| Co-Investigator(Kenkyū-buntansha) |
HOI Sen yong Department of Zoology, Universty of Malaya, 動物学教室, 教授
SOMBAT Poovachiranon Phuket Marine Biological Center, Thailand, 主任研究員
KOMAI Tomoyuki National History Museum and Institute, Chiba, 学芸研究員 (20260242)
MATSUMASA Masatoshi School of Liberal Arts and Sciences, Iwate Medical Univerity, 助手 (50219474)
TAKEDA Satoshi Marine Biological Station, Tohoku Univeristy, 理学部附属臨海実験所, 助手 (50171640)
WADA Keiji Department of Biology, Nara Women's Univerity, 助教授 (80127159)
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| Research Abstract |
Mating Systems of Uca
In Uca dussumieri spinata, females are widely dispersed, and males compete by trying to outrace rivals to receptive females. Courtship and mating in this species occur on the surface or in burrows females defend. In contrast, males of U.tetragonon court from and defend burrows to which females come for breeding (resource-defense mating systems). Underground copulations occurred frequently in the burrows males defended, and involved famales who had left their burrows and wandered through the colony. In these, matings also occurred on the surface near burrows that females defended and around which they fed. Surface copulations which occur in U.dussumieri spinata have been modified to a pattern in favor of the resource-defense polygyny in U.tetragonon.
Earthen Structures Built by Ilyoplax Crabs
I.ninqpoensis in Vietnam was found to commonly build an earthern structure, barricade, near its neighbor's burrow, and to perform burrow filling, as I.dentimerosa observed in Korea. But burrow filling was less effective to maintain their territories than barricade building in I.ninqpoensis.
Commensalism
Macrophthalmus banzai provide a home for Ilyoplax pingi in Korea and Uca dussumieri spinata for I.orientalis and others in Malaysia. But the host itself suffers no tangible ill-effects. In both cases, some Ilyoplax crabs had own burrows, and the other had not. In M.banzai and I.pingi, I.pingi contact their burrows with a burrow of M.banzai. Crabs that cohabit in burrows of the host species did not show any aggression toward inhabitants in the same burrow.
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