Cold tolerance in terrestrial invertebrates inhabiting subterranean habitats

• Published in: International journal of speleology 2014-09, Vol.43 (3), p.265-272
• Main Authors: Novak, Tone, Sajna, Nina, Antolinc, Estera, Lipovsek, Saska, Devetak, Dusan, Janzekovic, Franc
• Format: Article
• Language: English
• ISSN: 0392-6672; 1827-806X
• DOI: 10.5038/1827-806X.43.3.3

Most organisms are able to survive shorter or longer exposure to sub-zero temperatures. Hypothetically, trogloxenes characterized as not adapted, and troglophiles as not completely adapted to thermally stable subterranean environment, have retained or partially retained their ability to withstand freezing, while most troglobionts have not. In this paper, the authors tested this hypothesis experimentally on 37 species inhabiting caves in Slovenia, analyzing their lower lethal temperatures in summer and winter, or for one season, if the species was not present in caves during both seasons. Specimens were exposed for 12 hrs to 1°C-stepwise descending temperatures with 48 hr breaks. In general, the resistance to freezing was in agreement with the hypothesis, decreasing from trogloxenes over troglophiles to troglobionts. However, weak resistance was preserved in nearly all troglobionts, which responded in two ways. Data on cold resistance can serve as an efficient additional measure of adaptation to particular hypogean environments.