EVAPORATIVE COOLING IN INSECTS

Abstract Insects commonly use behavior to avoid the heat stress and consequent water loss of hot environments. It has been assumed by many to be impossible or impractical for insects to employ evaporative cooling. Despite this assumption, there have been many instances, historically and recently where insects are reported to survive otherwise lethal temperatures by evaporating water. The site of evaporation may be internal, as a consequence of increased ventilation, or on the body surface where water is exuded from several different sites in different species. Some species must rely on their body water stores while others can obtain water abundantly from plants. There is a lower limit of body size at which evaporative water loss becomes ineffective. This limit is lower than may have been previously thought.