Can the dietary conservatism of predators compensa

Authors: Nicola M Marples Johanna Mappes

Publish Date: 2010/10/06

Volume: 25, Issue: 4, Pages: 737-749

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Abstract

The evolution of conspicuous colouration in prey is puzzling because such coloration attracts the attention of predators Antiapostatic selection in which rare prey forms are predated disproportionately often is a second potential obstacle to the evolution of conspicuous colouration in prey as bright novel prey forms are likely to be very rare when they first appear in populations It has recently been postulated that dietary conservatism in predators an extended feeding avoidance of novel prey would allow novel conspicuous prey to survive and multiply despite antiapostatic and conspicuousness effects We tested this hypothesis for a novel prey type arising in an otherwise cryptic population providing a direct test of whether antiapostatic selection or the predators’ wariness to attack the novel prey type is the more important force acting on the novel conspicuous prey We conducted our experiment in the “Novel World” an experimental system designed to test predators’ foraging decisions in a large landscape We found that the conspicuous novel prey suffered high initial costs of conspicuousness compared with cryptic prey since most of these prey were attacked during the first “generation” with no opportunity to “reproduce” However a subset of the 17 birds 24 were following a dietary conservative foraging strategy and they were reluctant to eat the novel prey Interestingly these birds were not more neophobic or less explorative Our data demonstrate how difficult it is for the novel conspicuous prey to survive in cryptic populations but they also highlight the importance of the predator’s foraging strategies in helping to promote the evolution and maintenance of aposematismWe would like to thank the Konnevesi research station for the use of their facilities and in particular Helina Nisu for taking care of the birds We are grateful for the research funding provided for JM by the Centre of Excellence in Evolutionary Research The Academy of Finland and University of Jyväskylä and for sabbatical leave from Trinity College Dublin for NM which allowed these experiments to take place We also thank David Kelly Leena Lindström Mike Speed and two anonymous referees for their many helpful comments on the manuscript Janne Valkonen gave invaluable help with the program R The authors contributed equally to the study

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