© 1992 by The Society for Integrative and Comparative Biology
Biophysical Ecology and Heat Exchange in Insects1
Department of Entomology, Cook College, Rutgers University New Brunswick, New Jersey 08903
When used with observations of behavior and physiology of animals in known microclimates, a biophysical approach is a powerful tool for predicting body temperatures of insects. For ectothermic insects, solution of the energy budget equation and use of operative temperature models have been used to determine the range of temperatures which an insect can exhibit in a given environment. Knowledge of body temperature has allowed predictions of when important behaviors arepossible in the field, thereby directly relating biophysical models to fitness parameters of animals. A proper understanding of the physiological mechanism(s) controlling heat exchange is prerequisite to application and interpretation of information obtained using biophysical techniques. For endothermic insects, physiological regulation of heat exchange forces a more complicated analysis. Evaluation of thoracic heat exchange alone (aside from indicating whether insects are regulating Tth) is of little utility for either quantifying total heat exchange, or evaluating thermoregulatory mechanisms without further information. Further studies of biophysics and physiology of endothermic insects during flight are needed to correct these deficiencies. Application of biophysical techniques has allowed predictions of behavior of flying insects based onprinciples of heat exchange which cannot be examined directly. Analyses of endothermy of restinghoneybee swarms and hives indicate that these "superorganisms" regulate temperature rather precisely over a remarkable range of environmental temperature using mechanisms equivalent to thoseused by resting endothermic vertebrates.