Tanmay Dixit has commenced his PhD research on egg mimicry in the Cuckoo Finch and egg rejection behaviour by their hosts (family Cisticolidae). He plans to use approaches from applied mathematics, visual ecology and psychology to understand how hosts recognise eggs, and the implications for this on host egg phenotypes and parasite mimicry. This Cuckoo Finch chick, held by Tanmay above, was clearly a successful mimic!
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.
Our paper “Hosts elevate either within-clutch consistency or between-clutch distinctiveness of egg phenotypes in defence against brood parasites” has just been published in the journal Proceedings of the Royal Society of London B. In this study, led by Eleanor Caves, we asked how host eggs evolve adaptations that allow them better to discriminate their own eggs from parasitic eggs. Theoretically, hosts can generate their own individually-distinctive egg ‘signatures’ by laying eggs that appear similar to one another (consistency) but look very different from other individuals’ eggs (distinctiveness). In this new study, we show that host species of two African brood parasites deploy either consistency or distinctiveness, but not both, as defences, and achieve distinctiveness by combining egg colours and patterns in unpredictable combinations.
Congratulations to Mairenn Attwood for being awarded the Janet Moore Prize for teaching in the Department of Zoology at the University of Cambridge, for her outstanding tutorial supervision of final-year undergraduate students, who praised her breadth and depth of knowledge, enthusiasm, and friendliness. Mairenn follows in the footsteps of Tanmay Dixit who was awarded the Janet Moore Prize in 2020. Well done both for inspiring the next generation of behavioural ecologists!
Dr Gabriel Jamie gave a webinar titled: “Africa’s Avian Cheats: Exploring the deceitful ways of cuckoos, honeyguides and parasitic finches”. The talk was part of BirdLife South Africa’s Conservation Conversation series and explores the amazing world of brood-parasitic birds in Africa. You can watch a recording of the talk here: https://youtu.be/7fesIIK2_Wk