This week we are pleased to welcome Thomas Merkling from the Friesen lab.

Towards a better understanding of offspring sex-ratio variation in vertebrates


Ever wondered why Celine Dion has three sons and not any other combinations? Sex allocation theory considers the way parents invest in male and female functions according to their relative fitness benefits. Although successfully applied in parasitic wasps for instance, results remain equivocal in birds and mammals. During the talk, two main reasons underlying these inconsistencies will be addressed: the lack of knowledge on 1) the fitness benefits and costs of either sex and 2) the underlying mechanism(s) of sex-ratio biases. First, using a population of a seabird, the black-legged kittiwake (Rissa tridactyla), he investigated both differences in energetic costs and in fitness return between sons and daughters to then predict how offspring sex-ratio should be adjusted. Then, he did a meta-analysis to test for a ubiquitous role of maternal testosterone in sex-ratio biases across birds and mammals. To finish, he will address another remaining mystery: the evolution of environmental sex determination. Using a comparative approach across lizards, he will test the recent prediction that differences in sex-specific survival to maturity can lead to the evolution of temperature-dependent sex determination.

The EEB Seminars run weekly, on Thursdays, in the EEB Lounge of the BioSciences Complex, Room 4338, from 12:30-1:30pm.

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