Mammalian females invest heavily in each of their offspring, but little is known about the magnitude and sources of variation in the most energetically expensive form of maternal investment; milk production [1-5]. Investment strategies may change as females mature because females often begin to reproduce before they have completed their own growth . Milk production may also be an important mechanism for sex-biased investment [5,6]. Here, I present data from 106 rhesus macaque (Macaca mulatta) mothers which show that primiparous mothers produce richer milk for sons than daughters, above a general sex bias among all mothers. This difference seems to reflect the tradeoffs between the benefits derived from additional investment in sons and the costs of diverting energy from maternal growth and development.
ASJC Scopus subject areas
- Biochemistry, Genetics and Molecular Biology(all)
- Agricultural and Biological Sciences(all)