The cold hardiness of overwintering stages affects the distribution of temperate and cold-zone insects. Studies on
Erebia, a species-rich cold-zone butterfly genus, detected unexpected diversity of cold hardiness traits. We expanded our investigation to eight Satyrinae species of seven genera. We assessed
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The cold hardiness of overwintering stages affects the distribution of temperate and cold-zone insects. Studies on
Erebia, a species-rich cold-zone butterfly genus, detected unexpected diversity of cold hardiness traits. We expanded our investigation to eight Satyrinae species of seven genera. We assessed Autumn and Winter supercooling points (SCPs) and concentrations of putatively cryoprotective sugars and polyols via gas chromatography–mass spectrometry.
Aphantopus hyperantus and
Hipparchia semele survived freezing of body fluids;
Coenonympha arcania,
C. gardetta, and
Melanargia galathea died prior to freezing;
Maniola jurtina,
Chazara briseis, and
Minois dryas displayed a mixed response. SCP varied from −22 to −9 °C among species. Total sugar and polyol concentrations (TSPC) varied sixfold (2 to 12 μg × mg
−1) and eightfold including the
Erebia spp. results. SCP and TSPC did not correlate. Alpine
Erebia spp. contained high trehalose, threitol, and erythritol;
C. briseis and
C. gardetta contained high ribitol and trehalose; lowland species contained high saccharose, maltose, fructose, and sorbitol. SCP, TSPC, and glycerol concentrations were affected by phylogeny. Species of mountains or steppes tend to be freeze-avoidant, overwinter as young larvae, and contain high concentrations of trehalose, while those of mesic environments tend to be freeze-tolerant, overwinter as later instars, and rely on compounds such as maltose, saccharose, and fructose.
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