Winter survival and cold hardiness in Stercutus niveus (Oligochaeta; Enchytraeidae)

Stercutus niveus Michaelsen, 1888 (Oligochaeta; Enchytraeidae) reaches densities of more than 1000 individuals per m(2) in the litter layer of deciduous forests in Central Europe during winter. As no vertical movement into deeper soil horizons and no cocoon production takes place during this period, the worms have eco-physiological strategies to survive the sub-zero temperatures that frequently occur in the absence of a protecting snow cover. The ability of S. niveus to supercool its body fluid to -15 degrees C prevents the worms from freezing. The supercooling point (SCP) is significantly affected by the presence of gut contents and SCP data show a bimodal distribution throughout the winter. Glycerol, a potential antifreeze agent, was detected in the body fluid of the worms. (C) 1998 Elsevier Science B.V.