Studies of the evolutionary genetics of sexual behaviour have undergone major changes in the last few decades (see Chapters 2 and 10). There have been many great successes in identifying and analysing the influence of single genes, but also an increasing realisation that sexual coevolution and social interactions can influence the evolution of sexual communication systems in unpredictable ways.

When I was a zoology student at the University of Edinburgh in the early 1980s, studying the evolutionary genetics of behaviour seemed an interesting and reasonably tractable project. Lectures in genetics, particularly by Trudy Mackay and Doug Falconer, had impressed upon us that traits like morphology or milk yield in cows were influenced by too many genes to ever identify, so a statistical approach to partitioning genetic and environmental effects (heritability) was necessary. Lectures on the evolution of behaviour, particularly from Linda Partridge and Aubrey Manning, had shown how the genetic control of behaviour had itself evolved, and that the amount of genetic variation for traits was a key to understanding behavioural evolution. So, for example, females exert sexual selection on males by choosing mates based upon traits which evolve in a manner equivalent to milk yield in cows. These traits are correlated with fitness (for indirect genetic benefits, or ‘good genes’). However, mutual coevolution between male and female traits was particularly important.