A preliminary study of the population dynamics of Orthetrum j. japonicum (Uhler) in paddy fields (Anisoptera: Libellulidae)

The mark-and-recapture method was applied. Both males and females left the study area immediately after emergence. They stayed along the periphery of the forests in the hills until they attained the reproductive stages. When they became mature, they returned to the paddy fields. The mean longevity of males was considered to be at least 20 days. In the paddy fields, mature males showed territorial behaviour, whereas mature females remained in adjacent bushes. The extent of the territory was calculated as about 5 X 5 m by the estimated density. M ovements between hills and paddy fields were considered to be important for the life history in this species.