Daily flight activity of Trogoderma variabile (Coleoptera: Dermestidae) and Rhyzopertha dominica (Coleoptera: Bostrichidae)

Abstract

The intrinsic daily flight activity patterns of Trogoderma variabile and Rhyzopertha dominica were determined under Australian field conditions using Johnson and Taylor suction flight traps. There were clear daily flight patterns in response to sunrise and sunset, respectively, as well as temperature effects. For T. variabile males and females the estimated time of peak flight was 4.6 and 7.9 h after sunrise, respectively, and estimated maximum temperature response at 35 °C for males and 30 °C for females. For R. dominica, the estimated time of peak flight was 2 h before sunset and estimated maximum temperature response at 37 °C. The lower thresholds for flight were estimated to be approximately 12, 16 and 16 °C for T. variabile males, females and R. dominica (both sexes), respectively. Relative humidity was strongly linked to temperature and was found not to have important effects on flight after time of day, temperature and day-to-day differences (largely due to seasonal changes in population density) were accounted for. These results generally agree with overseas findings for these species, with R. dominica in Australia showing a narrower flight period in the hours before dusk, less flight in the early morning hours or during the day and wider temperature tolerances than populations studied in the U.S.A. The optimum time for control using a space spray would be when most insects have left the réfugia, which would be early to mid-morning on a warm day for T. variabile and in late afternoon for R. dominica.