Direct Evidence for Meteorologically Driven Long‐Range Dispersal of an Economically Important Moth

Abstract

Ecological and evolutionary research on lepidoptera migration has traditionally concentrated on the long—range dispersal of day—flying butterflies. Nocturnal flights at high altitudes and the difficulty in species identification have resulted in a paucity of evidence supporting long—range dispersal of moth species attacking economic crops. Black cutworm (Agrotis ipsilon [Hufnagel]), moths were reared on diet containing a marker dye and were released at Crowley, Louisiana, and College Station, Texas. Traps baited with A. ipsilon sex pheromone were stationed in a line east to west over 618 km. There were six trap lines 108 km apart north to south and two more trap lines 720 km further south. Following release, six male moths were captured after two to four nights in Missouri, Kansas, and Iowa. The climatological conditions that allow this rapid long—range movement were quantified and the data suggest that the moths were traveling at altitudes of <1500 m. These results may provide information on the mechanism for long—range migration of many moth species into the north central United States. These findings also strengthen the compatibility of other components of A. ipsilon physiology and behavior with "oogenesis—flight syndrome" (sexual maturity after long—range flight).