Physical and chemical changes associated with seasonal alterations in freezing tolerance in the adult northern tenebrionid, Upis ceramboides

摘要: Abstract The adult tenebrionid beetle Upis ceramboides overwinters in the northern taiga forests of North America a hibernaculum typically just beneath loose tree bark above snowline. beetles may be exposed to temperatures as low −55°C, which is approximately lower limit cold tolerance found specimens collected mid-winter. Supercooling points average −6.3°C throughout year and, contrary expectation, show no seasonal variation spite major alterations haemolymph composition and freezing tolerance. Summer are incapable withstanding below supercooling point but increases during fall (September–November) lethal temperature (LLT) maintained at ca. −55°C until March, after it gradually rises summer level −6°C. Changes closely associated with polyhydric alcohols sorbitol threitol. Neither polyol present measureable amount summer; accumulates an concentration 0.44 M/l winter threitol reaches 0.25 M/l. contain about 14% more water than other seasons. thus undergoes unique changes physical chemical characteristics that enable tolerate severe, prolonged subfreezing temperatures.