Variability in the Reproductive Characteristics of Local Populations of an Intertidal Gastropod, Nerita japonica(Dunker)

Abstract

Abstract: The reproductive characteristics of an intertidal gastropod, Nerita japonica(Dunker), were investigated among eight local populations occurring in different intertidal habitats of Amakusa Shimoshima Island, western Kyushu, Japan. There was significant variation in the morphometry of egg capsules and embryos between rocky shore and stony shore populations of N. japonica, with the rocky shore populations having larger capsule sizes than stony shore populations. In five out of eight populations, fecundity(number of embryos in an egg capsule)increased significantly with an increase in egg capsule size and decreased with mean embryo size. The data showed for the first time that fecundity and egg capsule size, but not embryo size, are related to adult body size among local populations of N. japonica. The present study demonstrates that body size and reproductive characteristics of N. japonica may vary markedly over even small geographic distances. Such variability in the basic traits of a species must have important implications for their life history Strategy.