Temperature induces changes in Drosophila energy stores

Peter Klepsatel,David Wildridge,Martina Gáliková

doi:10.1038/s41598-019-41754-5

Peter Klepsatel, David Wildridge + Show 1 more

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https://doi.org/10.1038/s41598-019-41754-5

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Abstract

Temperature has a profound impact on animal physiology. In this study, we examined the effect of ambient temperature on the energy stores of the model organism Drosophila melanogaster. By exposing adult males to 11 temperatures between 13 °C and 33 °C, we found that temperature significantly affects the amount of energy reserves. Whereas flies increase their fat stores at intermediate temperatures, exposure to temperatures below 15 °C or above 27 °C causes a reduction of fat reserves. Moreover, we found that glycogen stores followed a similar trend, although not so pronounced. To elucidate the underlying mechanism of these changes, we compared the temperature dependence of food consumption and metabolic rate. This analysis revealed that food intake and metabolic rate scale with temperature equally, suggesting that the temperature-induced changes in energy reserves are probably not caused by a mismatch between these two traits. Finally, we assessed the effect of temperature on starvation resistance. We found that starvation survival is a negative exponential function of temperature; however we did not find any clear evidence that implies the relative starvation resistance is compromised at non-optimal temperatures. Our results indicate that whilst optimal temperatures can promote accumulation of energy reserves, exposure to non-optimal temperatures reduces Drosophila energy stores.

Highlights

Temperature affects organisms at all levels of biological organization, from macromolecules to ecosystems[1,2]
Metabolism is the sum of all reactions that occur in an organism and provides energy to perform vital processes and to maintain organismal and cellular homeostasis[6]
Our study shows that the effect of temperature on energy stores, fat stores in particular, in adult Drosophila males is best described by a quadratic function with the maximum at intermediate temperatures

Summary

Introduction

Temperature affects organisms at all levels of biological organization, from macromolecules to ecosystems[1,2] These effects are usually explained by dependency of rates of biochemical reactions and biological processes on ambient temperature[3]. We further systematically investigated the effect of temperature on energy stores by examining temperature-induced changes in Drosophila fat and glycogen reserves over the range of 20 °C (13 °C–33 °C), covering the natural thermal range of this species[26]. At non-optimal conditions (stressful low and high temperatures), additional energy costs or decreased energy acquisition might lead to reduction of energy stores[16] To test this hypothesis, we first examined temperature-induced changes in energy stores in Drosophila males at eleven temperatures (four-day old males were exposed to different temperatures for eight days). We examined the relationship between ambient temperature, metabolic rate (energy expenditure) and food intake (energy acquisition)

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