The physiology and biochemistry of cold tolerance in arctic insects

Nine species of insects from three different geographical regions of Canada were examined for freezing tolerance, supercooling capacity, water content and changes in biochemical characteristics during acclimation to subzero temperatures. Six species proved to be freezing tolerant, the remaining three freezing susceptible. The majority of species in each category conformed to the generally recognized profiles of overwintering response. There were enough specific variations within each category, however, to indicate that cold tolerance mechanisms have evolved independently on a number of different occassions. Specific physiological and biochemical anomalies in these insects were discussed.