Evidence for deceptive fertility in a wild primate

Alice baniel

ISEM, Montpellier

alice.baniel@umontpellier.fr

Link to seminar: https://umontpellier-fr.zoom.us/webinar/register/WN_1JVwfsmPR5qxnBQcE6zN6g

Abstract: 

Primate sexual swellings have long generated debate about their function – do they reliably indicate female fertility or deceptively blur it? Here, we provide evidence that female primates can manipulate sexual swellings to outwardly indicate fertility while inwardly failing to conceive. Geladas (Theropithecus gelada) exhibit extreme sexual conflict as sexually selected infanticide. When new males take over a group, they often kill dependent infants – a high cost for lactating females. Using 14 years of demographic and hormone data from a population of geladas in Ethiopia, we demonstrate that after takeovers: lactating females immediately resumed external signs of fertility (e.g., sexual swellings); these swellings were far less likely to lead to conception; and all lactating females exhibited a surge in estrogens mediating both fertile (“true”) and non-fertile (“false”) swellings. Critically, lactating females that exhibited post-takeover sexual swellings were less likely to lose their infants to infanticide compared to those that failed to. We propose a strategy whereby sexual swellings of lactating females range from probably deceptive (when infants are highly dependent) to probably honest (when infants could be weaned successfully). These results strongly support that sexual swellings can deceptively blur fertility as a counterstrategy to sexual conflict.

Watch previous seminars on our YouTube channel: https://www.youtube.com/channel/UCrX4IsZ8WIFcDa0ZmC7rcQg