Sex and size affecting time allocations for activities in Uca annulipes (H. Milne Edwards, 1837)

Abstract

We investigated the amount of time that large and small, male and female fiddler crabsUca annulipes(H. Milne Edwards, 1837) spent on feeding, walking, standing, grooming, burrowing, inside burrows, fighting, and courtship waving. We video-recorded the activities of 45 males (22 small and 23 large), and 39 females (19 small and 20 large) each for 5 min, and calculated the percentage of time spent on each activity/crab. Our results showed that both sexes spent more time on feeding than on other activities. Males spent more time on building burrows, walking, and grooming than females, and females spent more time inside burrows than males. Smaller males spent more time on feeding, and less time on building burrows and on waving than larger ones. There were no relations between female body size and activities. Feeding rate/feeding claw was higher in males than in females, and crab body size was negatively associated with feeding rate/min.