Post-Doctoral Research Associate

Current Work- The energetics of sperm (ERC funded)

University of Sheffield

I grew up not far from Lancaster, just over the other side of the Pennines. I moved to Edinburgh in 2003 to start my undergraduate degree in Zoology at the University of Edinburgh. After graduating (and a bit of travelling), I came to Sheffield in 2008 to work in Tim Birkhead’s lab as a contract research technician and was drawn in to the world of sperm! I stayed in the lab as a PhD student, and in January 2013, I finally submitted my thesis! Despite this newly found freedom, I decided to stay here in Sheffield where I am currently involved in the ERC funded project (the energetics of sperm) as a post-doctoral researcher.


Research interests


Successful sperm

In general, I am interested in behaviour and reproductive physiology, especially those that are targeted by post-copulatory sexual selection (PCSS). Through comparative studies, our understanding of how selection influences male sperm traits across species is pretty good. However, more attention is needed where the action actually happens – between males and females of single species. In particular, my work has focused on understanding how different aspects of sperm quality (e.g. sperm length, swimming speed) affects fertilisation success in birds.

Making successful sperm

Although we know what a traits a sperm needs for success, the actual process of making sperm is unclear. Therefore, my current research takes a step back (back to basics really), and is focused on understanding spermatogenesis in birds. Once we understand how sperm are made in a single species, we will be better equipped to investigate how selection targets sperm production across multiple taxa. (pictures to come)

I have also been very fortunate to visit colleagues, in Muenster, Germany and in Cape Town, South Africa. Dr Joachim Wistuba has been guiding me through testes stereology, while Professor Gerhard van der Horst taught me everything I know about CASA and introduced me to some characters out in the Karoo!


Other projects

I am involved in a collaboration to locate the genes responsible for the yellow beak colour (a recessive phenotype) in the zebra finch. My PhD data will also be an integral part of an in-house collaboration to map the genes contributing to the variation in zebra finch sperm length and sperm swimming velocity.

I enjoy taking part in the University Outreach events. I am also a STEM ambassador, and I work with local secondary schools informing students about exciting career opportunities through studying STEM subjects (science, technology, engineering and mathematics).



Volunteering is a great way to gain new skills, and meet new people and see new places. I spent a month working with the Scottish Wildlife Trust on Handa Island. During two trips to eastern Australia, I worked on two very different species: (1) the bridled nail tail wallaby with Australian Animal Care and Education (AACE), and (2) vocal mimicry in spotted bowerbirds (with Laura Kelley, who was a PhD student at that time).


Other interests

Outside of work, I love to travel and visit new places (at least one new country every year!).  I also enjoy running half marathons and am hoping to complete my first marathon next year. Copious tea drinking is also a prerequisite for working in our lab, as well as experimenting with new recipes for daytime treats!


Publications list

Bennison, C., Hemmings, N., Slate, J.S. & Birkhead, T.R. Long sperm fertilize more eggs in a bird. Proc. Roy. Soc. B., DOI: 10.1098/rspb.2014.1897

Stapley, J., Reger, J., Feulner, P.G.D., Smadja, C., Galindo, J., Ekblom, R., Bennison, C., Ball, A., Beckerman, A.P. & Slate, J. (2010). Adaptation Genomics: the next generation. Trends in Ecology and Evolution 25: 705-712



Spoken presentations

The behaviour of sperm in competition. ASAB Easter Meeting 2014. Sheffield, UK.

Sperm size and fertilisation success in the zebra finch. BoS Biannual Meeting 2013. The Peak district, UK.


Poster presentations

Sperm dimensions and sperm competition. The Edward Grey Institute Conference 2012, Oxford University (1st prize for best poster). (pdf of this included)

 Sperm dimensions and sperm competition (again). BoS Biannual Meeting 2012. The Peak district, UK.