MALE PARENTAL CARE, DIFFERENTIAL PARENTAL INVESTMENT BY FEMALES AND SEXUAL SELECTION

Males play a variable parental role in reproduction, ranging from no m ale parental care to extensive male care. Females may acquire either d irect or indirect fitness benefits from their mate choice, and direct fitness benefits include male parental care. Theoreticians have tradit ionally emphasized direct fitness benefits to females in species with extensive male parental care. We review the literature and show extens ive variation in the patterns of male care, related to the attractiven ess of males to females. At one extreme of this continuum, females inv est differentially in parental care, investing more when paired with a ttractive males. The costs of female parental care and other aspects o f parental investment may be balanced by benefits in terms of more att ractive sons and/or more viable offspring. At the other extreme, in sp ecies with extensive direct fitness benefits, males with preferred sex ual phenotypes provide the largest relative share of parental care. A comparative study of birds revealed that the extent of the differentia l female parental investment was directly related to the frequency of extra-pair paternity. Since extra-pair paternity may arise mainly as a consequence of female choice for indirect fitness benefits, this resu lt supports our prediction that differential parental investment is pr evalent in species where females benefit indirectly from their mate ch oice. The consequences for sexual selection theory of these patterns o f male care in relation to male attractiveness are emphasized. (C) 199 8 The Association for the Study of Animal Behaviour.