title: Thermal tolerance and survival responses to scenarios of experimental climatic change: changing thermal variability reduces the heat and cold tolerance in a fly.
abstract: Climate change poses one of the greatest threats to biodiversity. Most analyses of the impacts have focused on changes in mean temperature, but increasing variance will also impact organisms and populations. We assessed the combined effects of the mean and the variance of temperature on thermal tolerances-i.e., critical thermal maxima, critical thermal minima, scope of thermal tolerance, and survival in Drosophila melanogaster. Our six experimental climatic scenarios were: constant mean with zero variance or constant variance or increasing variance; changing mean with zero variance or constant variance or increasing variance. Our key result was that environments with changing thermal variance reduce the scope of thermal tolerance and survival. Heat tolerance seems to be conserved, but cold tolerance decreases significantly with mean low as well as changing environmental temperatures. Flies acclimated to scenarios of changing variance-with either constant or changing mean temperatures-exhibited significantly lower survival rate. Our results imply that changing and constant variances would be just as important in future scenarios of climate change under greenhouse warming as increases in mean annual temperature. To develop more realistic predictions about the biological impacts of climate change, such interactions between the mean and variance of environmental temperature should be considered.
authors.affiliation: Departamento de Ecología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, 6513677, Santiago, Chile. fbozinovic@bio.puc.cl.|Center of Applied Ecology and Sustainability (CAPES), Pontificia Universidad Católica de Chile, 6513677, Santiago, Chile. fbozinovic@bio.puc.cl.
authors.forename: Francisco
authors.initials: F
authors.lastname: Bozinovic
authors.affiliation: Departamento de Ecología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, 6513677, Santiago, Chile.
authors.forename: Nadia R
authors.initials: NR
authors.lastname: Medina
authors.affiliation: Departamento de Ecología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, 6513677, Santiago, Chile.
authors.forename: José M
authors.initials: JM
authors.lastname: Alruiz
authors.affiliation: Departamento de Ecología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, 6513677, Santiago, Chile.|Center of Applied Ecology and Sustainability (CAPES), Pontificia Universidad Católica de Chile, 6513677, Santiago, Chile.
authors.forename: Grisel
authors.initials: G
authors.lastname: Cavieres
authors.affiliation: Center of Applied Ecology and Sustainability (CAPES), Pontificia Universidad Católica de Chile, 6513677, Santiago, Chile.|Departamento de Ciencias Ecológicas, Facultad de Ciencias, Universidad de Chile, Santiago, Chile.
authors.forename: Pablo
authors.initials: P
authors.lastname: Sabat
mesh_terms: D000064:Acclimatization / Q000502:physiology*; D000818:Animals; D057231:Climate Change; D003080:Cold Temperature; D004331:Drosophila melanogaster / Q000502:physiology*; D006358:Hot Temperature; D008297:Male
keywords: Critical thermal maxima and minima; Drosophila melanogaster; Experimental climate scenarios; Global warming; Scope of thermal tolerance; Survival; Temperature mean; Temperature variation