Data from: Patterns of male fitness conform to predictions of evolutionary models of late-life

We studied lifetime male virility, a male fitness component, in five populations of Drosophila melanogaster. Virility was measured as the number of females, out of eight total, that a male could fertilize in 24 hours. Individual males were measured at weekly intervals until they died. Virility declined in an approximately linear fashion for the first three weeks of adult life. It then stayed low but relatively constant for another three weeks, exhibiting a clear plateau. These observations are consistent with the evolutionary theories of late-life.The results were not consistent with a simple heterogeneity theory of late-life. This is the first demonstration of a late-life plateau for a male fitness component. We also found that the virility of males that were within seven days of death was significantly lower than similarly aged males that were not about to die. This rapid deterioration of virility prior to death, or death spiral, is similar to a decline in fecundity that we had previously documented.我们以5个黑腹果蝇（Drosophila melanogaster）种群为研究对象，探讨了作为雄性适合度组分的终生雄性生殖力。该生殖力以单只雄性在24小时内可使8只雌性成功受精的数量作为衡量指标。我们每周对单只雄性果蝇进行一次检测，直至其死亡。在成虫期的前3周，雄性生殖力大致呈线性下降趋势；随后的3周内，生殖力维持在较低水平且相对稳定，呈现出清晰的平台期。上述观测结果与衰老晚期的进化理论相符，但该结果并不支持衰老晚期的简单异质性理论。本研究首次证实了雄性适合度组分存在衰老晚期平台期。我们还发现，距死亡不足7天的雄性果蝇，其生殖力显著低于同龄且暂无死亡风险的雄性个体。这种死亡前生殖力的快速衰退（即死亡螺旋），与我们此前记录到的繁殖力下降现象高度相似。