Mimicry in motion and morphology: do information limitation, trade-offs or compensation relax selection for mimetic accuracy? (Q7294)

Many animals mimic dangerous or undesirable prey as a defence from predators. We would expect predators to reliably and exclusively avoid animals that closely resemble dangerous prey, yet imperfect mimics are common. There have been many hypotheses suggested to explain imperfect mimicry, but comparative tests across multiple mimicry systems are needed to determine which are applicable, and which—if any—represent general principles of imperfect mimicry. We tested four hypotheses on Australian ant mimics and found support for only one of them: the information limitation hypothesis. A predator with incomplete information will be unable to discriminate some poor mimics from their models. We also show that since predators must make decisions while they are learning, they are likely to never sample broadly enough to gain and utilise the full information needed to discriminate poor mimics from their models. We found no evidence that one accurate mimetic trait can compensate for another, or that rapid movement reduces selection pressure for good mimicry. Based on our results, we argue that information limitation is likely to be a general principle behind imperfect mimicry of any complex traits, while interactions between components of mimicry may apply to some mimicry systems but not others.