High light intensity: A critical factor in the wind-tunnel flight of two scarabs, the rose chafer and Japanese beetle

We analyzed the flight of the rose chafer Macrodactylus subspinosus (E) (Me lolonthinae: Scarabaeidae) and the Japanese beetle Popillia japonica Newman (Rutelinae: Scarabaeidae) in a wind tunnel with controlled humidity, tempe rature, light, and airflow. The data indicate that an optimum combination o f light and temperature dramatically improves their response to lures. Both species took off upwind, oriented to, and contacted the odor source well ( 40-60%) when light intensity was > 50% of a clear day, temperature was 26-2 7 degreesC, and relative humidity was 65-75%.