|65. University Of Liverpool Applied Mathematics Staff |
Parker, G.A., Chubb, J.C., ball, M.A, and Roberts, G.N., Evolution of Complex life cycles in Parker G.A., ball, M.A., Stockley, P., and Gage, M.J.G.
Dr M.A. Ball Research interests
(i) mathematical biology
(i) superplayer coalitions in game theory.
In (i) I have been investigating sperm competition games Professor Geoff. Parker of the Biological Sciences Department. For example, in certain species, when a female fish is about to spawn, several males gather around her. When she lays her eggs in the water, the males ejaculate their sperm into the water simultaneously. We investigate how the number of sperm and their mass vary with the number of males present, using ESS theory. We have also been investigating male ejaculation strategies when males mate$ but females may copulate once or twice only for a given set of eggs. The male has to assess whether a female is a virgin who will only mate once or$ will mate again or if she has already mated once. Interesting effects occur when the male has some partial information but the frequency of double mating is low. Recent work has clarified the random-roles and constant -roles models and the importance of sperm limitation. At present Geoff and I have recently published a paper on the effect of female preference, using a model where a female mates twice and can favour, at a cost in terms of eggs produced,a particular type of male. The behaviour of helminth parasites is very unusual as they often live in several different species as hosts. We have just published in