Khazaeli A A, Xiu L, Curtsinger J W
Department of Ecology, Evolution, and Behavior, University of Minnesota, USA.
J Gerontol A Biol Sci Med Sci. 1995 Sep;50(5):B262-9. doi: 10.1093/gerona/50a.5.b262.
Mortality rates decelerate at older ages in experimental populations of Drosophila. It is unclear whether this reflects a real slow-down in the aging process, or an artifact of declining density. Mortality was studied in age-synchronized cohorts of four inbred lines at three initial densities that varied 10-fold. A total of 70,000 flies of both sexes were studied. There were large line x density, line, and sex effects, but no systematic relationship between density and life span was detected. Mortality curves level off at older ages in 23 out of 24 sex-genotype combinations, irrespective of initial cohort density. Density has only second-order effects on the pattern of oldest-old mortality over the range of densities studied here. The dramatic departure from Gompertz-type mortality dynamics at older ages is not an artifact of declining density in Drosophila.
在果蝇实验种群中，死亡率在老年阶段会下降。目前尚不清楚这是反映了衰老过程的真正减缓，还是密度下降的假象。在四个近交系的年龄同步队列中，研究了三种初始密度相差10倍的死亡率情况。共研究了7万只雌雄果蝇。存在显著的品系×密度、品系和性别效应，但未检测到密度与寿命之间的系统关系。在24种性别-基因型组合中的23种中，无论初始队列密度如何，死亡率曲线在老年阶段都会趋于平稳。在此研究的密度范围内，密度对最老龄死亡率模式只有二阶效应。果蝇老年阶段与冈珀茨型死亡率动态的显著差异并非密度下降的假象。
