Disentangling the Consequences of Growth Temperature and Adult Acclimation Temperature on Starvation and Thermal Tolerance in the Red Flour Beetle

Temperature affects most aspects of animal life, and impacts particularly strongly on ectotherms. We studied the combined effects of growth temperature and adult acclimation temperature on starvation tolerance, cold tolerance, and heat tolerance in the red flour beetle. A lower adult acclimation temperature enhanced starvation tolerance and cold tolerance and impaired heat tolerance. This is an expected outcome of short-term plasticity and of the beneficial acclimation hypothesis. The higher growth temperature led to improved performance of all three measured traits: beetles raised under higher temperature tolerated starvation longer and showed better cold and heat tolerance. While this result fits well the rule “hotter is better”, it is nonetheless surprising that the same temperature had opposite effects when experienced by juveniles and adults (i.e., the effect of the warm temperature on cold tolerance). We emphasize the importance of separating between the juvenile growth temperature (developmental plasticity) and adult temperature (acclimation), as they can have opposite effects on adult performance.