the evolution of senescence and post-reproductive lifespan in guppies (poecilia reticulata)孔雀鱼的衰老和寿命后生育期的进化(poecilia试).pdf

PLoS BIOLOGY The Evolution of Senescence and Post-Reproductive Lifespan in Guppies (Poecilia reticulata) David Reznick1*, Michael Bryant1,2, Donna Holmes3 1 Department of Biology and Center for Conservation Biology, University of California Riverside, Riverside, California, United States of America, 2 School of Critical Studies, California Institute of the Arts, Valencia, California, United States of America, 3 Department of Biological Sciences, University of Idaho, Moscow, Idaho, United States of America The study of post-reproductive lifespan has been of interest primarily with regard to the extended post-menopausal lifespan seen in humans. This unusual feature of human demography has been hypothesized to have evolved because of the ‘‘grandmother’’ effect, or the contributions that post-reproductive females make to the fitness of their children and grandchildren. While some correlative analyses of human populations support this hypothesis, few formal, experimental studies have addressed the evolution of post-reproductive lifespan. As part of an ongoing study of life history evolution in guppies, we compared lifespans of individual guppies derived from populations that differ in their extrinsic mortality rates. Some of these populations co-occur with predators that increase mortality rate, whereas other nearby populations above barrier waterfalls are relatively free from predation. Theory predicts that such differences in extrinsic mortality will select for differences in the age at maturity, allocation of resources to reproduction, and patterns of senescence, including reproductive declines. As part of our evaluation of these predictions, we quantified differences among populations in post-reproductive lifespan. We present here the first fo