Divergent mechanisms of frost-hardiness in two populations of the gall fly, Eurosta solidaginsis

摘要: Abstract Two populations of the gall fly Eurosta solidaginsis utilize different strategies to endure seasonal exposure temperatures below freezing. Both are freezing tolerant. In north temperate populations, supercooling points rise from −10.2°C −6.2°C following exposures This level is maintained throughout winter and ensures frequent prolonged periods tissue South depress point −14.2°C during autumn early winter, this depression precludes extracellular ice formation supra-optimal temperature fluctuations. During mid-winter, same as in northern groups. accumulate three principal cryoprotective agents first frost (glycerol, sorbitol trehalose). Cryoprotectants levels do not peak until 4–6 weeks after frost. southern accumulation profile characterized by a high initial rate synthesis, protective overshoot pronounced The relative survival advantages each strategy discussed.