Making sperm: the energetic cost of testes and sperm

One of the most exciting areas of research at the present time is in the field of post-copulatory sexual selection. Sperm competition is virtually ubiquitous across the animal kingdom and has resulted in the evolution of a wide range of behavioural, anatomical and physiological adaptations. Sperm competition is especially prevalent among birds even though most species are socially monogamous. Indeed, we know more about sperm competition in birds than in almost any other animal group. We know for example, that some adaptations operate in concert, such as longer sperm and larger testes, but sometimes they trade-off against each other, such as sperm size versus number. One of the most consistent adaptations across the animal kingdom to sperm competition is testis size: species in which females are promiscuous typically have relatively large testes. Large testes generally produce more sperm, but larger testes are also more costly than smaller ones. However, as yet, we have no idea about the energetic costs of making sperm. The aim of this PhD then is to establish the energetic costs of growing and maintaining testes and the production of spermatozoa. Most of the work will be conducted on birds. Birds show striking seasonal patterns of testes growth and regression, providing excellent opportunities for estimating the costs of testis growth and maintenance. The PhD will provide training in experimental design and light microscopy. The PhD is part of an ERC-funded grant to TRB. More details are available on request from Tim Birkhead (T.R.Birkhead@sheffield.ac.uk)

For more information about how to apply, or the application process, please contact Mrs S Carter (s.a.carter@sheffield.ac.uk).
To apply now go to: http://www.sheffield.ac.uk/postgraduate/online