Adult behaviors of Idea leuconoe was observed by the tracking method in a netted room. The results showed that the initial temperature of eclosion was 23 ℃ and that eclosion mainly occurred at 08:00-09:00. The pupal shell faded to a gold color, and became dry and transparent as animals approached emergence, which revealed the contour and color of the butterfly. Just 1 min was required from the cracking of the puparium to adult emergence from the puparium. The wings were fully extended after approximately 5 min, and were stacked on the back, with a further 1 h being required for the wings to harden. We observed some flight, but no foraging behavior, on the first day of eclosion, with adult insects remaining in a resting state for most of the time. Both male and female butterflies began to forage on the second day after eclosion. Flight activity began as early as 07:30, and stopped as late as 18:40. However, on cloudy days, flight activity began later and stopped earlier. The daily peak time for flying by females was at 10:00-12:00, while two flying peaks were observed for males, at 10:00-12:00 and 14:00-16:00. Flight behavior was affected when temperatures fell below 25 ℃ or rose above 30 ℃. Male butterflies tolerated higher temperatures compared to female butterflies since males were more active than females at 30 ℃. Except for cloudy days, the flight frequency and flight duration of both males and females increased gradually until mating. In the eight days from eclosion to oviposition, the total flight frequency and accumulated flying time of females were 146 times and 186.23 min, flying on average 18 times a day with a cumulative time of 23.28 min per day, resulting in 1.28 min per flight. Similarly, males flew 131 times for 114.43 min during these eight days, on average 16 times and 14.30 min per day, resulting in 52 seconds per flight. There was no significant difference (P > 0.05) between males and females with respect to total flight frequency or flight duration, while this difference was significant among different days (P < 0.05). A positive significant correlation existed between flight frequency and duration time (P < 0.01). In addition, a positive correlation was seen between flight frequency and single flight time (P < 0.01) in the butterfly population. During the eight days from eclosion to oviposition, females visited flowers 53 times, which took up 36.30% of the total flying times. Total feeding time on flowers was 258.87 min, which was equivalent to 139% of total flight duration time. Seven visits took up 38.9% of total daily flying times, representing 32.36 min per day for flower visits and 4.88 min per visit. Males visited flowers 40 times, which was 30.53% of total flying times, with 344.41 min in total spent feeding on flowers, representing 300.98% of overall flying time. Five visits took up 31.25% of total daily flying times, representing 43.05 min per day for flower visits and 8.61 min per visit. There was no significant difference (P > 0.05) between males and females with respect to flight and feeding times. On the sixth day after eclosion, mating mainly occurred at 12:00-16:00. Most mating encounters were very long, some of which lasted more than 10 hours. Both male and female butterflies mated more than once. If the mating process was disturbed, butterflies were able to change location by flying elsewhere in an unseparated state. The first oviposition occurred on the second day after mating, while the last oviposition occurred on the fourth day after mating. Most eggs were deposited in a dispersed manner on the back of host leaves.