Range of Attraction of Pheromone Lures and Dispersal Behavior of Cerambycid Beetles

Cerambycid beetles (Coleoptera: Cerambycidae) can locate suitable hosts and mates by sensing pheromones and plant volatiles. Many cerambycid pheromone components have been identified and are now produced synthetically for trap lures. The range over which these lures attract cerambycids within a forest, and the tendency for cerambycids to move out of a forest in response to lures, have not been explored previously. We conducted two field experiments using baited and unbaited panel traps in northern Delaware to investigate these questions. Within forest fragments, unbaited traps that were 2 m from a baited trap captured more beetles than unbaited control traps, suggesting increased cerambycid activity leading to more by-catch in unbaited traps at 2 m from the pheromone source. Traps at further distances from a baited trap did not catch significantly more beetles than equivalent controls. In contrast, male Prionus laticollis (Drury), which were attracted by the likely female-produced sex pheromone 3,5-dimethyldodecanoic acid, were rarely collected in unbaited traps at any distance from baited traps. Outside the forest, baited traps attracted significantly more cerambycids than unbaited traps at distances up to 40 m from the forest edge, with catch generally decreasing between 8 and 40 m from the forest. Some cerambycids were collected in both baited and unbaited traps at all distances from the forest edge, indicating that at least some species dispersed out of the forest independent of any pheromonal attractants. Our results provide context to previous studies that used these pheromone lures, and offer insights into cerambycid dispersal behavior.