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%.