Door 9 of this advent calendar was focusing on snow scorpionflies (genus Boreus), little noticed but very interesting group of insect whose adults are active in winter and can be easily spotted walking on snow when the temperature is staying close to zero degree Celsius. Yet Boreus is not the only insect commonly seen active in winter.

Chionea, another genus of wingless insects active in winter, belongs to the Dipteran family Limoniidae, or limoniid crane flies. These insects can be observed moving on the snow surface at the speed of 0.8 m per minute at temperatures as low as minus six degrees Celsius.

(Snow fly running)

Additional groups of insects active in winter above snow are winter gnats or winter crane flies (family Trichoceridae) as well as representatives of several other fly families.

Next time you are taking a walk in winter forest, have another close look at the snow surface: you and snow scorpionflies are certainly not walking there alone.

References

Hågvar, S. (2011) A review of Fennoscandian arthropods living on and in snow. European Journal of Entomology, 107, pp. 281–298.

Source of the images: Wikipedia