Temporary loss of a sexual signal (claw loss) affects the frequency of sand structure construction in the fiddler crab, Uca lactea

In iteroparous animals, individual decisions about when and how much to invest in reproduction are related to lifetime reproductive success, and the ability to assess one's own competitive ability in one's current condition is necessary for optimising the reproductive investment. Male fiddler crabs have an enlarged claw which is used for courtship and combat, but they sometimes lose the claw. The clawless males would have disadvantages in courtship and combat until they regenerated the claw. Here it is examined whether males modify their reproductive investment in response to their current condition. Most clawless males did not construct sand structures to attract females; thus, they invested little in current reproduction. Small males were also less likely to construct structures. Clawless and small males may invest little in current reproduction and instead allocate energy to claw regeneration or body growth for future reproduction, or invest in in alternative mating tactic, such as surface mating.