writing / about / science + mating-signals + energy-reserves + lunar-cycle

At low tide, male fiddler crabs Uca annulipes stand at the entrance to their burrows and frantically waving one of their claws to attract passing females. Waving is the cue which females use to choose a mate - so why do some males wave more than others? The ‘honest signalling’ hypothesis explains why bigger males wave more than smaller males - waving is a costly activity, and only bigger, higher quality, crabs have enough energy reserves to bear the expense. Waving, in this case, is ‘honest’ because the cost means weaker individuals can’t ‘lie’.