Study on the behaviour of two fiddler crabs, Uca sindensis and Uca annulipes (Decapoda: Ocypodidae), in Bandar Abbas, Iran

This study was carried out on the behaviour of two species of sympatric fiddler crabs on Abi estuary, Bandar Abbas, Iran. Species differences in activity level, grooming, burrowing, muddy structure construction and feeding were all related to their habitat and food source. The more common Uca annulipes lives in low muddy areas along the edges of small streams while Uca sindensis lives in small patches on the higher areas with sandier sediment. At low tide, both species spent most of their time feeding, while at high tide they retreated into their burrows. Both species frequently walked while feeding and interacted aggressively. There were similarities in the feeding behaviour of these species: they fed at the same times of the tidal cycles, they were more likely to engage in courtship and mating behaviour during February-September and were least aggressive at this time. In both species, crabs excavated mud balls from their burrows and placed them away from their burrow entrances. There were, however, also differences between the species. Uca annulipes constructed mud hoods at the entrance to their burrows while U. sindensis did not; and the species differed in feeding rate