Body mass and individual fitness in female ungulates: bigger is not always better

被引:211
作者
Gaillard, JM
Festa-Bianchet, M
Delorme, D
Jorgenson, J
机构
[1] Univ Lyon 1, Unite Mixte Rech 5558 Biomet & Biol Evolut, F-69622 Villeurbanne, France
[2] Univ Sherbrooke, Dept Biol, Sherbrooke, PQ J1K 2R1, Canada
[3] Ctr Natl Etude & Rech Appl Cervide Sanglier, Off Natl Chasse, F-55000 Bar Le Duc, France
[4] Alberta Dept Environm Protect, Nat Resources Serv, Canmore, AB T1W 1P1, Canada
关键词
Capreolus capreolus; lifetime reproductive success; life span; Ovis canadensis; phenotypic quality;
D O I
10.1098/rspb.2000.1024
中图分类号
Q [生物科学];
学科分类号
07 ; 0710 ; 09 ;
摘要
In female vertebrates, differences in fatness often correspond to differences in phenotypic quality, suggesting that larger females have greater fitness. Variation in individual fitness can result from variation in life span and/or variation in yearly reproductive success, but no study has yet assessed the relationships between the components of fitness and phenotypic quality while controlling for life span. We tried to fill this gap using data from long-term monitoring (23 years) of marked roe deer and bighorn sheep, two ungulates with very different life histories. In both species, we found a strong positive relationship between an adult female's mass and her probability of reaching old age: over the long term, bigger is indeed better for ungulate females. On the other hand, we found no evidence in either species that heavier females had higher fitness when differences in life span were accounted for: over the short term, bigger is not necessarily better. Our results indicate that, while broad differences in phenotypic quality affect individual fitness, when differences, in life span are accounted for phenotypic quality has no residual effect on fitness. Therefore, within a given range of phenotypic quality, bigger is not always better, for reasons which may differ between species.
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页码:471 / 477
页数:7
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