Natural male-female interactions and territoriality in the fiddler crab Uca capricornis

The behaviour of U. capricornis is not well-known. Consequently, observations were made for approximately 1100 hours over 4 seasons to obtain a general picture of their social system and behaviour. The study was conducted on a large population of Uca capricornis in the vicinity of the mangrove boardwalk in the East Point Reserve, Darwin. Fieldwork was conducted yearly from November-January, 2002-2006.

To obtain a more detailed description of the relationship between males and females, the natural interactions between males and females living as nearest neighbours were recorded. Twenty-one pairs were filmed from overhead for a period of 30 minutes. Any activity was noted, as was any interactions with intruders.

Territoriality was also examined, providing the overall area covered by the crabs within the half hour. By aligning the male and female territories with their respective burrows it was possible to determine the area overlap between them.