Entomology, Ornithology & Herpetology: Current Research
Open Access

Abstract

On the Question of Parameters for Evaluating Cold Hardiness of Freeze Tolerant Insects

Natalia Li

The super cooling point (SCP) is the best documented parameter for describing the ability of insects to survive freezing but its value as a predictor of overwintering survival or for estimation of the cold hardiness potential, is limited. According to this study, the SCP is influenced by such factors as polyol and protein concentration in the hemolymph; therefore it can be lower in winter than it is in spring. Nevertheless the quality of ice nucleating process is higher in winter insects due to which insects survive the lowest winter temperatures. The depletion of polyols in spring causes increase of SCP. Unlike in the autumn, when an increase in SCP is associated with development of freeze tolerance, spring changes in SCP of the insects occur simultaneously with loss of cold tolerance. The present study on the freezetolerant Upis ceramboides inhabiting central Yakutia (Eastern Siberia, Russia) shows that SCP itself is not a sufficiently appropriate parameter for evaluation of insect cold hardiness. For these purposes it should be used together with other criteria, such as specific ice nucleating activity and profile of ice nucleating activity