Flight performance of the soybean aphid, Aphis glycines (Hemiptera: Aphididae) under different temperature and humidity regimens.

The soybean aphid, Aphis glycines (Matsumura), is native to eastern Asia and has recently invaded North America, where it is currently the most important insect pest of soybeans. The soybean aphid has spread rapidly within North America, presumably through a combination of active and passive (wind-aided) flight. Here, we studied the active flight potential of A. glycines under a range of environmental conditions using an aphid flight mill. Winged (alate) A. glycines were tested on a specially designed 32-channel, computer-monitored flight mill system. Aphids that were 12-24 h old exhibited the strongest flight behavior, with average flight durations of 3.3-4.1 h, which represented flight distances of 4.6-5.1 km. After the age of 72 h, A. glycines flight performance rapidly declined. The optimum temperature range for flight was 16-28 degrees C, whereas optimum relative humidity was 75%. Our findings show that A. glycines posseses a fairly strong active flight aptitude (ability and inclination) and point to the possibility of flight initiation under a broad range of environmental conditions. These results have the potential to aid forecasting and management protocols for A. glycines at the landscape level.