Fig. 3. Effect of rapid cold-hardening on the freeze tolerance of cold-acclimated larvae of the Antarctic midge Belgica antarctica. ^* denotes a significant (P<0.05) difference in survival between groups directly exposed to -15 or -20°C and those that were first held at -5°C for 1 h prior to the lower temperature exposure. Values are means ± s.e.m. based on six replicates of 10 individuals.