Sexual Differences in Foraging Behavior of Fiddler Crab, Uca sindensis (Decapoda: Ocypodidae)

Fiddler crab females have two small feeding claws while males have only one the other is enlarged and used as a weapon as well as a mate attraction signal. The study was conducted on the small intertidal fiddler crab Uca sindensis in the Abi estuary near Bandar Abbas on the Persian Gulf. Data were collected from September 2007 to August 2008 in order to cover a wide range of ecological conditions experienced by these crabs over the duration of a year. We considered whether males Uca sindensis have behaviorally or morphologically compensated for the loss of one feeding claw. Therefore we measured the sex ratio of surface-active crabs the size of the feeding claws the amount of food processed and the feeding effort (male and female). We showed that males scoop up handfuls of sediment at approximately half the rate of females, but spend more time feeding than do females (70.41%). Males are slightly larger than females, but the relationship of feeding claw to carapace size is not linear: small females have relatively large feeding claws for their size, while large males have relatively large feeding claws for their size. Males and females process equivalent amounts of food on a daily basis. In order to compensate for the loss of one feeding claw, males need to spend a greater amount of time feeding.