Rapid colour changes associated with the fiddler crab, Uca capricornis

The purpose of this experiment was to quantitatively examine the rapid colour changes associated with the fiddler crab, Uca capricornis. Experiments were conducted in the East Point Reserve, Darwin from Nov - Jan (04/05 and 05/06). \n\n65 randomly selected crabs were caught (21 males and 44 females) and their ability to change colour over a 20 minute period was assessed using a portable spectrophotometer. \n\nThe results indicate that when caught, or otherwise stressed, U. capricornis are capable of rapidly changing their colour, with short term colour changes more likely in females. In all cases the pattern remained unchanged, but did become more difficult to distinguish as the colours darkened.