Victorious crayfish impress the girls

Posted on March 4, 2011

Over the past decade it’s become clear that vertebrate animals such as fish, birds, dolphins and primates can pick up useful social information by “eavesdropping” – in other words, by acting as bystanders during interactions between other members of the same species.  In comparison, we have much less information on the capacity of invertebrates to eavesdrop, and the first experimental evidence for eavesdropping by invertebrates dates back only to 2008.  That work showed that female freshwater crayfish (Procambarus clarkii) prefer to mate with dominant rather subordinate males that they have watched fighting.  It’s now been found that eavesdropping female crayfish need to smell as well as see the sparring males, so it may be that multiple sensory signals make other crayfish easier to identify.  Females aren’t able to identify the dominance status of males that they haven’t observed.  It seems that females recognise males as individuals, rather than as members of a dominance category as was previously thought. 

Reference:   Aquiloni, L., Buric, M. & Gherardi, F.  2010.  Crayfish females eavesdrop on fighting males and use smell and sight to recognize the identity of the winner.  Animal Behaviour 79, 265–269.