Temperature dependence-independence of antifreeze turnover in Eurosta solidaginis (Fitch)

Temperature effects on antifreeze metabolism were investigated in two populations (northern and southern) of the golden rod gallfly, Eurosta solidaginis. Sorbitol production was temperature dependent and was triggered by short-term exposure to < +10°C. The maximal rate sorbitol synthesis occurred at 0°C. For both populations, sorbitol was rapidly catabolized during warm acclimation at +20°C. During the first 12 h of warm acclimation, sorbitol levels decreased by 36% (19.7 ± 0.6) to 12.6 ± 1.2 μg/mg) and by 83% (to 3.3 ± 1.7 μg/mg) after 48 h in the northern population. The southern population decreased sorbitol levels 64% (11.8 ± 0.69 to 4.2 ± 0.62) after 48 h. The southern population resynthesized more sorbitol than did the northern population upon re-exposure to 0°C. Glycerol levels increased linearly during the experimental period independent of temperature.