Fig. 2. Effect of rapid cold-hardening on the freeze tolerance of (A) summer-acclimatized larvae and (B) adults of the Antarctic midge, Belgica antarctica. Cultures were maintained at 4°C prior to exposure to the indicated temperatures. ^* denotes a significant (P<0.05) difference in survival between groups directly exposed to -10°C and those that were first held at -5°C for 1 h prior to the -10°C exposure. Values are means ± s.e.m. based on six replicates of 10 individuals.