Associations between two species of snapping shrimp, Alpheus inca and Alpheopsis chilensis (Decapoda : Caridea : Alpheidae)

This study examined the association pattern of two snapping shrimp species that inhabit burrows at exposed rocky shores of the Chilean Pacific coast. The two species Alpheus inca and Alpheopsis chilensis were frequently found to share the same burrows. In most burrows an heterosexual pair of each sp ecies was found. A strong positive correlation between the body length of f emale and male conspecifics cohabiting in a burrow was found both for Alphe us inca and for Alpheopsis chilensis. Similarly, a positive correlation exi sted between the mean body length of Alpheus inca and that of Alpheopsis ch ilensis occurring together in one burrow. Thus, a size-relationship between burrow cohabitants exists both in the intra-specific as well as in the int er-specific association of these shrimps. Most females, regardless of their reproductive stage, were accompanied by males. Within a particular burrow, females of the two species often were in the same reproductive stage, i.e. both were with embryos in a similar developmental stage, or both were with out embryos. These data suggest that male and female conspecifics, as well as the pairs of the two species, remain together in the same burrow for rel atively long time periods. It is proposed that the intra-specific communica tion system of snapping shrimp facilitates the development of inter-specifi c associations, such as the one reported herein.