Heat-induced hormesis in longevity as correlated responses to thermal-stress selection in Drosophila buzzatii

FEDERICO H GÓMEZ, CARLOS I BERTOLI, PABLO SAMBUCETTI, ALEJANDRA C SCANNAPIECO, FABIAN M NORRY

JOURNAL OF THERMAL BIOLOGY

PERGAMON-ELSEVIER SCIENCE LTD

Lugar: Amsterdam; Año: 2008 p. 17 - 22

0306-4565

Hormesis in longevity is a very widespread phenomenon across the animal kingdom. It takes place when longevity is improved as an indirect effect of mild stress. We explored some possible evolutionary trajectories of hormesis in longevity by testing experimental evolution in artificially selected lines of Drosophila buzzatii. The lines were bi-directionally selected for either knockdown resistance to heat stress (K-, K+) or chill-coma recovery (CCR-, CCR+, the sign indicating selection for decreased and increased tolerance, respectively). All K and CCR lines successfully diverged by termal-stress selection. The heat-inducible hormesis in longevity was substantial in both K- and CCR- females, whereas no hormesis was apparent for females in CCR+, K+ and control lines. Among-line differences in longevity of non-heat-treated females dissapeared after a heat-hardening treatment. Hormesis effects on the demografic senescence rate were consistently higher in the shorter-lived than in the longer-lived lines. Hormesis is an adaptive response, as its magnitude can evolutionary increase in populations artificially selected for stress-suceptibility.