Some effects of endo -brevicomin background on southern pine beetle (Coleoptera: Curculionidae: Scolytinae) aggregation behavior

Abstract

Semiochemical background in the environment can influence insect orientation to release points of the sameor different semiochemicals. endo-Brevicomin is a pheromone component of the tree-killing bark beetleDendroctonus frontalis Zimmermann (Coleoptera: Curculionidae: Scolytinae) that has a biphasic dose–responsecurve, enhancing attraction at low release rates but reducing attraction at high rates. We investigated the effectof artificial manipulation of background levels of endo-brevicomin on D. frontalis responses to sources ofaggregation attractant in the field. Traps baited with the aggregation pheromone component frontalin andthe host odor alpha-pinene were deployed either with or without a background of endo-brevicomin producedby three surrounding dispensers of this semiochemical each located 20 m away. Two tested levels of endobrevicominbackground caused catches to increase by an order of magnitude above those in the absence ofbackground. Presence of background also altered the beetles' biphasic dose–response when endo-brevicomindispensers were added to traps. Background reduced or concealed attraction-enhancement otherwiseobserved for low-release dispensers added to traps, and it decreased the release rate necessary to producereductions in catches. We propose that spatial variability in abundance of natural, background sources of endobrevicominin the environment (i.e., infested trees) is a cause of the observed variability in effects of endobrevicomindispensers on southern pine beetle behavior in the field. Furthermore, our results illustrate thepotential complexity of the density-dependent effects of biphasic pheromone components on bark beetle massattack and colonization behavior.

Citation

Sullivan, Brian T; Brownie, Cavell. 2021. Some Effects of endo -Brevicomin Background on Southern Pine Beetle (Coleoptera: Curculionidae: Scolytinae) Aggregation Behavior . Environmental Entomology. 37: 899-. https://doi.org/10.1093/ee/nvab092.