Behavioral Responses of the Gypsy Moth 1 in a Wind Tunnel to Air-Borne Enantiomers of Disparlure 2

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Abstract
Mate gypsy moths ( Lymantria dispar L.) in a wind tunnel fitted with a moving floor pattern to provide optomotor feedback to flying moths respond to (+)- cis -7,8-epoxy-2-methyloctadecane [(+)-disparlure] by flight with apparent positive optomotor anemotaxis and reversing anemomenotaxis (an upwind, zigzag flight). From quiesence, the latency to preflight wing fanning decreases with an increasing (+)-disparlure dispenser dosage. Ground speed of flight (the rate of floor movement required to maintain flight in the center of the wind tunnel) decreases with increasing (+)-disparlure concentration suggesting that the attractant concentration can provide an orthokinetic modulation of ground speed. The lowest dispenser dosages of (+)-disparlure tested (1 ng) resulted in greater lateral displacement in the zigzag than 10–1000 ng dosages. At wind velocities of 0.7 and 2.5 m/sec males maintained virtually identical ground speeds by adjusting their airspeed. The (−) enantiomer of disparlure when admixed to (+)-disparlure acts antagonistically to decrease the distance flown, the ground speed and the distance of flight, but the (−) enantiomer does not appear to affect preflight wing fanning latency. Considerable variation occurs in the mean ground speed of individuals, possibly optimum strategies related to orientation in well-defined aerial plumes (rapid flight) and meandering plumes (slow flight).