Tanmay Dixit

Biography & Research

Tanmay Toucan

I am a PhD student at the University of Cambridge (BA Natural Sciences), studying the evolution and behavioural ecology of brood parasite – host interactions, with fieldwork in Zambia. I graduated from Cambridge in June 2017 and following have studied avian brood parasitism in South Africa and Zambia and interactions between fish species in Trinidadian streams.

Some of my research projects have included studying interactions between pollinators (Heliconius butterflies) and tropical vines (Psiguria), with Prof. Chris Jiggins in Panama, and theoretical work on the interaction between mating systems (specifically self-incompatibility in plants) and genetic barriers with Prof. Nick Barton. I also conducted a meta-analysis on cooperatively breeding vertebrates and maternal effects as one of my Bachelor projects, which has been published in the journal PeerJ.

I am primarily interested in species interactions and behavioural ecology, particularly the consequences of antagonistic arms races on adaptations and animal signals – these interests have been largely inspired by attending seminars and having conversations with members of the Behavioural Ecology Group at Cambridge. Prof. Nick Davies and Prof. Claire Spottiswoode have particularly inspired me and enhanced my interest in both scientific questions and natural history. In particular I have been fascinated by brood parasitism due to the wonderful adaptations, and some seemingly inexplicable maladaptations, that are generated by host-parasite coevolution.

In Zambia I am studying the interactions between cuckoo finches Anomalospiza imberbis and their hosts (family Cisticolidae). I am attempting to understand the mechanisms and adaptive decision-making involved in egg rejection by hosts, as well as why differences exist between some host and parasite eggs. I am collaborating with Prof. L Mahadevan (Harvard) and Dr. Cassie Stoddard (Princeton) to use top-down and bottom-up approaches in studying the evolution of egg signatures and forgeries, and the generation of adaptive repeated randomness. I also aim to understand the effects of coevolutionary arms races, and why outcomes of similar arms races may differ.

Having always been interested in nature, as well as being a keen bird- and wildlife-watcher, I am delighted to be able to pursue these scientific questions in the setting of Zambia’s miombo woodland. A large part of my passion for brood parasitism, ornithology and animal behaviour is inspired by my love of natural history.

Publications

News

Evolutionary Biology Crash Course

Tanmay Dixit was a member of a team organising and lecturing in the inaugural Evolutionary Biology Crash Course. This course, aimed at undergraduate or early-postgraduate students, teaches evolutionary principles to students who have had limited opportunities to be exposed to evolutionary ideas. The course is funded by the Equal Opportunities Initiative Fund of the European Society of Evolutionary Biology (ESEB). Tanmay presented lectures on behavioural ecology and evolution, focussing on kin selection, coevolution, and parasitism. Over 700 students, with the vast majority from the global South, attended the course, which was a resounding success!

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New paper on visual complexity & mimicry

Our paper “Visual complexity of egg patterns predicts egg rejection according to Weber’s Law” has just been published in the journal Proceedings of the Royal Society B. This research was led by Tanmay Dixit, and carried out together with Andrei Apostol, Kuan-Chi Chen, Tony Fulford, Chris Town and Claire Spottiswoode, in a collaboration between biologists and computer scientists. We used machine learning to compute a biologically-relevant measure of egg pattern complexity, and combined this with field experiments in Zambia to investigate how complexity evolves in an arms race between host egg signatures (by tawny-flanked prinias) and parasitic egg forgeries (by cuckoo finches).

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Fieldwork and teaching at APLORI, Nigeria

Dr Gabriel Jamie is continuing his fieldwork on the evolution of polymorphisms in cisticolas and prinias in Nigeria, where he is also a teaching fellow at the AP Leventis Ornithological Research Institute (APLORI). The image shows the 2022 APLORI MSc class during the Global Birding Big Day on 14 May. The team recorded 135 species while walking around the nature reserve surrounding the institute.

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New paper on the genetics of cuckoo finch egg mimicry

Our paper “Genetic architecture facilitates then constrains adaptation in a host-parasite coevolutionary arms race” has been published in the Proceedings of the National Academy of Sciences of the USA. In it, we address the long-standing puzzle of how exquisite mimicry of the eggs of several different host species can evolve within a single species of brood-parasitic bird. We show that in cuckoo finches in Zambia, egg mimicry of different host egg phenotypes is maternally inherited, which allows mothers to transmit host-specific adaptations to their daughters irrespective of which host species the father was raised by. This study was a team effort from colleagues at the University of Cambridge and University of Cape Town (Claire Spottiswoode, Wenfei Tong, Gabriel Jamie), at Boston University (Katherine Stryjewski, Jeff DaCosta, Evan Kuras and Michael Sorenson) and in the Choma community in Zambia (Ailsa Green, Silky Hamama, Ian Taylor and Collins Moya).

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