Assessing the flight capabilities of the goldspotted oak borer (Coleoptera: Buprestidae) with computerized flight mills.

Abstract

The goldspotted oak borer, Agrilus auroguttatus Schaeffer (Coleoptera: Buprestidae), is native to southern Arizona and is an invasive wood-boring beetle that has caused considerable mortality to native oak species in southern California. Assessing the dispersal capabilities of this woodborer may help to determine its potential environmental and economic risk within the invaded region, and possibly assist with the development of species-specific management strategies. The flight performance of A. auroguttatus adults under different age, mating, and nutritional status was assessed by tethering individuals to computerized flight mills for a 24-h trial period to collect information on total distance flown, flight times and velocities, number and duration of flight bouts, and postflight weight. The nutritional status and body size (i.e., elytron length) of A. auroguttatus adults had a significant influence on overall flight performance. Mating status and gender had no significant influence on total flight distance, duration, velocity, and flight bout time. Significant interactions between nutritional status and age were observed in the overall flight performance of A. auroguttatus, with decreased flight activity in old (approximately 6 d of age) starved individuals during a 24-h trial period. Overall, results of these flight mill assays indicate that A. auroguttatus is unable to disperse long distances across habitats that lack suitable oak hosts. This work supports the hypothesis that human-aided transportation via infested oak firewood from southern Arizona across the Sonoran desert likely caused the initial introduction, and subsequent satellite infestations of A. auroguttatus within southern California's native oak woodlands.