Snow Flea

Hypogastrura nivicola — the snow flea — is one of several springtail species (class Collembola) that are active on snow surfaces during the late winter and early spring of temperate North America. Snow fleas are NOT fleas (true fleas are insect order Siphonaptera) — they are wingless hexapods belonging to the entirely separate class Collembola, the same group that includes the soil springtails. Snow fleas appear as tiny dark specks on the snow surface, often in dense aggregations at the base of tree trunks where snow meets bark; they jump using the standard springtail furcula spring-loaded organ when disturbed. The most extraordinary biological feature of the species is the production of glycine-rich antifreeze protein (sfAFP) that depresses ice-crystal formation in body fluids and allows the snow flea to remain metabolically active and ambulatory at temperatures down to -20°C — far below the freezing point of normal animal body fluid. The protein structure was solved by Davies' lab at Queen's University in 2007 (Lin et al., PNAS), and the recombinant version is now under intensive pharmaceutical development as a potential cryopreservation reagent for transplant organ storage, blood products, and stem cells. Snow fleas feed on bacteria, fungi, algae, and decaying organic matter under the snow; spring snowmelt revealed populations were the basis of the species' nineteenth-century taxonomic name (nivicola = 'snow dweller').