Reproductive Biology and Bioturbatory Activities of Two Sympatric Species of Fiddler Crabs Uca lactea annulipes and Uca triangularis bengali (Decopada : Ocypodidae) at the East Midnapore Coastal Belt of West Bengal, India

Abstract

Two sympatric species of fiddler crabs viz. Uca lactea annulipes and Uca triangularis bengali belonging to order decapoda, family ocypodidae have been taken into consideration in respect of their habitat preference, sex ratio, fecundity and role of bioturbatory activities in sustaining the coastal-estuarine-ecosystem dynamics at an ecotone (Talsari) located in the Midnapore (East) coastal belt of West Bengal, India. A distinct segregation of habitats of these two species was evident from this field study. In general, monthly sex ratios were a clearly male biased for both species. Reproductive potential and intensity of the studied fiddler crabs have been measured by quantifying the relative frequency of ovigerous females and their fecundities. These two crabs have been to be as excellent bioturbator mediators and their bioturbatory activities were found to alter geochemistry of sediments by way of making semidomes (only male of U. lactea annulipes) and mudballs (both sexes of U. triangularis bengali). These bioturbatory structures used to play some role in the social as well sexual interactions of both species.