Robbie Wilson: University of Queensland

Animals routinely compete for access to limited resources, including food, territories or mates. Because combat is energetically costly and increases the risk of injury or death, individuals should avoid fighting unless they have a reasonable chance of winning. Specialised structures such as teeth, claws or horns can be used to show off potential strength, so that opponents can assess each other without contact and decide whether or not to escalate. In most cases, animals should only fight when the competitors are closely matched, possess similar perceived strengths, and when the resources are valued highly. But what happens if the signal is difficult to interpret, or is an unreliable indicator of strength? Crustaceans use their claws in fighting, but since the claw muscles are hidden within an exoskeleton, competitors cannot determine each other’s true strength without contact. This situation allows some individuals to deceive others and gain more resources by growing large claws that appear strong but are actually weak. In this talk, I examine the costs and benefits of dishonest communication in crustaceans to understand how such strategies evolve in nature. In addition, I use a similar approach to explore the expression of one of the most maligned behaviours in world sport – when soccer players pretend to be kicked by opponents and ‘dive’ to the ground to fool referees. Using these very different but parallel study systems, I will discuss how signals are kept mostly honest in nature and how this impacts human communication when aggression may be based on unreliable information.