|Intraspecific behaviors and major cheliped sexual dimorphism in three congeneric callianassid shrimp|Shimoda, K.; Wardiatno, Y.; Kubo, K.; Tamaki, A. (2005). Intraspecific behaviors and major cheliped sexual dimorphism in three congeneric callianassid shrimp. Mar. Biol. (Berl.) 146(3): 543-557. hdl.handle.net/10.1007/s00227-004-1453-0
In: Marine Biology. Springer: Heidelberg; Berlin. ISSN 0025-3162, more
|Authors|| || Top |
- Shimoda, K.
- Wardiatno, Y.
- Kubo, K.
- Tamaki, A.
Decapod callianassid shrimps are usually solitary occupants of their burrows. They are known to show distinct sexual dimorphism of the major cheliped, which is used as a weapon for intraspecific fighting. Three species of Nihonotrypaea occur in an estuary in southern Japan; they consist of two tidal flat species (N. harmandi; N. japonica) and one boulder beach species (N. petalura), with maximum population densities of 1,400, 340, and 12 m-2, respectively. The major cheliped size and total length of shrimp were recorded from each population. The degrees of major cheliped sexual dimorphism were ordered as N. harmandi >N. japonica >N. petalura. In the laboratory, intra- and intersexual behaviors at forced encounters between two shrimps were recorded, for the former behavior throughout the year and the latter in the non-breeding season. At their intersected burrows, the shrimps either fought or retreated or filled the burrow crack. Males interacted aggressively with each other, with the intensity being N. petalura >N. harmandi ˜N. japonica. Females of the tidal flat species were non-aggressive, while those of N. petalura were as aggressive with each other as were males. Intersexually, males of all species and females of N. petalura were much less aggressive than intrasexually. In N. petalura only, burrow-sharing behavior between sexes occasionally occurred. The interspecific difference in these behaviors is in parallel with the degree of major cheliped sexual dimorphism. Different intensities of intrasexual competition for mates could have been imposed by the different population densities of these species.