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Combined measures of mimetic fidelity explain imperfect mimicry in a brood parasite-host system.

Published version
Peer-reviewed

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Abstract

The persistence of imperfect mimicry in nature presents a challenge to mimicry theory. Some hypotheses for the existence of imperfect mimicry make differing predictions depending on how mimetic fidelity is measured. Here, we measure mimetic fidelity in a brood parasite-host system using both trait-based and response-based measures of mimetic fidelity. Cuckoo finches Anomalospiza imberbis lay imperfectly mimetic eggs that lack the fine scribbling characteristic of eggs of the tawny-flanked prinia Prinia subflava, a common host species. A trait-based discriminant analysis based on Minkowski functionals-that use geometric and topological morphometric methods related to egg pattern shape and coverage-reflects this consistent difference between host and parasite eggs. These methods could be applied to quantify other phenotypes including stripes and waved patterns. Furthermore, by painting scribbles onto cuckoo finch eggs and testing their rate of rejection compared to control eggs (i.e. a response-based approach to quantify mimetic fidelity), we show that prinias do not discriminate between eggs based on the absence of scribbles. Overall, our results support relaxed selection on cuckoo finches to mimic scribbles, since prinias do not respond differently to eggs with and without scribbles, despite the existence of this consistent trait difference.

Description

Peer reviewed: True


Funder: DST-NRF Centre of Excellence at the FitzPatrick Institute, University of Cape Town


Funder: Department of Zoology, University of Cambridge

Keywords

Minkowski functionals, avian brood parasitism, coevolution, imperfect mimicry, mimetic fidelity, receiver perception, Animals, Parasites, Biological Evolution, Nesting Behavior, Finches, Sparrows, Ovum, Host-Parasite Interactions

Journal Title

Biol Lett

Conference Name

Journal ISSN

1744-9561
1744-957X

Volume Title

Publisher

The Royal Society
Sponsorship
Biotechnology and Biological Sciences Research Council (BB/J014109/1)
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