Although many arthropods are freeze tolerant (able to withstand internal ice), small-bodied terrestrial arthropods such as mites are thought to be constrained to freeze avoidance. We field-collected active adult red velvet mites, Allothrombium sp. (Trombidiidae), in winter in Southwestern Ontario, Canada, where temperatures drop below -20°C. These mites froze between -3.6° and -9.2°C and survived internal ice formation. All late-winter mites survived being frozen for 24 h at -9°C, and 50% survived 1 wk. The lower lethal temperature (LLT50; low temperature that kills 50% of mites) was ca. -20°C in midwinter. Hemolymph osmolality and glycerol concentration increased in midwinter, accompanied by decreased water content. Thus, this species is freeze tolerant, demonstrating that there is neither phylogenetic nor size constraint to evolving this cold tolerance strategy.

中文翻译：

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越冬的红色天鹅绒螨是耐冻的。

尽管许多节肢动物具有耐冻性（能够抵御内部冰冻），但人们认为诸如螨虫之类的小陆生节肢动物只能避免回冻。我们现场收集了活跃的成人红色天鹅绒螨Allothrombium sp。（Trombidiidae），冬天在加拿大安大略省西南部，温度下降到-20°C以下。这些螨虫在-3.6°至-9.2°C冻结，并在内部结冰中幸存下来。所有的冬末螨都在-9°C下冷冻24小时，其中50％在一星期内存活。较低的致死温度（LLT50；杀死50％螨虫的低温）约为。仲冬时为-20°C。冬季中血淋巴渗透压和甘油浓度增加，同时水分含量降低。因此，该物种具有耐冻性，