Department of Ecology, Evolution, & Behavior, University of Minnesota - Twin Cities, 1987 Upper Buford Circle, St. Paul, MN, 55108, USA.
Biogerontology. 2020 Dec;21(6):721-730. doi: 10.1007/s10522-020-09889-5. Epub 2020 Jul 7.
There are two life history landmarks that can be used to define the terminal period in individual Drosophila melanogaster females: the cessation of daily oviposition, which defines the start of the retired stage, and final oviposition, which defines the start of post-ovipository survival. The terminal period is a substantial component of D. melanogaster life history. Analysis of published data on the daily fecundity and survival of 3971 individually maintained, mated female flies reveals that the terminal period is far more variable within populations than other life history components, including total adult life span. It has been reported that there is a negative correlation between fecundity and duration of the terminal state in recently collected wild stocks. Here I show that the negative correlation occurs in multiple inbred and outbred lab-adapted populations as well. In terms of proportion of adult life, lower fecundity flies spend on average twice as much time in the terminal stage as higher fecundity flies from the same population. Both high and low fecundity flies experience end-of-life plateaus in mortality, with the former exhibiting higher plateau levels. The negative correlation between fecundity and terminal survival is of sufficient magnitude to create heterogeneity among the oldest old: the final 10% of survivors are predominately flies with a history of high fecundity, but about one in five is a low fecundity fly with long terminal stage.
每日产卵的停止，这定义了退休阶段的开始，以及最后一次产卵，这定义了产卵后生存的开始。终末期是黑腹果蝇生命史的重要组成部分。对 3971 只单独饲养、交配的雌性果蝇的每日产卵量和存活率的已发表数据进行分析表明，与其他生命史组成部分（包括成虫总寿命）相比，终末期在种群内的变异性要大得多。据报道，在最近收集的野生种群中，产卵量与终末期持续时间呈负相关。在这里，我表明这种负相关也发生在多个近交和远交实验室适应的种群中。就成虫寿命的比例而言，与同一群体中产卵量较高的雌蝇相比，产卵量较低的雌蝇平均在终末期花费的时间要多出一倍。高产卵量和低产卵量的果蝇在死亡时都会经历生命末期的平台期，前者的平台水平更高。产卵量和终末期存活率之间的负相关具有足够大的强度，可以在最老的个体中产生异质性：最后的 10%的幸存者主要是具有高产卵量历史的果蝇，但其中约五分之一是产卵量低但终末期长的果蝇。
