Insects in variable environments: thermal performance, standard metabolic rate, and strategies to escape its limitations

Temperature is a decisive factor for life on earth because chemical reaction speed increases with temperature. Insects are ectothermic at rest, and in this way are subject to the direct influence of environmental temperature on growth, development and reproduction. Thermal performance curves (thermal reaction norms) describe the change of metabolism and development speed with temperature, which increase with temperature differently in different species and developmental stages. This review summarizes the main principles and findings on these relationships in insects, provides hints on how to measure respiratory performance curves, and reports different attempts to describe them mathematically. In addition, it summarizes some behavioral and physiological strategies insects have developed to escape the limitations of their thermal performance relationships.