How multiple species affect each other’s ever-evolving eggs

May 15, 2017

Brood-parasitic birds lay eggs that mimic those of other species, to trick hosts into incubating their egg and raising their chick. Hosts often fight back by evolving egg colours and patterns that look different from those of their parasites, making an impostor easier to spot. In this study, we tested whether natural selection also drives hosts to evolve eggs that look different from those of other hosts, to avoid being susceptible to their neighbour’s specialist parasites when several host species live side by side. Using data from Major John Colebrook-Robjent‘s wonderful egg collection, we find evidence for this in the hosts of African brood-parasitic birds, which have evolved astonishingly diverse eggs. Read more in the full paper is published in Proceedings of the Royal Society of London B, by Eleanor Caves (former MPhil student), Martin Stevens and Claire Spottiswoode; see also a news article about this research in The Economist.

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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