Wednesday, May 15, 2013

The evolution of male mate choice

Posted by Jessica Abbott

At the last group meeting we got to talking about male mate choice, and what factors could favour the evolution of male mate choice.  To follow up on this, I thought it would be interesting to read a relatively recent paper by Sandra South, Göran Arnqvist, and Maria Servedio on this topic.  It's a model that shows that female preference for male courtship can drive the evolution of male mate choice, and was inspired by Sandra's results on the mosquito species she studied during her PhD.
Sabethes cyaneus, a species in which both sexes have ornaments.  Photo by Sandra South.


Sandra H. South, Göran Arnqvist, Maria R. Servedio

Volume 66, Issue 12, pages 3722–3735, December 2012

The evolution of male mate choice is constrained by costs of choice in species with a male-biased operational sex ratio (OSR). Previous theoretical studies have shown that significant benefits of male choice are required, for example, by mating with more fecund females, in order for these costs to be offset and a male preference to spread. In a series of population genetic models we show the novel effect that male mating preference, expressed as a bias in courtship, can spread when females prefer, and thus are more likely to mate with, males who court more. We explore two female preference functions for levels of male courtship, one representing a threshold and the other a weighted female preference. The basic finding generally holds for both preference functions. However, the preference function greatly affects the spread of a male preference allele after the addition of competing males who can court more in total. Our results thus stress that a thorough understanding of the response of females to male courtship is a critical component to understanding male preference evolution in polygynous species.

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