Sexual conflict, life span, and aging

Abstract

The potential for sexual conflict to influence the evolution of life span and aging has been recognized for more than a decade, and recent work also suggests that variation in life span and aging can influence sexually antagonistic coevolution. However, empirical exploration of these ideas is only beginning. Here, we provide an overview of the ideas and evidence linking inter- and intralocus sexual conflicts with life span and aging. We aim to clarify the conceptual basis of this research program, examine the current state of knowledge, and suggest key questions for further investigation.

Figure 1.

In a “typical” mating system involving stronger sexual competition among males and greater investment in offspring among females, the sexes tend to encounter different “opportunity landscapes” that generate sex-specific selection on longevity and aging rate. (A) Females can gain fitness only in relatively small increments (small apples), by accumulating resources and converting those resources into offspring. In contrast, males have greater opportunity for large, short-term fitness gain (large apples) through mating. (B) Thus, for males, large, short-term investments in reproduction (including strategies that involve high risk of injury or death) may be favored by selection because such investments may result in large fitness payoffs. In contrast, females cannot gain equally large short-term fitness payoffs and may therefore be selected to pursue relatively safe, long-term strategies involving greater risk avoidance and larger investment in somatic maintenance.