DINKELACKER, SA; COSTANZO, JP; LEE, RE; Miami University; Miami University; Miami University: Cold Hardiness and Desiccation Resistance in Hatchling Emydoidea blandingii

Parameters of cold hardiness and desiccation resistance of hatchling Blanding�s turtles (Emydoidea blandingii) were examined to suggest potential overwintering sites. Terrestrially overwintering hatchlings either tolerate freezing or avoid ice nucleation behaviorally or physiologically by supercooling. The ability of hatchlings to supercool depends upon their resistance to inoculative freezing. In the absence of external ice nuclei, hatchlings supercooled to �14.3 &degC. Furthermore, supercooled hatchlings were able to survive 1 h exposures to �8.0 &degC and 7 d exposures to �4.0 &degC. However, when immersed in frozen soil, their ability to remain supercooled was compromised by their inability to resist inoculation by external ice nuclei below �1.2 &degC. Hatchlings survived somatic freezing to �3.5 &degC for 72 h. This profound freeze tolerance is comparable to that of hatchling painted turtles (Chrysemys picta) and box turtles (Terrapene ornata). Evaporative water loss rates of E. blandingii hatchlings (4.1 mg g^-1 d^-1) were intermediate to both terrestrial and aquatic overwintering turtle species. Our results suggest that hatchling E. blandingii possess physiological adaptations that may allow them to overwinter in terrestrial habitats. However, due to the lack of inoculation resistance it is doubtful that hatchling E. blandingii use their pronounced ability to supercool, but rather they rely on freeze tolerance.