体サイズ・密度・季節変化からみたチゴガニ雄のwaving頻度

抄録

The cheliped waving frequency (number of waves per min) of individual male Ilyoplax pusilla (Brachyura, Dotillidae) during the reproductive season was investigated in terms of body size, temperature and season at two sites where the density at one site was ca. 3 times higher than that at the other site. The waving frequency in the high-density site was ca. 1.5 times higher than in the low-density site. The males waved more intensely in the middle reproductive season, but the seasonal change in the waving frequency was not strongly related with the air temperature. There was also no clear association between the body size and the waving frequency, which is contrast with the positive association so far known for several ocypodoid species including I. pusilla. Among body size, site (high or low density), temperature and research period, site (i.e. the population density) was the most important factor to predict the waving frequency.