Climate change and the evolution of insect mating systems

The pervasiveness among animal species of polyandry – i.e., females mating with multiple males – perplexes evolutionary biologists, because it is costly to females (e.g. due to injury and sexually transmitted diseases) yet females can get a lifetime’s supply of sperm from a single male. Polyandry has important ecological consequences, such as increasing extinction risk due to enhanced sexual conflict, and these are particularly severe under harsh environments. Climate change creates more adverse conditions and increases environmental fluctuations, so polyandry may play a pivotal role in how natural populations respond.

It is thought that polyandry can be driven by genetic fitness benefits to females, including bet hedging against uncertain environments and reduced costs of inbreeding. However, these benefits depend critically on the genetic makeup of the female and of the males she encounters, and the environments experienced by her descendants. This can only be understood by using spatially explicit models for evolutionary population dynamics.

This project will use individual-based models for insect species to study the evolution of polyandry in environments that change in space and time. The goals are to predict (i) the conditions under which polyandry is expected to be prevalent (e.g. in fluctuating environments? near range margins? When habitat is patchy?), and (ii) the ecological consequences of polyandry such as accelerated invasions or reduced population viability. The models can be studied by computer simulation or mathematical methods (Ovaskainen et al 2014). Theoretical predictions can be tested using laboratory populations of the fruit fly Drosophila pseudoobscura.

This project would suit a graduate (BSc, 2.i or higher) in a quantitative discipline (e.g. mathematics, physics, computer science) who wishes to apply their skills to evolutionary biology, or a biologist with strong mathematical and/or computational skills. The project will be supervised by Dr. Stephen Cornell (theoretical ecologist) and Dr. Tom Price (evolutionary biologist).