Effect of Verbenone on Attraction of Predatory and Woodboring Beetles (Coleoptera) to Kairomones in Lodgepole Pine Forests

Abstract

The response of bark beetle predators and woodboring beetles to the bark beetle anti-aggregation pheromone, verbenone, was tested in the field with multiple-funnel traps baited with attractant kairomones. Catches of the predators Thanasimus undatulus (Say), Enoclerus sphegeus (F.), Enoclerus lecontei (Wolcott) (Coleoptera: Cleridae), and Lasconotus complex LeConte (Coleoptera: Colydiidae) declined significantly with increasing release rates of verbenone. Lasconotus subcostulatus Kraus, and Corticeus praetermissus (Fall) (Coleoptera: Tenebrionidae) (in two of three experiments), showed no significant response to verbenone. In a third experiment, catches of C. praetermissus increased with verbenone dose. Likewise, catches of the striped ambrosia beetle, Trypodendron lineatum (Olivier) (Coleoptera: Scolytidae), increased with verbenone dose in one experiment, but there was no effect in two other experiments. Verbenone had no effect on the response of Spondylis upiformis Mannerheim (Coleoptera: Cerambycidae). We hypothesize that predators specializing on early successional bark beetles are repelled by verbenone since this compound indicates a late stage attack. Generalist predators and woodborers either do not respond to verbenone at all, or they may be attracted by it.