How does the environment impact female control of fertilisation?

My PhD project aims to identify how different environmental factors can affect a female's ability to actively select some sperm over others for fertilisation, using the fruit fly, Drosophila melanogaster, as a model system. Female mate choice can continue after copulation, within the female reproductive tract, in a process known as cryptic female choice or sperm choice.

Before mating, mate choice is known to be very variable, with different environmental factors affecting the cost of being 'choosy'. Variation in sperm choice after mating has not been studied however, nor has it been linked to different environmental conditions, which is what we aim to explore here. We will develop a novel experimental protocol to measure the extent of female sperm choice, whilst eliminating male affects, and test whether sperm choice varies according to a female's social environment, condition, age or temperature.

In achieving this, we will be able to better understand and predict how our current climate crisis is likely to impact the evolution and reproductive behaviour of species across the animal kingdom.

Summary: In internally-fertilising animals, the female reproductive tract is the arena in which sperm compete to fertilise eggs. This provides females with enormous potential to control fertilisation after mating and shape evolutionary trajectories, with fertilisation outcomes strongly influencing the evolution of male and female reproductive traits through sexual selection and sexual conflict.

However, females of the same species are generally assumed to control fertilisation in the same way. This is surprising, because we know that female mate choice (female control before mating) can be highly flexible, changing according to a female's environment or health. Importantly, the effect of these factors on female control of fertilisation has not been properly tested.

To address this fundamental problem, we will investigate how the environment influences female control of fertilisation using the model fruit fly Drosophila melanogaster. Objectives

1.Develop an experimental protocol for measuring active female control of fertilisation in D. melanogaster, in terms of female behaviour and fertilisation outcomes

2.Experimentally test how a female's social environment influences the strength of post-mating preference for attractive males

3.Experimentally test how a female's age or health influences the strength of post-mating preference for attractive males