title: Metabolic and functional characterization of effects of developmental temperature in Drosophila melanogaster.
abstract: The ability of ectotherms to respond to changes in their thermal environment through plastic mechanisms is central to their adaptive capability. However, we still lack knowledge on the physiological and functional responses by which ectotherms acclimate to temperatures during development, and in particular, how physiological stress at extreme temperatures may counteract beneficial acclimation responses at benign temperatures. We exposed Drosophila melanogaster to 10 developmental temperatures covering their entire permissible temperature range. We obtained metabolic profiles and reaction norms for several functional traits: egg-to-adult viability, developmental time, and heat and cold tolerance. Females were more heat tolerant than males, whereas no sexual dimorphism was found in cold tolerance. A group of metabolites, mainly free amino acids, had linear reaction norms. Several energy-carrying molecules, as well as some sugars, showed distinct inverted U-shaped norms of reaction across the thermal range, resulting in a positive correlation between metabolite intensities and egg-to-adult viability. At extreme temperatures, low levels of these metabolites were interpreted as a response characteristic of costs of homeostatic perturbations. Our results provide novel insights into a range of metabolites reported to be central for the acclimation response and suggest several new candidate metabolites. Low and high temperatures result in different adaptive physiological responses, but they also have commonalities likely to be a result of the failure to compensate for the physiological stress. We suggest that the regulation of metabolites that are tightly connected to the performance curve is important for the ability of ectotherms to cope with variation in temperature.
authors.affiliation: Department of Bioscience, Aarhus University, Aarhus C, Denmark.
authors.forename: Mads F
authors.initials: MF
authors.lastname: Schou
authors.affiliation: Department of Bioscience, Aarhus University, Aarhus C, Denmark.|Department of Chemistry and Bioscience, Aalborg University, Aalborg East, Denmark.
authors.forename: Torsten N
authors.initials: TN
authors.lastname: Kristensen
authors.affiliation: The Swedish NMR-Centre, University of Gothenburg, Gothenburg, Sweden; and.
authors.forename: Anders
authors.initials: A
authors.lastname: Pedersen
authors.affiliation: The Swedish NMR-Centre, University of Gothenburg, Gothenburg, Sweden; and.
authors.forename: B Göran
authors.initials: BG
authors.lastname: Karlsson
authors.affiliation: Department of Bioscience, Aarhus University, Aarhus C, Denmark.
authors.forename: Volker
authors.initials: V
authors.lastname: Loeschcke
authors.affiliation: Department of Cellular and Molecular Medicine, University of Copenhagen, Copenhagen N, Denmark malmendal@gmail.com.
authors.forename: Anders
authors.initials: A
authors.lastname: Malmendal
mesh_terms: D000375:Aging / Q000502:physiology*; D000818:Animals; D001833:Body Temperature Regulation / Q000502:physiology*; D029721:Drosophila Proteins / Q000378:metabolism*; D004331:Drosophila melanogaster / Q000502:physiology*; D005260:Female; D018507:Gene Expression Regulation, Developmental / Q000502:physiology; D018869:Heat-Shock Response / Q000502:physiology*; D008297:Male; D055442:Metabolome / Q000502:physiology; D012727:Sex Characteristics; D000071436:Thermotolerance / Q000502:physiology*
chemical_list: D029721:Drosophila Proteins
keywords: developmental acclimation; environmental stress; extreme temperatures; nuclear magnetic resonance metabolomics; plastic responses; sexual dimorphism; thermal performance curve; thermal resistance