PARENT SESSION
Oral Session #38: Herbivory: Herbivore Response to Plants. Presiding: P. Kleintjes.
Tuesday, August 7, 2001. 1:00 PM to 4:30 PM. Hall of Ideas J.

Field response of scolytid bark beetles to 2-methyl-3-buten-2-ol, a novel alcohol emitted by Ponderosa pine.

Gray, Dennis ¹, Lerdau, Manuel¹, ¹

ABSTRACT- The five-carbon alcohol methylbutenol is one of the principal components of the aggregation pheromone of Ips typographus, the European spruce bark beetle; and has been shown to attract the predators of this forest pest to infested trees. Recently, methylbutenol has been discovered to be emitted in large quantities from the foliage of Pinus ponderosa and several related species found in western North America. It is unknown whether North American bark beetles respond to methylbutenol. We suggest that methylbutenol may function as a defense by 1) interfering with host location at either the primary or secondary attack phase 2) attracting predators of bark beetles to infested trees. These hypotheses were tested for Dendroctonus brevicomis and Ips Paraconfusus by comparing bark beetle and predacious insect capture rates at Lindgren Funnel traps baited with host tree monoterpenes or bark beetle sex pheromones, and different methylbutenol release rates. The presence of bark beetle aggregation pheromone significantly increased capture rates of both bark beetles and their predators; however, methylbutenol release rate had no effect on capture rates.

KEY WORDS: Pinus ponderosa, bark beetle, methylbutenol, pheronone