6.6. Dealing with environmental extremes
The most obvious environmental variables that con- front an insect are seasonal fluctuations in temperature and humidity. The extremes of temperatures and humidities experienced by insects in their natural environments span the range of conditions encountered by terrestrial organisms, with only the suite of deep oceanic hydrothermic vent taxa encountering higher temperatures. For reasons of human interest in cryobiology (revivable preservation) the responses to extremes of cold and desiccation have been better studied than those to high temperatures alone.
The options available for avoidance of the extremes are behavioral avoidance, such as by burrowing into soil of a more equable temperature, migration (section 6.7), diapause (section 6.5), and in situ tolerance/ survival in a very altered physiological condition, the topic of the following sections.