Pheromone mask produced by male Trypodendron lineatum (Coleoptera: Scolytidae)

Abstract

The response of male Trypodendron lineatum in laboratory bioassays was inhibited if gut extract from males was added to an attractive extract of guts from single females. Emergent, postdiapause males, and paired males removed from logs 2 and 7 weeks after attack possessed the mask. Emergent brood males did not. The pheromone mask was still apparent when separate wicks were used for male and female gut extracts, indicating that the mask is olfactory and does not result from a chemical reaction. Gut extract from paired females removed from logs 2 weeks after attack was attractive, indicating that attraction to females in the host would persist were they not accompanied by mask-producing males.