Why it pays to cheat when courting a cuttlefish

Cuttlefish have been found to use two-tone camouflage to attract females on one side and hide from males on the other according to research published in Royal Society Journal Biology Letters today.

Culum Brown and his team at Macquarie University, Sydney, observed male cuttlefish deceiving rival males by displaying male courtship patterns to receptive females on one side of their bodies, and simultaneously displaying female patterns to rival males on the other, thus preventing the rivals from disrupting courtship. This behaviour was detected in both the laboratory and the field.

The Mourning cuttlefish (Sepia plangon) in the study are found along the east coast of Australia. Males generally exhibit a pattern of pulsating stripes, whereas females have mottled coloration. During the observed courtship behaviour, the males coloured themselves distinctly half and half.

Cuttlefishes’ ability to rapidly change the texture and colour of their skin is unique and they use it to good effect to ambush prey and hide from predators.  However, although it evolved for this purpose, it is now abused as described in 39% of courtship cases.

Brown notes that, “The old adage that cheaters never prosper is far from applicable in the animal kingdom.” However, the proportion of cheats in a population generally remains low, because the cheat’s bluff is occasionally called and the costs of being caught can be high. In this case, if the rival male catches the deceptive male, a fight will ensue. Thus the male cuttlefish only deploy this tactic in situations where the deception is unlikely to be discovered and punished by rivals; this is usually when he can only be seen by one female and one male, making dual-camouflage a lot easier.

The use of tactical deception in such a complex communication network indicates that social interactions have played a key role in the evolution of cuttlefish and other cephalopods’ brains.