Exotic ambrosia beetles threaten the health and productivity of natural and managed forest systems worldwide. Early detection of nascent invasive beetle populations is essential to initiate effective management efforts before catastrophic losses in production and forest biodiversity occur. Current detection tactics for these pests utilize traps baited with ethanol lures placed at high-risk areas, such as ports and shipping hubs, but these are often ineffective at detecting incipient, low-level populations. These methods may not be sensitive enough to achieve early detection and, in turn, inform effective management responses. There is a critical need for advanced methods to detect and manage these potentially destructive beetles. Ambrosia beetles are associated with one or several symbiotic fungi that produce volatile compounds, often alcohols, as a byproduct of their metabolism. Several of these compounds are known to attract exotic ambrosia beetles in laboratory assays, but few have yet to be evaluated in a field setting. In this study, we studied the extent to which a suite of fungal volatile compounds are capable of enhancing the ability of ethanol-baited traps to capture ambrosia beetles at managed and natural forest sites in Indiana.
Results/Conclusions
Fungal volatiles modified the attraction of several ambrosia beetle species to attractant-baited traps. Fungal volatiles failed to enhance the response of ambrosia beetles, but both X. crassiusculus and X. germanus attraction was reduced by two fungal volatiles: isoamyl alcohol and isobutyl alcohol. Additionally, benzyl alcohol reduced attraction across all ambrosia beetle species. Our findings suggest that ambrosia beetles use fungal volatiles as cues to find hosts in the appropriate physiological condition to be susceptible to colonization. These results increase our knowledge of how insects identify susceptible hosts and could be used to increase the efficacy of management tactics.