Ethanol: dose-dependent flight responses of bark and woodboring beetles, and associated species of Coleoptera

Abstract

In 2007 to 2008, I assessed the effects of ethanol release rate (dose) on trap catches of bark and woodboring beetles, and associated species of predators, in 6 experiments in north-central Georgia. Multiple-funnel traps were baited with ethanol alone or co-baited with α-pinene (with or without the bark beetle pheromones ipsenol and ipsdienol). The following species of bark and ambrosia beetles exhibited a positive dose-dependent response to ethanol, regardless of co-baits: Corthylus columbianus Hopkins, Dryoxylon onoharaense (Murayama), Hylastes porculus Erichson, Hylastes salebrosus Eichhoff, Hylobius pales (Herbst), Monarthrum fasciatum (Say), Orthotomicus caelatus (Eichhoff), Xyleborinus saxesenii (Ratzeburg), Xyleborus species, and Xylosandrus crassiusculus (Motschulsky) (Coleoptera: Curculionidae). Hylastes tenuis Eichhoff (Coleoptera: Curculionidae) exhibited a positive dose-dependent response to ethanol alone but not when traps were co-baited with α-pinene, or α-pinene and bark beetle pheromones. A consistent negative dose-dependent response was exhibited by Ips grandicollis (Eichhoff) whereas results with Ips avulsus (Eichhoff) and Dendroctonus terebrans (Olivier) (Coleoptera: Curculionidae) were variable. Longhorn beetles were unaffected by ethanol dose except for Curius dentatus Newman (Coleoptera: Cerambycidae), which exhibited a positive dose-dependent response to ethanol. Three species of predators exhibited positive dose-dependent responses to ethanol: Temnoscheila virescens (F.) (Coleoptera: Trogossitidae), Platysoma parallelum (Say) (Coleoptera: Histeridae), and Lasconotus species (Coleoptera: Zopheridae). Ethanol is a key kairomone for many species of bark and woodboring beetles.

Keywords: ambrosia beetle; bark beetle; ethanol; host selection; kairomone.