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

Tina Cornioley,Henri Weimerskirch,Luca Börger,Stéphanie Jenouvrier,Arpat Ozgul

doi:10.1098/rspb.2017.0397

Abstract

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.

Highlights

Body mass is an important component of an organism’s body condition because it reflects the intrinsic amount of energy reserve available to survive and breed [1]
Body mass and other indices of body condition positively impact adult survival in several species of mammals [5,8,9,10], and in some long-lived birds such as geese and seabirds [11 –13], sometimes the relationship is only apparent in extreme climatic conditions [14]
We found a clear difference between sexes: male mass enhanced performance in four life-history traits, namely adult survival, breeding success, chick mass and juvenile survival, whereas female mass impacted none

Summary

Introduction

Body mass is an important component of an organism’s body condition because it reflects the intrinsic amount of energy reserve available to survive and breed [1]. Body mass and other indices of body condition positively impact adult survival in several species of mammals [5,8,9,10], and in some long-lived birds such as geese and seabirds [11 –13], sometimes the relationship is only apparent in extreme climatic conditions [14]. This is because long-lived species are expected to allocate their resources primarily to survival rather than reproduction [15].

Results

Discussion

Conclusion