Fig. 2. Percentage survival (mean ± S.E.M.; N=50) of first instar and newly moulted pre-reproductive S. avenae reared at 10°C, 72 h after rapid cold-hardening (RCH) treatment. Aphids were rapidly cold-hardened at 0°C for increasing periods of time, prior to exposure to the discriminating temperature (–11.5°C for first instar nymphs and –12°C for newly moulted adults). Means with the same letter are not significantly different at P<0.05 (Tukey multiple comparison test).