Influence of Temperature Variations on Rate of Development in Insects: Analysis of Case Studies from Entomological Literature

Abstract

Case studies on development-time data collected at constant and varying temperatures in a number of insects have been analyzed in a comparative manner to investigate the effects of temperature variations on rate of development. Sources of experimental errors are many and are not always adequately controlled. For statistical analysis, the more common problems include the assumption of a linear relationship between temperature and development rate over the whole temperature range and extrapolation or subjective vertical cutoff of the rate function in rate summation for varying temperatures. Development-time data of 26 species were selected for the analysis. For each species, the expected development time under each varying temperature regime was estimated by integrating constant temperature development rates over the 24-h varying temperature cycle. These estimates were then compared with the development times observed under the corresponding varying temperature regimes, and the significance of the differences was evaluated. The results as a whole suggest that the differences in development times between constant and varying temperatures could usually be accounted for by the effect of rate summation based on the curvilinear relationship between temperature and rate of development. The possible physiological mechanisms that act in addition to the rate-summation effect are briefly discussed. Finally, the need for more extensive and detailed investigations in this area of study is indicated.