Trap height considerations for detecting two economically important forest beetle guilds in southeastern US forests

Wood-infesting beetles continue to be introduced into new areas at high rates through global trade. Once established, these species can be difficult or impossible to eradicate and can be extremely damaging to both ecosystems and economies. Efforts to detect newly arrived species before they become widespread represent an important early line of defense against these threats. There is considerable interest in optimizing trapping methods to best detect taxa of greatest concern. The purpose of this paper is to explore the role of trap height in influencing detection rates for two economically important guilds of forest Coleoptera [phloem/wood feeders (Buprestidae, Cerambycidae and some scolytine Curculionidae) and ambrosia beetles (scolytine Curculionidae)]. We examine this question using three datasets from southeastern US forests. In general, we found phloem/wood feeders and ambrosia beetles to exhibit contrasting vertical distribution patterns. Whereas phloem/wood feeders generally became more species-rich and abundant with increasing trap height, the opposite pattern was found for ambrosia beetles. Moreover, all species found to be significantly associated with the highest traps were phloem/wood feeders, whereas all but one of the species significantly associated with the lowest traps were ambrosia beetles. It is clear from these findings that detection efforts targeting both guilds will be most effective when traps are deployed at multiple heights in southeastern US forests.