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Experimental evolution for generalists and specialists reveals multivariate genetic constraints on thermal reaction norms.

  • Berger D Department of Ecology and Genetics, Evolutionary Biology Centre, Uppsala University, Uppsala, Sweden; Institute for Evolutionary Biology and Environmental Studies, University of Zurich, Zurich, Switzerland.
  • Walters RJ
  • Blanckenhorn WU
  • 2014-07-22
Published in:
  • Journal of evolutionary biology. - 2014
adaptation
canalization
generalist
multivariate trade-off
performance curve
phenotypic plasticity
reaction norm
specialist
temperature tolerance
Adaptation, Physiological
Animals
Biological Evolution
Body Size
Diptera
Female
Genetic Fitness
Genetic Variation
Phenotype
Survival Rate
Temperature
English Theory predicts the emergence of generalists in variable environments and antagonistic pleiotropy to favour specialists in constant environments, but empirical data seldom support such generalist-specialist trade-offs. We selected for generalists and specialists in the dung fly Sepsis punctum (Diptera: Sepsidae) under conditions that we predicted would reveal antagonistic pleiotropy and multivariate trade-offs underlying thermal reaction norms for juvenile development. We performed replicated laboratory evolution using four treatments: adaptation at a hot (31 °C) or a cold (15 °C) temperature, or under regimes fluctuating between these temperatures, either within or between generations. After 20 generations, we assessed parental effects and genetic responses of thermal reaction norms for three correlated life-history traits: size at maturity, juvenile growth rate and juvenile survival. We find evidence for antagonistic pleiotropy for performance at hot and cold temperatures, and a temperature-mediated trade-off between juvenile survival and size at maturity, suggesting that trade-offs associated with environmental tolerance can arise via intensified evolutionary compromises between genetically correlated traits. However, despite this antagonistic pleiotropy, we found no support for the evolution of increased thermal tolerance breadth at the expense of reduced maximal performance, suggesting low genetic variance in the generalist-specialist dimension.
Language
  • English
Open access status
bronze
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Persistent URL
https://sonar.ch/global/documents/244732
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