The behavior of adult moths of the sweet potato hornworm, Agrius convolvuli, was investigated in a rearing cage (73 X 85 X 115 cm) under a 16L-8D photoperiod rising an infrared camera-video recorder system. Six different behaviors: climbing, flight, feeding, calling, mating and oviposition were clearly distinguished and counted. The adult moths lived for 4-12 days and most behavior occulted only in the scotophase. Climbing occurred mainly during the first hour of darkness. Flight was most intense around 4 to 5 h after lights-off in mixed-sex populations. The flight activity of males was four times higher than that of virgin females. After mating, females began laying eggs and the flight activity of mated females was eight times higher than that of virgin females. Seventy percent of feeding occurred in the first 4 h of scotophase. Both water-fed and unfed moths mated and laid eggs as well as moths fed on 20% sucrose. Calling behavior by virgin females increased from 3 h after lights-off to the end of. scotophase. Mating was mainly observed during the latter scotophase and copulation lasted 40 to 100 min. Oviposition was highest during the first hour and then gradually decreased. Mated females laid 400-700 eggs and about 80% were oviposited the night after mating. The behavior pattern differed between the sexes and changed day-by-day as adults grew older.