Winter is definitely in full swing lately, with 4 inches of snow today and temperatures for tonight predicted to hit -10C. You would be forgiven for thinking that no insect life could possibly be active in this weather....however, for anyone who fancies an entomological challenge, there is one species that you may just encounter on these cold, snowy days.
Known as the 'snow flea', Boreus hyemalis, is not a flea at all, but a member of the Family Mecoptera, better known as the scorpion flies. Scorpion flies are more often seen in the UK in the summer months, when three species of the Genus Panorpa are on the wing, the most numerous being Panorpa communis and P. germanica, which can be seen commonly at Langford. The snow flea however is active in the middle of winter, from October to April and is most easily seen on snow covered ground, as the dark coloured insects crawl and jump over the snow.
The imago (adult) insects are about 5mm in length and typically live inside clumps of moss - indeed they can be found by searching through such clumps, but as already mentioned, are most easily seen on snow. Both male and female insects are wingless, the male possesses modified wings used for mating, whereas the female has a long ovipositor at the end of the abdomen used for egg laying. Long biting mouthparts are also characteristic and the insects are predatory, feeding on other invertebrates.
Snow fleas undergo complete metamorphosis - that is, a four stage lifecycle of egg, larva, pupa, imago. The larvae, which are active in spring and summer live underground and are also predatory on other invertebrates.
Interestingly, the snow fleas' distribution in the UK favours the colder north and east of the country.