ICE FORMATION IN THE FREEZE-TOLERANT ALPINE WETA HEMIDEINA-MAORI HUTTON (ORTHOPTERA, STENOPELMATIDAE)

1) The New Zealand weta Hemideina maori is shown to tolerate freezing to -9-degrees-C for a minimum of 20 hours. 2) Ice nucleation occurred at a core temperature of -0.8-degrees-C to -2.5-degrees-C in animals e xposed to -5-degrees-C and ice formation subsequently progressed at a rate of about 15% of the total bodywater per hour during the first 3-4 hours. 3) The maximum (''equilibrium'') ice content increased from 15 % at -1-degrees-C to ca. 82% at -6-degrees-C, and no increase in ice c ontent was observed upon further cooling. 4) No correlation between ic e content and mortality was observed, implying that lethal cryoinjury in Hemideina maori can be attributed to factors other than cellular de hydration and high solute concentration.