Winter in Scandinavia is not considered an insect collecting season. Snow and ice are good for skiing and skateboarding, not for butterfly hunting. At winter, northern entomologists may enjoy a break, free of collecting work, finally with plenty of time to sort, look at and identify what was collected during the summer.

Yet, in reality, even in the middle of Norwegian winter when all the land finally becomes covered with snow, some insects remain active, quite unexpectedly by non-entomologists. One of the most interesting examples is the genus Boreus of scorpionflies (snow scorpionflies).

(Male of Boreus hyemalis)

(Female of Boreus hyemalis)

Adults can be spotted walking on snow during the warm spells when the temperature rises to zero degree Celsius and above. Adult scorpionflies emerge in October, well before the snow cover is established. They remain active and females keep laying eggs (on mosses) until April. Snow scorpionflies are wingless and when navigating on the snow surface they walk or jump achieving a speed of up to 1.2 m per minute.

Next time you are taking a walk in winter forest, have a closer look at the snow surface: the chances are you are not walking 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 photos: Wikipedia.