Authors: Lesley A Alton, Teresa Kutz, Candice L Bywater, Emily Lombardi, Fiona E Cockerell, Sean Layh, Hugh Winwood-Smith, Pieter A Arnold, Julian E Beaman, Greg M Walter, Keyne Monro, Christen K Mirth, Carla M Sgrò, and Craig R White

Published in: Philosophical Transactions of the Royal Society B: Biological Sciences

Abstract

Metabolic cold adaptation, or Krogh’s rule, is the controversial hypothesis that predicts a monotonically negative relationship between metabolic rate and environmental temperature for ectotherms living along thermal clines measured at a common temperature.

Macrophysiological patterns consistent with Krogh’s rule are not always evident in nature, and experimentally evolved responses to temperature have failed to replicate such patterns. Hence, temperature may not be the sole driver of observed variation in metabolic rate.

We tested the hypothesis that temperature, as a driver of energy demand, interacts with nutrition, a driver of energy supply, to shape the evolution of metabolic rate to produce a pattern resembling Krogh’s rule. To do this, we evolved replicate lines of Drosophila melanogaster at 18, 25 or 28°C on control, low-calorie or low-protein diets.

Contrary to our prediction, we observed no effect of nutrition, alone or interacting with temperature, on adult female and male metabolic rates. Moreover, support for Krogh’s rule was only in females at lower temperatures.

We, therefore, hypothesize that observed variation in metabolic rate along environmental clines arises from the metabolic consequences of environment-specific life-history optimization, rather than because of the direct effect of temperature on metabolic rate.

Citation

Alton LA, Kutz T, Bywater CL, Lombardi E, Cockerell FE, Layh S, Winwood-Smith H, Arnold PA, Beaman JE, Walter GM, Monro K, Mirth CK, Sgrò CM, White CR (2024) Temperature and nutrition do not interact to shape the evolution of metabolic rate. Philosophical Transactions of the Royal Society B: Biological Sciences PDF DOI