998)
We tested the feasibility of competitive exclusion as a potential management tactic for the spruce beetle, Dendroctonus rufipennis Kirby, using pre-attack baiting with pheromones of 2 secondary species, Ips tridens Mannerheim and Dryocoetes affaber Mannerheim. Spruce beetle attack densities, gallery lengths per square meter, and progeny densities were significantly reduced by up to 78% in individual felled trees baited with the I. tridens pheromones (+/-)-ipsdienol and (-)-cis-verbernol, and the D. affaber pheromones (+/-)-exo-and (+)-endo-brevicomin, or pheromones of both secondary species. A simplified D. affaber bait consisting of only (+/-)-endo-brevicomin also significantly reduced spruce beetle attacks, resource exploitation, and progeny production. Baiting with I. tridens pheromones also reduced spruce beetle attack and success in simulated patches of windthrown trees. Resource exploitation and indirect interference by synomonal inhibition of spruce beetle attack are the most likely competitive mechanisms invoked. Competitive exclusion of the spruce beetle may provide an alternative management tactic where traditional methods based on tree removal, widespread harvesting, and the use of insecticides are not feasible.
KeywordsDendroctonus rufipennis Ips tridens Dryocoetes affaber interspecific competition competitive exclusion pheromone
Poland, Therese M.; Borden, John H. 1998. Competitive Exclusion of Dendroctonus rufipennis Induced by Pheromones of Ips tridens and Dryocoetes affaber (Coleoptera: Scolytidae). Journal of Economic Entomology. Vol. 91 no. 5.:p. 1150-1161. (1998)