In a new paper we show experimentally that adult female cuckoo finches (at left in photo) in Zambia have evolved to resemble harmless and abundant bishop-birds (right), which should help them to slip past being attacked by host parents while they try to lay their egg. However, hosts are not fooled by this attempted deception, and defend themselves against parasitic cuckoo finches and harmless bishop-birds alike. To our knowledge this is the first time that such “wolf-in-sheep’s-clothing” plumage mimicry has been experimentally shown to exist in any adult bird. The paper is by Will Feeney, Jolyon Troscianko, Naomi Langmore and Claire Spottiswoode, and is available open access in Proceedings of the Royal Society of London B.
New paper published on Weber’s Law and mimicry
Our paper ‘Why and how to apply Weber’s Law to coevolution and mimicry’ has been published in the journal Evolution. This perspectives paper, written by Tanmay Dixit, Eleanor Caves, Claire Spottiswoode, and Nicholas Horrocks, argues that Weber’s Law of proportional processing can lead to otherwise counterintuitive predictions about the evolutionary trajectories of mimicry systems. Weber’s Law states that when the magnitude of a stimulus is large, it is more difficult to discriminate a change or difference from that stimulus. In other words, relative differences are more salient than absolute differences. We show that Weber’s Law could have implications for mimicry: when stimulus magnitudes are high, it should be more difficult to discriminate a model from a mimic. This leads to testable predictions about evolutionary trajectories of models and mimics. We also present a framework for testing Weber’s Law and its implications for coevolution.