Rapid cold hardening in Antarctic microarthropods

摘要: 1 Rapid cold hardening was examined in three common Antarctic microarthropods using differential scanning calorimetry over timescales between 3 and 30 h, under field controlled laboratory conditions. 2 In fresh samples cultures of the springtail, Cryptopygus antarcticus (Willem), mites, Alaskozetes (Michael) Halozetes belgicae (Michael), maintained summer field-simulating conditions, supercooling point (SCP) distributions tracked microhabitat temperature variation observation period. 3 Controlled acclimation summer-acclimatized C. caused significant after 12 h at temperatures around 0 °C (+3 to −2 °C). No response obtained higher or lower temperatures, field-fresh winter-acclimatized animals. The latter did not lose hardiness when held positive for h. 4 Gradual cooling 20 from +5 −5 a considerable increase tolerance. Rewarming partially but non-significantly reversed this effect. greatest occurred +3 +1 °C. Maximum faecal pellet production also interval, gut clearance alone sufficient explain observed hardening. 5 It is hypothesized that these species possess hitherto unrecognized capacity alter environmental cues shorter timescale than previously thought, by mechanism relies on neither nor concentration body fluids via water loss. This ability may reduce developmental costs premature entry into an inactive, cold-hardy state.