Wart-biter bush-cricket

The Wart-biter bush-cricket (Decticus verrucivorus) gets its unusual name from the Swedish practice of the 1700’s of allowing the cricket to bite warts from the skin! The scientific name verrucivorus derives from the Latin, ‘verruca’ meaning ‘wart’ and ‘vorous’ ‘to devour’. It is able to do this as it has very strong mouthparts.

Fast Facts

Latin name: Decticus verrucivorus

Notable feature: Large bush-cricket with large powerful hind legs

Rarity in the UK: Rare / Common

Where in the UK: Five sites in Southern England - Sussex, Kent and Wiltshire

The Wart-biter is a large bush-cricket, adult’s measure between 31 and 37mm and the ovipositor (egg-laying organ) of the females can measure up to 21mm. It has large, dark eyes and is typically dark green, often with dark brown or black blotches on the body and wings. Its large and powerful hind legs give this species a frog-like appearance.

Like all bush-crickets, the Wart-biter bush-cricket ‘sings’ or stridulates by rubbing its wings together (grasshoppers sing by rubbing their long legs against their wings). Its fairly loud and distinctive song consists of a series of rapidly repeated clicks in short bursts and often lasts for several minutes.

Even though they have wings, Wart-biter’s normally move about by walking. They rarely fly as they are too heavy and their wings are not large enough; most can only fly very short distances, at best 3-4 meters.

For those readers hoping for a novel cure for their pesky warts, you may be disappointed to learn that this treatment is not particularly effective! Unsurprisingly, warts are not a big part of this cricket’s diet. The Wart-biter is omnivorous, feeding on a range of herbs and insects, including other grasshoppers.

Wart-biter bush-crickets are elusive creatures and males only sing during hot, sunny and still weather.

Wart-biter lifecycle

Adults lay single eggs in bare soil close to clumps of grass and these remain dormant for at least two years before eventually hatching in mid-Spring. Several nymphal (immature) stages are passed before the adult stage is reached at the beginning of July. Most adults only survive until September. To provide the right conditions throughout its lifecycle, the Wart-biter bush-cricket requires a mosaic of vegetation structures including bare ground and short turf for egg-laying and early nymphal stages, while taller tussocks of grasses and flowering plants are required for the larger nymphs and adults. Sunny, well-sheltered calcareous grasslands can provide this mosaic and this is typically where Wart-biter bush-crickets can be found.

On the edge

Historically the Wart-biter used to be widespread in southern England, but now it is considered one of Britain’s most endangered insects, protected under the Wildlife and Countryside Act 1981 and the NERC Act 2006. It is also listed as Vulnerable in the Red Data Book.

Environmental changes due to unsuitable grazing systems and other destruction of grassland habitats have caused a significant decline of this species. It is now very rare and only five isolated populations in southern England remain, two of which resulted from reintroductions.

Looking forward

Buglife are conducting surveys for Wart-biter at the five known sites, we fear Wart-biter may have been lost from one of the sites in Sussex and is hanging on by the skin of its teeth at another site.  The Wart-biter working group lead by Natural England plans to secure better management for these sites and investigate the feasibility of another reintroduction.

Find out more about the crickets and grasshoppers of Britain and get involved with recording these fascinating creatures with the Orthoptera Recording Scheme.