Influence of maternal mass and condition on energy transfer in Weddell seals
Article first published online: 12 MAY 2006
Journal of Animal Ecology
Volume 75, Issue 3, pages 724–733, May 2006
How to Cite
WHEATLEY, K. E., BRADSHAW, C. J. A., DAVIS, L. S., HARCOURT, R. G. and HINDELL, M. A. (2006), Influence of maternal mass and condition on energy transfer in Weddell seals. Journal of Animal Ecology, 75: 724–733. doi: 10.1111/j.1365-2656.2006.01093.x
- Issue published online: 12 MAY 2006
- Article first published online: 12 MAY 2006
- Received 16 November 2005; accepted 6 February 2006
- body composition;
- Leptonychotes weddellii;
- maternal expenditure;
- 1Environmental variation influences food abundance and availability, which is reflected in the reproductive success of top predators. We examined maternal expenditure, offspring mass and condition for Weddell seals in 2 years when individuals exhibited marked differences in these traits.
- 2For females weighing 355 kg there was a positive relationship between maternal post-partum mass (MPPM) and lactation length, but below this there was no relationship, suggesting that heavier females were able to increase lactation length but lighter females were restricted to a minimum lactation period of 33 days.
- 3Overall, females were heavier in 2002, but in 2003 shorter females were lighter than similar-sized females in 2002 suggesting that the effects of environmental variability on foraging success and condition are more pronounced in smaller individuals.
- 4There was no relationship between MPPM and pup birth mass, indicating pre-partum investment did not differ between years. However, there was a positive relationship between MPPM and pup mass gain. Mass and energy transfer efficiency were 10·2 and 5·4% higher in 2002 than 2003, which suggests costs associated with a putatively poor-resource year were delayed until lactation.
- 5Heavier females lost a higher proportion of mass during lactation in both years, so smaller females may not have been able to provide more to their offspring to wean a pup of similar size to larger females.
- 6MPPM had only a small influence on total body lipid; therefore, regardless of mass, females had the same relative body composition. Females with male pups lost a higher percentage of lipid than those with female pups, but by the end of lactation female pups had 4·5% higher lipid content than males.
- 7It appears that for Weddell seals the consequences of environmentally induced variation in food availability are manifested in differences in maternal mass and expenditure during lactation. These differences translate to changes in pup mass and condition at weaning with potential consequences for future survival and recruitment.