Research

My primary interests are in the processes that control evolution – how things change over time.

I am currently a PhD student with the MacColl lab at the University of Nottingham. Our group is dedicated to understanding how the environment and ecological processes shape evolution. To do this we investigate the adaptive radiation of three-spined stickleback fish, Gasterosteus aculeatus, on the Scottish island North Uist.

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North Uist is a flooded mosaic of low-level freshwater lakes. Photographed by myself, May 2016.

An adaptive radiation is an amazing phenomenon, in which a myriad of forms and functions diversify from a single starting point, driven by changes in their environment. Adaptive radiations are like the experiment evolutionary biologists dream of setting up, in which you’d start with a collection of animals that are the same, put them into different environments and see how they change over thousands of years. However, adaptive radiations are the ‘end’ of the experiment, and therefore the research we do is to investigate how the fish have changed from their common ancestor (the results) and how their different environments shaped their change (the experiment conditions). Stickleback radiations are ideal for these questions. Bony armoured marine ancestors were trapped in freshwater lakes at the end of the last glaciation. Lakes differ in their environments in available food, predators, water chemistry and parasites, and so each lake has produced a uniquely evolved population of freshwater stickleback.

Stickleback_with_Schostocephalus.jpgA stickleback infected with Schistocephalus worms. By Jtrytin (Own work) [CC BY-SA 4.0], via Wikimedia Commons

Personally, my research addresses evolutionary questions regarding variation in immune responses. In the wild, animals respond to their parasites in different ways, there is no perfect ‘resistance’ strategy. Immune responses have to be optimised for the local environment and so selection drives immune evolution by weighing up things like: resources available for expensive immune responses; risk of autoimmunity against risk of infection; and balancing immune responses against different kinds of co-infecting parasites. Here are some examples of the questions I am investigating:

  • Do immune responses evolve predictably alongside life history?
  • Do repeatable environments promote parallel evolution of immune responses?
  • How do different immune responses change according to seasonal cues?
  • What’s the role of evolved immune responses in selection against hybridization?

6851672066_bc62f32dd2_o.jpgThe pea aphid, Acyrthosiphon pisum, another important animal studied in evolutionary biology. By Andy Murray, via Flickr, licensed [CC BY-SA 2.0]

I have also spent time during my Masters degree at the University of Sheffield investigating the behavioural ecology of pea aphid speciation, Acyrthosiphon pisum, with Professor Roger Butlin. I examined the interactions between aphids and their host plants, and how the two had co-evolved. These amazing insects spend their entire lives living on their host plants. My findings revealed that co-evolved plant defences are important for keeping different types of pea aphid apart, helping them continue to evolve into new species.

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