Temporal resolution of cold acclimation and de-acclimation in the Antarctic collembolan, Cryptopygus antarcticus

Abstract.  The Antarctic collembolan, Cryptopygus antarcticus (Willem), can switch its supercooling point (SCP) between 'winter' and 'summer' modes of cold hardiness over a matter of hours. High resolution temporal scaling of the acquisition and loss of cold hardiness is undertaken by assaying changes in the proportion of animals freezing below −15 °C in response to cooling rate, acclimation temperature, and access to food and moisture. Rapid de-acclimation to the 'summer' modal state is readily achieved after 1–6 h in response to warming and access to food; however, rapid acclimation to the 'winter' modal state is only evident in response to slow cooling and narrow ranges of temperature (0–5 °C). The rapid loss of cold tolerance at higher temperatures with access to food, in particular, emphasizes this species' opportunistic responses to resource availability in the short polar summers. Cold hardiness is apparently more readily traded off against nutrient acquisition than vice versa in this maritime Antarctic species.