Table 1.

Physiological parameters in the field-collected adults of Pyrrhocoris apterus

ParameterValue in OctoberValue in December
Dry mass (mg)18.1±6.318.6±3.7
Hydration (mg water mg-1 DM)1.78±0.411.45±0.32
Haemolymph osmolality (mosmol kg-1)326±21904±55***
Conc. of ribitol (μg mg-1 DM)trace26.96±8.14
Conc. of sorbitol (μg mg-1 DM)trace3.80±2.88
Supercooling point (°C)-11.0 (-4.8, -15.2)-19.2*** (-16.4, -20.3)
Lt50 at -15°C (days)<118.9±3.4
  • DM, dry mass.

    Each value represents either a mean ± s.d. or, in the case of supercooling points, median (25%, 75% percentile); (see text for N). The differences between October and December means or medians were statistically analyzed using unpaired two-tailed t-tests or two-tailed Mann—Whitney U-tests, respectively (*P<0.05; **P<0.001; ***P<0.0001).