Diel Periodicity of Emergence and Premating Reproductive Behaviors of Adult Dogwood Borer (Lepidoptera: Sesiidae)

Abstract

The emergence and premating reproductive behaviors of adult dogwood borer moths, Synanthedon scitula Harris (Lepidoptera: Sesiidae), were examined under controlled conditions in the laboratory and in apple orchards in Virginia. The diel periodicity of male response to pheromone sources was recorded using traps baited with commercial pheromone lures and with a recently identified, trinary blend of dogwood borer sex pheromone components. An earlier study reporting a significant effect of pheromone trap height on the capture of male dogwood borer was revisited, using commercial lures and the new pheromone. Under a 16:8 (L:D)-h photo regimen, the emergence of male and female moths showed a diel periodicity, peaking at 0600 hours. Sexual receptivity of female moths, indicated by the onset of calling behavior, occurred in most individuals on the day after emergence and was observed only during the crepuscular period just before and after sunset. Similarly, the capture of male dogwood borer in traps deployed in July and baited with virgin female moths or pheromone lures coincided with the period of female calling behavior, peaking sharply between 2000 and 2100 hours. When pheromone-baited traps were deployed in September, the peak capture of male dogwood borer occurred earlier, between 1900 and 2000 hours. Traps baited with a commercial lure captured significantly more male dogwood borer at 1.8 m (6 ft), whereas those baited with the trinary dogwood borer sex pheromone captured similar numbers of males at elevations ranging from 1.2 to 2.4 m (4–8 ft). Use of the new dogwood borer sex pheromone has tremendously increased the precision of trapping data and has yielded reliable measurements of the behavior and abundance of male moths that pertain directly to improved monitoring and management capabilities.