Biology Publications
Document Type
Article
Publication Date
Spring 2019
Journal
Physiological and Biochemical Zoology
Volume
92
Issue
2
First Page
201
Last Page
205
URL with Digital Object Identifier
https://doi.org/10.1086/702655
Abstract
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.
