WIND DRIFT COMPENSATION, FLYWAYS, AND CONSERVATION OF DIURNAL, MIGRANT NEOTROPICAL LEPIDOPTERA

The identification and conservation of migration corridors requires th at migrating organisms are goal-oriented and capable of adjusting for drifting off-course. Migrating birds are capable of wind drift compens ation over water, but no insects have been demonstrated to possess suc h capabilities. Using vector analysis of individual airspeeds, track d irections, ambient windspeeds and wind directions, we quantified withi n-individual variation in compensation for wind drift in two migrating butterfly and one moth species in natural free flight over a lake. Th e pierid Aphrissa statira and nymphalid Marpesia chiron butterflies we re capable of wind drift compensation, whereas Urania fulgens (Uraniid ae) moths were incapable of course correction. Changes in heading acro ss the lake were not indicative of the use of a single landmark for or ientation, and thus the use of two landmarks or the vector orientation of the surface beneath the insect were potential orientation cues. Am ong migrating Aphrissa statira, Marpesia chiron, Phoebis argante, and Urania fulgens, individual headings corrected at least partly for wind drift. For Aphrissa, short-distance compensation over water extended to a long-distance flyway across the isthmus of Panama that is suitabl e for conservation.