When Darwin first proposed sexual selection theory he suggested two mechanisms: competition among males and choice by females. There is no doubt that these mechanisms are immensely important, but their mirror images have been largely underappreciated so far. In fact, males choose as well and females compete. Males choose based on female quality, often selecting mating partners that are more fecund. But male choice is also associated with changes in the sex ratio of a population and males can be choosy when they are rare. Furthermore, males sometimes invest heavily into reproduction and that too can be associated with male choice. That females compete with another, although less often with open aggression, is another understudied phenomenon. Finally, we now know that females are often ornamented, but are these ornaments under sexual selection by males? This book tries to review what we know and point to what we don’t know while pointing out the connections between male mate choice and female competition for a more complete view of sexual selection.
Operational sex ratio does not influence the evolution of male mate choice in the Indian meal moth