Cephalopods are brainy creatures capable of performing very complex tasks. Amongst cephalopods, cuttlefish are particularly remarkable because they have the extraordinary ability to display intricate changes in colour and shape, which they utilise as a form of visual communication. Their colours convey specific signals, for example during courtship, aggression or to fend off predators. Although in an ideal world communication signals amongst individuals should always be honest, deception can sometimes be fruitful; that is, if you're not caught! It is a gamble taken sometimes when the benefits that can be gained from cheating are worth the risks of suffering the consequences if the fraud is discovered.
Because of the complexity of the cuttlefish colour signals and the very fast rate at which these can change, dishonest signalling seems like a tactic from which cuttlefish could benefit – especially as mourning cuttlefish, Sepia plangon, populations are male biased and males compete for females, frequently interrupting each other's courtship displays. In a paper recently published in Biology Letters, Culum Brown and his colleagues from Macquarie University in Sydney describe how male cuttlefish deceive other males into believing they are actually females while at the same time trying to court a female; in this way, they can avoid being interrupted during their love dance. Brown and his team noticed that in some instances when a male was courting a female in the presence of another male, the side of the courting male's body facing the other male would exhibit female colouration while the side facing the female would display courtship signals. To determine the frequency and success rate of these deceptions in different types of social groups, Brown and his team observed the visual displays of mourning cuttlefish in the wild in 108 courtship groups. They took photographs of the focus male in the group – that is, the male that was performing the courtship display – and then of all other individuals within the group. In addition, they made similar observations of courtship displays in captive individuals.
The researchers observed many different types of social groups, some with more than one female and some with more than one male, but they only observed deceptive tactics in groups where there was a male courting a single female in the presence of one competitor. This tactic was employed 39% of the times within this social group and through observations on the captive cuttlefish the investigators were able to confirm that successful mating occurred when this tactic was used.
Their results suggest that cuttlefish have very high cognitive capabilities. The authors believe they are able to gauge how likely they are to get caught when using deception, as they only use this tactic when in the presence of one other male, when they are least likely to get caught. Furthermore, in instances when deception was used, the courting male would position himself between the other two individuals such that the female could only see the courtship signals while the other male could only see the female colouration. It's been said that all is fair in love and war. Deceit seems to be fair in cuttlefish and when competing for a potential mate, it is love and war all at once.
