Carey J R, Liedo P
Department of Entomology, University of California, Davis 95616, USA.
Exp Gerontol. 1995 May-Aug;30(3-4):315-25. doi: 10.1016/0531-5565(94)00041-z.
Life table aging rate (LAR) is defined as the age-specific rate of mortality change with age and corresponds to the first derivative or slope of the mortality schedule at each age. We computed the sex-specific LARs for 167 Medfly cohorts, containing a total of approximately 600,000 individuals of each sex. We found that: (a) the LAR is not constant for either sex; at the youngest ages, mortality changes by approximately 1.4-fold daily, whereas at the older ages (>30 days), mortality levels off and decreases; (b) female LAR is higher than male LAR from 0 to 12 days, at which time the rates cross over and male LAR is higher than female LAR; however, at about 30 days, both male and female LARs are less than or equal to unity; (c) mortality in each of the 167 cohorts leveled off for both sexes. The average age for this leveling off was around 23 days for females and 31 days for males; and (d) the mortality rate at the age of leveling off was approximately 1.4-fold higher in males than in females--0.13/day for females and 0.19/day for males. Implications of these findings are briefly discusses, including the use of summary measures of senescence, the arbitrariness of selecting the age of senescence onset, and test of hypotheses concerned with explanations of mortality patterns such as leveling off at older ages.
生命表老化率（LAR）被定义为特定年龄的死亡率随年龄变化的速率，对应于每个年龄死亡率曲线的一阶导数或斜率。我们计算了167个地中海实蝇队列的性别特异性LAR，每个性别总共约有600,000个个体。我们发现：（a）无论男性还是女性，LAR都不是恒定的；在最年轻的年龄段，死亡率每天变化约1.4倍，而在较年长的年龄段（>30天），死亡率趋于平稳并下降；（b）在0至12天，雌性LAR高于雄性LAR，此时两者速率交叉，雄性LAR高于雌性LAR；然而，在大约30天时，雄性和雌性LAR均小于或等于1；（c）167个队列中两性的死亡率均趋于平稳。这种平稳的平均年龄在雌性中约为23天，在雄性中约为31天；（d）平稳年龄时的死亡率，雄性比雌性高约1.4倍——雌性为0.13/天，雄性为0.19/天。简要讨论了这些发现的意义，包括衰老的汇总测量方法的使用、衰老起始年龄选择的随意性，以及与死亡率模式解释相关的假设检验，如在较年长时趋于平稳。
