Jonah Walker

Biography & Research

Jonah Walker

My research focusses on the evolution of animal and plant signals, particularly in the context of speciation and co-evolutionary interactions between species. I combine behavioural experiments in the field and lab with genomic data to get a truly holistic view of the evolutionary process.

I am fascinated by natural history and the ways in which elegant experiments and genetic analysis can be used to explain the diversity of Life around us. I became interested in science as a child while learning about the extraordinary collection of plants which is housed the Oxford Botanic Garden, where I grew up. As an undergraduate in Cambridge I was able to work on a range of projects, including investigating the genetic basis of wing-pattern signalling in Heliconius butterflies in the central American tropics, and the development of pollinator-attracting signals in Hibiscus flowers. My thesis project, supervised by Andrew Tanentzap, explored the rapid phenotypic and genomic evolutionary responses of Canadian freshwater fleas (Daphnia pulicaria) following invasion of the predatory spiny water-flea (Bythotrephes longimanus).

These early experiences focussed my interests on the evolution of signals and sensory systems during biological diversification. After graduating, I joined the African Cuckoos team. Working with Claire Spottiswoode, Tanmay Dixit, and Nick Horrocks, I am investigating whether whether warbler and weaver host species have evolved eggs which are more vulnerable to thermal or UV damage as a consequence of their arms race with brood-parasitic cuckoo finches. This was prompted by observations that darker (red & olive) eggs have been seen popping during especially hot breeding seasons.

Alongside this work, I began a PhD in 2022 in Cambridge with Joana Meier, for which I am studying genomic hybridisation and mating signal evolution in two spectacular biological radiations: the peacock spiders of Australia (Maratus spp.) and the ithomiine butterflies of South America (Maratus & Mechanitis spp.). I have also worked in Switzerland on patterns of hybridisation and colour evolution in wall lizards (Podarcis muralis).

With my dual background in field-based natural history and lab-based genetics, I am passionate about integrating often disparate strands of biological research — genomic, behavioural, and physiological — to explain natural phenomena. I’m always keen to communicate these findings to the public, especially those living in the places where we are so fortunate to conduct our fieldwork.





  • Livraghi, L., Hanly, J.J., Van Bellghem, S.M., Montejo-Kovacevich, G., van der Heijden, E.S.M., Loh, L.S., Ren, A., Warren, I.A., Lewis, J.J., Concha, C., Hebberecht, L., Wright, C.J., Walker, J.M., Foley, J., Goldberg, Z.H., Arenas-Castro, H., Salazar, C., Perry, M.W., Papa, R., Martin, A., McMillan, W.O. & Jiggins. C.D. 2021 Cortex cis-regulatory switches establish scale colour identity and pattern diversity in Heliconius. eLife 10: e68549.
  • Bladon, A.J., Lewis, M., Bladon, E.K., Buckton, S.J., Corbett, S., Ewing, S.R., Hayes, M.P., Hitchcock, G.E., Knock, R., Lucas, C., McVeigh, A., Menéndez, R., Walker, J.M., Fayle, T.M. & Turner, E.C. 2020 How butterflies keep their cool: Physical and ecological traits influence thermoregulatory ability and population trends. Journal of Animal Ecology, 89: 2440-2450. 


Symposium on moult in tropical birds at International Ornithological Congress

Dr Gabriel Jamie and Dr Chima Nwaogu organised a symposium on “The ecology and evolution of moult in tropical birds” as part of the International Ornithological Congress. The symposium included a Round Table discussion as well as invited talks from a range of speakers including Dr Yahkat Barshep (A. P. Leventis Ornithological Research Institute, Nigeria), Dr Barbara Helm (Swiss Ornithological Research Institute, Switzerland), Dr Oluwadunsin Adekola (FitzPatrick Institute of African Ornithology, University of Cape Town, South Africa & Federal University of Technology, Akure, Nigeria) and Dr Yosef Kiat (University of Haifa, Israel).

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Dr Gabriel Jamie speaks at European Society for Evolutionary Biology conference

Dr Gabriel Jamie was an invited speaker at the European Society for Evolutionary Biology conference in Prague, Czech Republic, as part of the symposium on “Repeated and Parallel Evolution in Adaptive Radiations. Gabriel spoke on “The persistence of polymorphisms across species radiations” building on work conducted together with Dr Joana Meier. To learn more about this research you can read their Trends in Ecology and Evolution paper here.

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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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