Sexual communication.

Sexual communication refers to the use of signals to promote or modulate sexual interaction. We suggest that these signals operate at three levels: (a) a primary level at which signals are used to increase the likelihood of sexual interaction between two individuals; (b) a secondary level at which signals inhibit inbreeding or facilitate outbreeding; and (c) a tertiary level at which signals allow selection among potential mates. Evidence is cited that the selective advantage of the primary, secondary and tertiary levels are, respectively, repair of DNA damage, masking of mutation, and selection for fitness in the mating partner. We illustrate how these advantageous processes are facilitated by sexual communication in bacteria, fungi, protozoa, insects, plants and vertebrates. Copyright 1997 Academic Press Limited.