Fathers matter : male body mass affects life-history traits in a size-dimorphic seabird

Abstract

© The Author(s), 2017. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Proceedings of the Royal Soceity B Biological Sciences 284 (2017): 20170397, doi:10.1098/rspb.2017.0397.One of the predicted consequences of climate change is a shift in body mass distributions within animal populations. Yet body mass, an important component of the physiological state of an organism, can affect key life-history traits and consequently population dynamics. Over the past decades, the wandering albatross—a pelagic seabird providing bi-parental care with marked sexual size dimorphism—has exhibited an increase in average body mass and breeding success in parallel with experiencing increasing wind speeds. To assess the impact of these changes, we examined how body mass affects five key life-history traits at the individual level: adult survival, breeding probability, breeding success, chick mass and juvenile survival. We found that male mass impacted all traits examined except breeding probability, whereas female mass affected none. Adult male survival increased with increasing mass. Increasing adult male mass increased breeding success and mass of sons but not of daughters. Juvenile male survival increased with their chick mass. These results suggest that a higher investment in sons by fathers can increase their inclusive fitness, which is not the case for daughters. Our study highlights sex-specific differences in the effect of body mass on the life history of a monogamous species with bi-parental care.This study is supported by the Swiss National Science Foundation project grant no. 31003A_146445 and the ERC Starting Grant no. 337785 to A.O., and is a contribution to the Program EARLYLIFE funded by an ERC Advanced Grant under the European Community’s Seven Framework Program FP7/2007-2013 (ERC- 2012-ADG_20120314 to H.W.). The long-term demographic study at Crozet was supported by the French Polar Institute IPEV (programme no. 109 to H.W.). S.J. acknowledges support from NSF project no.1246407