Antler size in red deer: Heritability and selection but no evolution

University of Cambridge, Cambridge, England, United Kingdom
Evolution (Impact Factor: 4.61). 09/2002; 56(8):1683-95. DOI: 10.1554/0014-3820(2002)056[1683:ASIRDH]2.0.CO;2
Source: PubMed


We present estimates of the selection on and the heritability of a male secondary sexual weapon in a wild population: antler size in red deer. Male red deer with large antlers had increased lifetime breeding success, both before and after correcting for body size, generating a standardized selection gradient of 0.44 (+/- 0.18 SE). Despite substantial age- and environment-related variation, antler size was also heritable (heritability of antler mass = 0.33 +/- 0.12). However the observed selection did not generate an evolutionary response in antler size over the study period of nearly 30 years, and there was no evidence of a positive genetic correlation between antler size and fitness nor of a positive association between breeding values for antler size and fitness. Our results are consistent with the hypothesis that a heritable trait under directional selection will not evolve if associations between the measured trait and fitness are determined by environmental covariances: In red deer males, for example, both antler size and success in the fights for mates may be heavily dependent on an individual's nutritional state.

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Available from: Loeske E B Kruuk, Oct 22, 2014
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    • "Omitted confounders have been addressed in the selection (but not performance) literature (Price et al. 1988; Rausher 1992; Queller 1992; Scheiner et al. 2002; Kruuk et al. 2002; Hadfield 2008; Morrissey et al. 2010; Shaw and Geyer 2010; Stinchcombe et al. 2013). What is missing from this literature is any analysis of the sensitivity of effect estimates to the presence of random, omitted confounders. "
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    • "These findings reveal a new function for male red deer antlers and suggest that among mammals the degree of elaboration of male secondary sexual characters may signal important aspects of male reproductive quality to females and males. Previous studies demonstrated that antler size is related to the number of calves fathered by males, and it has been assumed that this is exclusively the result of males with large antlers being able to win more fights with other males (Kruuk et al. 2002). Our findings suggest that males with large antlers could also achieve higher reproductive success through their enhanced ability to win fertilizations both in competitive and non-competitive contexts and the possible preferences shown by females to mate with them. "

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