Document Detail

The effects of predator learning, forgetting, and recognition errors on the evolution of warning coloration.
MedLine Citation:
PMID:  10937250     Owner:  NLM     Status:  MEDLINE    
This paper demonstrates that the specifics of predator avoidance learning, information loss, and recognition errors may heavily influence the evolution of aposematism. I establish a mathematical model of the change in frequency over time of bright individuals of a distasteful prey species. Warning color spreads through green beard selection as reformulated by Guilford (1990); bright colored forms gain an advantage due to their phenotypic resemblance to other bright forms, which have been sampled by the predator. I use a general classical conditioning model to examine gradual predator learning and forgetting, and then consider the extreme of one-trial learning and no forgetting over time that may occur with very toxic prey. The advantage of conspicuous coloration under these latter conditions depends upon its role in lowering a constant probability of the prey being misidentified and thus mistakenly attacked by a predator, a rarely emphasized factor in the evolution of warning coloration. This constant probability of mistaken attacks can also be interpreted as a constant probability that forgetting has occurred (forgetting does not increase with time) or a periodic decision by the predator to resample avoided prey. I show that when predators learn and forget gradually, as under the general classical conditioning model, it is very difficult for aposematic coloration to become established unless bright individuals cross an often high threshold frequency through chance factors. In contrast, the conditions expected with highly toxic prey promote the evolution of warning coloration more easily, by means from the fixation of very bright mutations to the fixation of successive mutations each of which causes a small increase in a prey's conspicuousness. The results therefore predict that aposematic coloration may have evolved in a different manner in different predator and prey systems. They also suggest that it may be extremely difficult for warning coloration to evolve in more mildly toxic or distasteful prey outside of a mimicry system.
M R Servedio
Publication Detail:
Type:  Journal Article; Research Support, U.S. Gov't, Non-P.H.S.    
Journal Detail:
Title:  Evolution; international journal of organic evolution     Volume:  54     ISSN:  0014-3820     ISO Abbreviation:  Evolution     Publication Date:  2000 Jun 
Date Detail:
Created Date:  2000-09-05     Completed Date:  2000-09-05     Revised Date:  2008-06-04    
Medline Journal Info:
Nlm Unique ID:  0373224     Medline TA:  Evolution     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  751-63     Citation Subset:  IM    
Department of Zoology, University of Texas, Austin 78712, USA.
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MeSH Terms
Avoidance Learning / physiology*
Hair Color / physiology*
Memory / physiology*
Models, Biological
Models, Theoretical
Predatory Behavior / physiology*
Skin Pigmentation / physiology*

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