Age-specific mortality costs of exposure to inbred Drosophila melanogaster in relation to longevity selection

This article address the hypotheses that selection for early- or late-life fitness changes patterns of reproductive behavior, that this behavior may be dependent on the genetic makeup of the females, and that patterns of male mortality are strongly dependent on the type of females to which they are exposed. Flies selected for late-life reproduction and their associated stocks selected for early reproduction were exposed to flies of the opposite sex from either the same stock or a highly inbred stock. Males of both long- and short-lived stocks showed an increase in early mortality when exposed to inbred females. In addition, when males were exposed to inbred females early in life they showed a lower age-specific mortality rate late in life than males exposed to females from their own stock. Interestingly, females exposed to inbred males showed a significant reduction in mean longevity. Analysis of age-specific mortality revealed that this reduction was brought about as a result of increased early mortality. Interpretation of the results from an analysis of mean longevity not only fails to identify important information--as shown from a demographic analysis of age-specific mortality--but also presents a misleading description of mortality costs.