Migratory birds breeding in Europe often have chronic malaria infections which are assumed to have been picked up on their wintering grounds in Africa. But we know little about their effects in Africa where it’s assumed acute infections might occur. Dr Marjorie Sorensen studied willow warblers during her PhD and found, surprisingly, no obvious ill-effects of malaria parasites on the birds wintering in Zambia. Read more in the original paper by Marjorie Sorensen, Muhammad Asghar, Staffan Bensch, Graham Fairhurst, Susanne Jenni-Eiermann and Claire Spottiswoode, available open access in Journal of Avian Biology.
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.