New paper on the genetics of cuckoo finch egg mimicry

Apr 12, 2022

Cuckoo finch eggs from Zambia on the cover of PNAS

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 for the first time unequivocally supports an elegant hypothesis proposed by Reginald Punnett in 1933. This mechanism of inheritance has allowed egg mimicry of multiple hosts to evolve and remain distinct within cuckoo finch matrilines, that we show have been perfectly host-specific for up to two million years or more. However, we further suggest that maternal inheritance is in fact a double-edged sword for parasites, because it appears to hamper further adaptation in coevolutionary arms races with their hosts, which we show to inherit egg appearance from both parents. 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).

 
For a summary of the research and photos of the eggs, their habitat, and the fieldwork in progress, please see this web story by the University of Cambridge  also see news coverage including from The Daily MailThe IndependentPopular Science and Salon

 

News

New paper on imperfect egg mimicry

Our paper “Combined measures of mimetic fidelity explain imperfect mimicry in a brood parasite-host system” has just been published in the journal Biology Letters. This study was led by Tanmay Dixit, and carried out together with Gary Choi, Salem al-Mosleh, Jess Lund, Jolyon Troscianko, Collins Moya, L Mahadevan, and Claire Spottiswoode, as part of a collaboration between our group and Prof. Mahadevan and his lab at Harvard University. Together we combined mathematical tools and field experiments in Zambia to quantify a key difference – “squiggle” markings – between the eggs of hosts (tawny-flanked prinias) and parasites (cuckoo finches). We showed that suboptimal behaviour on the part of prinias allows cuckoo finches to get by with an imperfect copy of prinia eggs.

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New paper on host aggression and hawk mimicry

Our paper “Aggressive hosts are undeterred by a cuckoo’s hawk mimicry, but probably make good foster parents” has just been published in the journal Proceedings of the Royal Society B. In the paper, we investigate the costs and benefits to the African cuckoo of specializing on a highly aggressive host species, the fork-tailed drongo.

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African Cuckoos Team at the Pan-African Ornithological Congress

The African Cuckoos Team had a fantastic time at the Pan-African Ornithological Congress (PAOC15), this year held in Vic Falls, Zimbabwe. Dr Chima Nwaogu gave a plenary talk on “Differing Priorities in the Timing of Annual Life History Events”, while Professor Claire Spottiswoode and Silky Hamama presented during a roundtable session on communities in conservation and research. Silky also presented a poster, with Claire, Jess Lund, Mairenn Attwood and Cameron Blair each giving research talks as well. 

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