Manifestation d'un comportement territorial chez les crevettes pontoniinae associées aux mollusques pinnidae a tuléar (Madagascar)

Shrimps associated with molluscs are generally found in pairs in their host and observations show that this disposition leads to active competition, both intra- (between individuals of same sex) and interspecific.The territory in dispute is the entire palliai ensemble of the mollusc. The weapons are the second pair of pereiopods and their size is of prime importance in determining the outcome of any encounter.In interspecific confrontations, Paranchistus ornatus Holthuis is regularly expelled by Anchistus custos (Forskål), and Conchodytes biunguiculatus (Paulson) will displace both of these species.