Snow flea

Scientific name: Boreus hyemalis

This flightless relative of the scorpionfly roams across clumps of moss in winter.

Species information

Statistics

Length: around 4 mm

Conservation status

Widespread but local

When to see

October - April

About

Despite their name, snow fleas aren't fleas - though they are thought to be related to them. They belong to the order Mecoptera, which is sometimes known as the scorpionflies. Unlike the more common scorpionflies seen in spring and summer, adult snow fleas are active in the winter months. Another difference is that snow fleas can't fly as they don't have functioning wings. Instead, the wings of male snow fleas have turned into curved hooks that help them cling to females.

They're usually found on clumps of moss in woodlands or on heathland. They can also sometimes be seen crawling or jumping over snow (earning the name snow flea). They jump to escape predators and will often make several jumps in a row, changing direction each time.

How to identify

A dark, yellowish-brown insect with dull yellow legs. It has a long beak-like face. It looks very similar to the scorpionflies seen in summer, but has no wings. In female snow fleas, the wings are so short they're barely present. In male snow flies, the wings have been modified into curved hooks. Females have a long, upcurved ovipositor at the end of their body.