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 beha vior may be dependent on the genetic makeup of the females, and that p atterns of male mortality are strongly dependent on the type of female s to which they are exposed. Flies selected for late-life reproduction and their associated stocks selected for early reproduction were expo sed to flies of the opposite sex from either the same stock or a highl y inbred stock. Males of both long- and short-lived stocks showed an i ncrease 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 t o females from their own stock. Interestingly, females exposed to inbr ed 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 resul ts from an analysis of mean longevity not only fails to identify impor tant information-as shown from a demographic analysis of age-specific mortality-but also presents a misleading description of mortality cost s.