Burrow excavation and mudballing behaviour of the fiddler crab Uca annulipes (H. Milne Edwards, 1837) from southern Thailand

Abstract

We video-recorded and examined the burrow building behaviour of small and large males and females of Uca annulipes (H. Milne Edwards, 1837). Males took a longer time than females, and larger crabs took a longer time than smaller ones, to build burrows. Higher numbers of mudballs were excavated from inside the burrows during the build of the burrows by males than by females, and by larger crabs than by smaller ones. Crab carapace width was positively correlated with the time required to build burrows, and with the number of mudballs excavated from inside the burrows during the build of these burrows. We observed that 82% of the females placed the mudballs near their burrow entrance, whereas 85% of the males placed the mudballs far from their burrow entrance. After building the burrows, 71% of the females went inside the burrow and plugged the burrow entrance, and 90% of the males foraged for food.