抄録
Larvae of a beetle, Tribolium freemani HINTON, showed similar patterns of increase in head capsule size under both isolated and crowded conditions during the first seven larval stadia. Isolated larvae then pupated about 28 d after hatching. Under crowded conditions, larvae continued to undergo larval ecdyses without any further increase in head capsule width, suggesting the occurrence of stationary larval ecdysis. When larvae were transferred from crowded conditions to isolated conditions on day 25 or later, pupation soon followed. The time required fro pupation after the transfer was almost constant. Synthetic JH I and JHAs (methoprene and pyriproxyfen) inhibited pupation of crowded larvae even after isolation, and induced stationary larval ecdysis, mimicking the effect of crowding. These results support the hypothesis that crowding inhibits pupation through inducing relatively high JH titres in larvae of this species.
