The economics of evolution: sons or daughters?

The economics of evolution: sons or daughters?

Date & time: 4.30pm 4 June 2021, AEST (Australian Eastern Standard Time)
Location: Online
Speakers: Prof Michael Jennions

One of the most commonly asked question when a woman is pregnant is whether the parents know if it is a boy or a girl. In humans you have an (almost) 50% chance of guessing the answer correctly. But why is this? Can you correctly explain why there are as many sons as daughters born in humans?

I will discuss the evolutionary principles that underlie the evolution of offspring sex ratios in animals. You might be intrigued to learn that offspring sex ratios can vary hugely across different species. Using basic economics ideas about costs and benefits, combined with game theory, evolutionary biologists can predict the conditions under which male-biased or female-biased offspring sex ratios will evolve. Even better, we can then test these theory-based predictions and show that they are surprisingly accurate. These findings provide some of the best evidence for a ’selfish gene’ approach to the study of evolution.

This talk will highlight the world class theory-driven research conducted at the Australian National University. And if your goal is to carry out applied science to become a millionaire, I will suggest a way in which you could apply this seemingly esoteric sex ratio theory to food production.


About the speaker

I grew up in South Africa. My MSc was on sperm competition in frogs, which involved designing a frog condom (yes, a plastic bag works). I was then lucky to get funding for a PhD at Oxford University. I studied sexual selection in a range of animals and plants, which gave me a wide range of experience, but no technical or taxonomic specialty. In early 1996, Patricia Backwell and I headed off to Panama (Smithsonian Tropical Research Institute). I learned the pleasures of sundowners, how to fall off a motorbike, travelled to Barbados and Trinidad, and discovered the virtue of wearing boxer shorts when living in the tropics. In late 1997 my unemployment ended when I received a STRI Fellowship.

I continued my tradition of working on new taxa: parental care and mate desertion in cichlids and life history evolution in a live-bearing fish. I arrived in Australia in 2001. Here I have worked on crickets, beetles, meta-analyses, publication bias, and occasionally helped with fieldwork on fiddler crabs. The current main study animal in our lab is the mosquitofish, Gambusia holbrooki. Think of a colourful tropical freshwater fish. Now remove all the colour - that's Gambusia! On the other hand, they mate a lot and they are very active which makes them ideal for behavioural studies.

Please see the group web site for info on my students, post-docs and collaborators who do all the real work.

Webinar recording