Habitat selection and population parameters of Sympetrum infuscatum (Selys) during sexually mature stages in a cool temperate zone of Japan (Anisoptera: Libellulidae)

The mark-and-recapture method was used to study the population parameters of sexually mature adult S. infuscatum in a forest-paddy field complex in the cool temperate zone of Japan. After emergence, they moved into the forest gaps, and they remained and fed exclusively in the forest gaps throughout their lives. Mature 6 3 captured outnumbered mature 5 9 on each sampling day in the paddy fields, but not in the gaps. However, the estimated daily numbers in both habitats and/or the whole survey area roughly indicated a 1:1 sex ratio, The estimated daily survival rates and daily immigrations showed that 9 9 were apt to stay in the forests, while 3 3 sometimes dispersed, though 9 9 in the paddy fields tended to have a long-range flight. In the morning, some of the paired couples flew to the paddy fields in tandem and oviposited on the wing; these were so-called flyers. The rest remained in the forests the entire day; these were designated as perchers. The forest gaps were thus important for the life cycle of this species both as feeding and roosting sites.