Major adult behaviors of Pieris rapae crucivora BOISDUVAL were analyzed functionally and their ecological topics were picked up (11 sectional conclusions), based on the field observation by 'single-individual trailing method'. Resting, nectar intake, flying, egg laying and interindividual behaviors were different sexually, seasonally and/or age-dependently. In interindividual behaviors, especially, functions of ascending fight and abdomen erecting were inferred with relation to age and/or population density, and functions of fluttering, wing folding and leaning which become effective during copulation as well. Based on 11 sectional conclusions, it was made clear that males continued to seek females which need males only once, and that consequently males drive females away out of home habitat.