TY - JOUR
T1 - Maternal condition does not influence birth sex ratios in anubis baboons (Papio anubis)
AU - Silk, Joan B.
AU - Strum, Shirley C.
N1 - Funding Information:
A number of agencies and many individuals contributed to the translocation and its long-term monitoring. SCS thanks the Office of the President and the Ministry of Education, Science and Technology for research clearance, the Institute of Primate Research (IPR) and the African Conservation Centre (ACC) for sponsorship. The Jessel family's open mindedness and hospitality have been crucial throughout these many years. The field team and the computer lab team included more than 30 Kenyans. Special thanks go to Patrick Kingwa, Thomas Kingwa, Lawrence Kinyanjui, Martin Lusweti, Josiah Musau, Martin Sati, Patrick Mwangi, James King'aa, Francis ole Molo, David Muruiri, Pambah Goddines, George Kebaya, Rose Waiganjo, Belta Weema and Steve Mutonga. Strum also thanks Dr. Andy Whiten and the St. Andrews University researchers for contributions to project records on STT troop from 1985 to 1997. We thank Peter Kappeler and two anonymous reviewers for thoughtful comments on the manuscript.
PY - 2010
Y1 - 2010
N2 - Trivers and Willard predicted that when parental condition has differential effects on the fitness of male and female offspring, parents who are in good condition will bias investment toward the sex that benefits most from additional investment. Efforts to test predictions derived from Trivers and Willard's model have had mixed results, perhaps because most studies have relied on proxy measures of parental condition, such as dominance rank. Here, we examine the effects of female baboons condition on birth sex ratios and post-natal investment, based on visual assessments of maternal body condition. We find that local environmental conditions have significant effects on female condition, but maternal condition at conception has no consistent relationship with birth sex ratios. Mothers who are in poorer condition at the time of conception resume cycling significantly later than females who are in better condition, but the sex of their infants has no effect on the time to resumption of cycling. Thus, our findings provide strong evidence that maternal condition influences females' ability to reproduce, but females do not facultatively adjust the sex ratio of their offspring in relation to their dominance rank or current condition.
AB - Trivers and Willard predicted that when parental condition has differential effects on the fitness of male and female offspring, parents who are in good condition will bias investment toward the sex that benefits most from additional investment. Efforts to test predictions derived from Trivers and Willard's model have had mixed results, perhaps because most studies have relied on proxy measures of parental condition, such as dominance rank. Here, we examine the effects of female baboons condition on birth sex ratios and post-natal investment, based on visual assessments of maternal body condition. We find that local environmental conditions have significant effects on female condition, but maternal condition at conception has no consistent relationship with birth sex ratios. Mothers who are in poorer condition at the time of conception resume cycling significantly later than females who are in better condition, but the sex of their infants has no effect on the time to resumption of cycling. Thus, our findings provide strong evidence that maternal condition influences females' ability to reproduce, but females do not facultatively adjust the sex ratio of their offspring in relation to their dominance rank or current condition.
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U2 - 10.1371/journal.pone.0012750
DO - 10.1371/journal.pone.0012750
M3 - Article
C2 - 20877648
AN - SCOPUS:77958510746
SN - 1932-6203
VL - 5
SP - 1
EP - 7
JO - PloS one
JF - PloS one
IS - 9
M1 - e12750
ER -