Marjorie Sorensen and her international team of collaborators have just published a paper in Ecology and Evolution asking whether longer bird migrations are associated with increased blood parasitism, by exposing birds to a greater variety of parasites. Marjorie and team used stable isotopes to estimate the migration distances of willow warblers wintering in Zambia, and found that this was unrelated to blood parasitism or other indices of health and condition, suggesting that other factors might be more important in determining individual susceptibility to disease in migratory birds.
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.