Environmental physiology of three species of Collembola at Cape Hallett, North Victoria Land, Antarctica

• Published in: Journal of insect physiology 2006, Vol.52 (1), p.29-50
• Main Authors: Sinclair, Brent J., Terblanche, John S., Scott, Matthew B., Blatch, Gregory L., Jaco Klok, C., Chown, Steven L.
• Format: Article
• Language: English
• Subjects: Animals; Antarctic Regions; Antifreeze Proteins - metabolism; cold stress; Cold Temperature; Cold tolerance; Collembola; Critical thermal limits; Cryptopygus; Cryptopygus cisantarcticus; dehydration (animal physiology); Desiccation; desiccation resistance; freeze avoidance; Friesea; Friesia grisea; hemolymph; Hemolymph - metabolism; hemolymph osmolality; Insect Proteins - chemistry; Insecta - chemistry; Insecta - physiology; Isotoma; Isotoma klovstadi; Isotomidae; lethal temperature; Microclimate; mortality; Neanuridae; Osmolality; Osmolar Concentration; Osmoregulation; osmotic pressure; protein synthesis; Stress protein; Supercooling point; Temperature; thermal hysteresis; Water-Electrolyte Balance
• ISSN: 0022-1910; 1879-1611
• DOI: 10.1016/j.jinsphys.2005.09.002

The environmental physiology of three speciesof Collembola: Cryptopygus cisantarcticus, Isotoma klovstadi (Isotomidae) and Friesea grisea (Neanuridae) was investigated from November 2002 to February 2003 at Cape Hallett, North Victoria Land, Antarctica. All three species were freeze avoiding, and while supercooling points were variable on seasonal and daily scales in I. klovstadi and C. cisantarcticus, they remained largely static in F. grisea. LT50 (temperature where 50% of animals are killed by cold) was −13.6, −19.1 and −19.8 °C for C. cisantarcticus, I. klovstadi and F. grisea, respectively. Upper lethal temperature was 34, 34 and 38 °C for C. cisantarcticus, I. klovstadi and F. grisea. Critical thermal minimum onset (the temperature where individuals entered chill coma) was ca. −7, −12 and −8 °C for C. cisantarcticus, I. klovstadi and F. grisea, and 25% of I. klovstadi individuals froze without entering chill coma. Critical thermal maximum (the onset of spasms at high temperature) was 30, 33 and 34 °C for C. cisantarcticus, I. klovstadi and F. grisea. Haemolymph osmolality was approximately 720 mOsm for C. cisantarcticus and 680 mOsm for I. klovstadi, and both species showed a moderate degree of thermal hysteresis, which persisted through the season. Desiccation resistance was measured as survival above silica gel, and the species survived in the rank order of C. cisantarcticus