Mudballing revisited: Further investigations into the construction behaviour of male Uca tangeri

Male and female Uca tangeri (the only fiddler crab species to inhabit Europ e) construct mudballs from mud excavated from within their burrows. Individ ual males placed similar patterns of mudballs each low tide, suggesting tha t there is some degree of stereotypy. When mudballs were experimentally mov ed further from the burrow or closer to it, males only repositioned those t hat were moved closer, placing them further away again. However, males did not replace mudballs that had been experimentally destroyed at the end of t he mudballing phase when they had started to court females. In binary prese ntation tests, females showed no significant differences in response to mud balls made from different types of mud, or different numbers of mudballs. T hese results are consistent with earlier findings that male mudballs functi on as territory boundaries. However, we provide evidence that male mudballs have no function in female attraction, contrasting with previous studies.