Intermediate induction of germline apoptosis maintains fertility and progeny fitness during temperature stress

Organisms must be able to maintain the ability to produce high quality offspring despite experiencing stressful conditions. It is unknown how C. elegans maintain the ability to produce offspring during moderate temperature stress just below the range of temperature that cause sterility. We evaluated apoptosis, fertility, and several progeny fitness metrics in no-apoptosis, high-apoptosis mutants, and in wild strains that varied in their fertility level during moderate temperature stress to understand if apoptosis is a strategy C. elegans use to maintain the ability to produce offspring during a moderate temperature stress. We found that apoptosis mutants were less fertile with less fit progeny compared to wild type under a moderate temperature stress. Wild strains isolated from the environment showed variability in the increase in apoptosis, levels of fertility, and measurements of progeny fitness observed. We also found that an intermediate induction of apoptosis trended with higher fertility and progeny fitness in wild strains under a moderate temperature tress. These results suggest that apoptosis within an optimal range in the C. elegans germline is a strategy used to maintain the ability to produce high quality offspring despite experiencing a moderate temperature stress. Many species also have germline apoptosis, so apoptosis may be a strategy other species use to maintain their own fertility when experiencing stress conditions