汽水産端脚類C. volutator (Pallas)の生活史

生殖の半月周期性、または月周期性の適応的意義について(予報)

抄録

Corophium volutator, a mud-flat amphipod, has a prolonged reproductive season from February to November in Amakusa, western Kyushu, and shows semi-lunar (high temperature conditions) or lunar (low temperature conditions) reproductive rhythmicity. The population density of this amphipod changes according to the rainy season, from June to July, and typhoon season, from August to September. Therefore, this period is the critical period, C. volutator shows semi-lunar reproductive cycle, i.e, synchronized reproductive activity. To evaluate the adaptative significance of this reproductive rhythmicity in unpredictable environments a simulation model of reproductive activity and asynchronous one are calculated under various assumptions. As a result, animals with synchronous reproductive activity can produce more progenies than those without synchronous reproduction under low population density and skewed sex ratio (males/females <1).