Here we report one of the first investigations of evolvability of lifespan and reproduction in metazoans, examining both extrinsic and intrinsic factors. We tested effects on senescence of an environmental variable (simulated lake hydroperiod, the length of time an aquatic habitat is inundated), female reproductive physiology (asexual females that reproduce by ameiosis, vs. sexual females reproducing by meiosis), and time in a benign culture environment (minimal, if any, external mortality factors). To do this we established chemostat cultures of the rotifer Brachionus plicatilis s.s., and maintained the cultures for 385 days. Hydroperiod alone, or in interaction with the effects of reproductive physiology and time in the benign environment, had no significant effect on the rate of aging. Yet combining animals from both ephemeral and permanent hydroperiods revealed a 26% increase in asexual female lifespan across seasons (23% decrease in the rate of aging) and a 56% increase in asexual fecundity, suggesting that maintenance in benign laboratory conditions leads to slower aging. The relative stasis of traits for sexual in contrast to asexual females implies a role of reproductive physiology on evolvability. In addition we found a positive correlation between fecundity and lifespan, suggesting an absence of trade-offs in these life history traits in the benign laboratory environment.

中文翻译：

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良性环境中无性雌性和有性雌性寿命和生育力的差异进化

在这里，我们报告了对后生动物寿命和繁殖进化性的初步调查之一，检查了外在和内在因素。我们测试了环境变量（模拟湖水周期、水生栖息地被淹没的时间长度）、雌性生殖生理学（通过减数分裂繁殖的无性雌性与通过减数分裂繁殖的有性雌性）和良性时间的影响。培养环境（最小的，如果有的话，外部死亡因素）。为此，我们建立了皱褶轮虫 ss 的恒化培养物，并将培养物保持 385 天。单独使用Hydroperiod，或与良性环境中生殖生理和时间的影响相互作用，对衰老速度没有显着影响。然而，将来自短暂和永久水期的动物结合起来显示，无性雌性跨季节的寿命增加了 26%（衰老率降低了 23%），无性繁殖力增加了 56%，这表明在良性实验室条件下维持会导致衰老减慢. 与无性雌性相比，性特征的相对停滞意味着生殖生理学对可进化性的作用。此外，我们发现繁殖力和寿命之间呈正相关，表明在良性实验室环境中这些生活史特征不存在权衡。与无性雌性相比，性特征的相对停滞意味着生殖生理学对可进化性的作用。此外，我们发现繁殖力和寿命之间呈正相关，表明在良性实验室环境中这些生活史特征不存在权衡。与无性雌性相比，性特征的相对停滞意味着生殖生理学对可进化性的作用。此外，我们发现繁殖力和寿命之间呈正相关，表明在良性实验室环境中这些生活史特征不存在权衡。