THE DARWIN-FISHER THEORY OF SEXUAL SELECTION IN MONOGAMOUS BIRDS

摘要: Males of monogamous birds often show secondary sexual traits that are conspicuous but considerably less extreme than those polygynous species. We develop a quantitative-genetic model for the joint evolution male trait, female mating preference, and breeding date, following theory proposed by Darwin Fisher. Good nutritional condition is postulated to cause females breed early have high fecundity. The most-preferred males mated early-breeding receive sexual-selection advantage from females' greater reproductive success. Results decrease survival can evolve suggest extent maladaptive greatly limited relative what possible in system two reasons. First, absence direct fitness effects mate choice on female, equilibria trait preference form curve whose shape shows maximum strength selection (and hence potential evolution) constrained. Under certain conditions, segment equilibrium may become unstable, leading alternative stable states trait. Second, parental care will favor preferences males. also find appear emphasized A review literature suggests assumptions Darwin-Fisher mechanism be met other mechanisms reinforce it producing additional components selection.