Dr. Samuel J. Tazzyman

EPSRC PhD Plus 2010 Project: The mathematics of sexual signal evolution in a varying environment


Many of the most interesting characteristics in biology and medicine, such as intelligence, or susceptibility to disease, are influenced in a complex way by the interaction of both genetic and environmental factors. Living organisms universally respond to the environment as well as to their genes, creating phenotypic diversity within a population, upon which natural selection acts. One of the fundamental outstanding challenges in biology concerns how to relate the contributions of genes and environment (or nature and nurture) to one another within a single unified theory of evolutionary biology, explaining both how environmental sensitivity evolves, and how it in turn affects evolution.

The field of sexual selection in particular currently lacks a complete theory about genotype-environment interaction, with many existing models not considering traits to be affected by multiple genes. Sexual selection involves the transmission of signals by one sex (typically males) to another (females). These signals are often considered to be honest reflections of quality in some sense, and this is likely to be affected by the environment in which the signals were formed and are displayed. Thus there is scope for environmental effects in the form, size, honesty, and accuracy of the (male) signals, and in the (female) response to them. The study of environmental sensitivity in sexual selection could tell us a lot about the evolution of sensitivity in general, and in particular the importance of interactions between suites of environmentally sensitive traits.


Mathematical models for the evolution of sexual signalling use techniques such as difference equations and dynamical systems. There are also models for the evolution of environmental sensitivity in traits. The main work in this project will be to draw on the mathematical quantitative genetics techniques I have learnt and developed during my PhD in order to combine these two distinct bodies of work together to create a single mathematical framework that serves as a formal theory for the evolution of environmentally sensitive sexual signals and preferences.

The model produced by this project will be of high value for evolutionary theory, with ramifications for important issues such as speciation, and the evolutionary consequences of extreme environmental shifts (e.g. due to climate change), as well as for questions of interest in the field of sexual selection, such as the resolution of the lek paradox and the evolution of multiple signals. Fundamentally, the work is about the reliability of signals in noisy environments, and thus the findings are likely to be relevant for signalling theory in a much wider context. In addition, the project will involve the creation of novel mathematical techniques for dealing with evolutionary processes, such as the incorporation of information theory.

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