title: Effect of extrinsic mortality on the evolution of senescence in guppies.
abstract: Classical theories for the evolution of senescence predict that organisms that experience low mortality rates attributable to external factors, such as disease or predation, will evolve a later onset of senescence. Here we use patterns of senescence in guppies derived from natural populations that differ in mortality risk to evaluate the generality of these predictions. We have previously found that populations experiencing higher mortality rates evolve earlier maturity and invest more in reproduction, as predicted by evolutionary theory. We report here that these same populations do not have an earlier onset of senescence with respect to either mortality or reproduction but do with respect to swimming performance, which assesses neuromuscular function. This mosaic pattern of senescence challenges the generality of the association between decreased extrinsic mortality and delayed senescence and invites consideration of more derived theories for the evolution of senescence.
authors.affiliation: Department of Biology, University of California, Riverside, California 92521, USA. david.reznick@ucr.edu
authors.forename: David N
authors.initials: DN
authors.lastname: Reznick
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Bryant
authors.forename: Derek
authors.initials: D
authors.lastname: Roff
authors.forename: Cameron K
authors.initials: CK
authors.lastname: Ghalambor
authors.forename: Dionna E
authors.initials: DE
authors.lastname: Ghalambor
mesh_terms: D000375:Aging / Q000502:physiology*; D000818:Animals; D005075:Biological Evolution; D001824:Body Constitution; D005260:Female; D005399:Fishes / Q000502:physiology*; D020387:Food Chain; D008098:Litter Size; D008136:Longevity / Q000502:physiology*; D008297:Male; D008954:Models, Biological; D011336:Probability; D012098:Reproduction / Q000502:physiology; D015996:Survival Rate; D013550:Swimming / Q000502:physiology; D013997:Time Factors