Daily energy expenditure during lactation is strongly selected in a free‐living mammal. (21st July 2014)

• Record Type: Journal Article
• Authors: Fletcher, Quinn E.; Speakman, John R.; Boutin, Stan; Lane, Jeffrey E.; McAdam, Andrew G.; Gorrell, Jamieson C.; Coltman, David W.; Humphries, Murray M.; Grémillet, David
• Is Part Of: Functional ecology. Volume 29:Number 2(2015:Apr.)
• Page Start: 195
• Page End: 208
• Publication Date: 2014-07-21
• Subjects: Ecology -- Periodicals; 574.505
• DOI: 10.1111/1365-2435.12313
• Languages: English
• ISSNs: 0269-8463

Abstract

<abstract abstract-type="main" id="fec12313-abs-0001"> <title>Summary</title> <p> <list id="fec12313-list-0001" list-type="order"> <list-item> <p>Energy expenditure is a trait of central importance in ecological and evolutionary theory. We examined the correlates of, the strength of selection on, and the heritability of, daily energy expenditure (DEE; kJ day<sup>−1</sup>) during lactation in free‐ranging North American red squirrels (<italic>Tamiasciurus hudsonicus</italic>).</p> </list-item> <list-item> <p>Over 7 years, lactating squirrels with greater DEE had higher annual reproductive success (ARS; standardized selection gradient: β′ = 0·47; top 12% of published estimates). Surprisingly, positive fecundity selection on lactation DEE for increased ARS did not result because lactation DEE was correlated with typical measures of reproductive performance and/or investment.</p> </list-item> <list-item> <p>We found no evidence of costs of elevated lactation DEE acting through female survival, subsequent year lactation DEE or subsequent year reproduction.</p> </list-item> <list-item> <p>Lactation DEE was not significantly repeatable, and heritability was not significantly different from zero.</p> </list-item> <list-item> <p>Elevated lactation DEE enhances ARS through a link between DEE and an unidentified measure of maternal or environmental quality, but there is limited evolutionary potential for lactation DEE to respond to our documented selection.</p> </list-item> </list> </p> </abstract>