Fig. 2. Reciprocal test to determine whether rapid cold-hardening (RCH) at 16°C reduced mating performance at the original rearing temperature of 23°C. RCH pairs (N=19) were acclimated at 16°C for 2 h immediately prior to a 1-h mating trial. Control pairs (N=20) were held continuously at 23°C prior to the mating trial.