ケフサイソガニの繁殖期と雄の空缶利用行動

抄録

Larger males of the crab, Hemigrapsus penicillatus (DE HAAN), were frequently found hiding in the empty flip-top beverage cans scattered over the intertidal and upper subtidal zones at Hirakata Bay. The frequency with which cans were occupied either by single males or by both sexes showed a marked increase corresponding to the early and late periods of the reproductive season of March through September. The decrease in the frequency in the summer paralleled an increase in the number of reproductive gobies found in the cans, suggesting interspecific competition over possession of the cans. We suppose that the empty-can-possessing habit of the larger males (and also females) of this species is related with their mating activity, but direct evidence is still lacking.