Sexual maturation, body colour changes and increase of body weight in a summer diapause population of the damselfly Lestes sponsa (Hansemann) (Zygoptera: Lestidae)

Due to a reproductive diapause, L. sponsa has a postponed prereproductive period in the southern half of Japan. In 1987, in Kanazawa City, the prereproductive period lasted 70-90 days: emergence commenced from late May, but reproductive behaviour did not begin until late August. During the summer the oocyte development was suppressed and ripe ova did not appear until mid-August. The colour maturation of the female body, however, proceeded without delay, independently of sexual maturation. The colour maturation and spermatogenesis in males also proceeded without delay and almost all males were fully mature in both features by early July, Body weight, exclusive of lipids, also rapidly more than doubled during the colour maturation period in both sexes. Thus, freshly emerged individuals required a post-teneral development not only of the gonads, but also of such basic body structures as e.g. the muscles, the cuticle, etc.