The evolution of sex differences in mate-attracting signalling

Question: To attract mates, many insects dance, have conspicuous plumage, call vocally, and emit signals such as pheromones. Mate-attracting signals are produced predominantly by males in some species and by females in others. We ask, which sex should evolve to produce mate-attracting signals? Method: We used a quantitative genetic model for the signal-sending and signal-receiving efforts of the two sexes. Mate-finding success is assumed to be a product of power functions of the signal sender's and signal receiver's investments. Results: If mate-finding success strongly depends on the investments of both senders and receivers, only one sex evolves to send the signals; otherwise, both sexes evolve to emit signals. Males evolve to assume the role that more strongly affects mate-finding success, and to engage in mate-finding activities with more investments than females.