Wart biter bush cricket

Keith Steggall, National Trust Wiltshire Landscape Ranger Keith Steggall National Trust Wiltshire Landscape Ranger
Insect life on Cherhill Down

The wart-biter is the rarest species on the downs, found in only five UK sites.

The Wart-biter Bush Cricket gets its name from an old Swedish practice of allowing the cricket to bite warts from the skin.

It is the rarest species found on the downs, being the only place in Wiltshire where it is found and only one of five sites in the country.  It has declined due to inappropriate grazing and loss of grassland habitat and is now protected under the Wildlife and Countryside Act (1981).

The chalk grassland of Calstone Down provides good habitat for wart-biter as it needs a varied grass structure with bare ground for egg-laying, some shorter turf rich in flora and some tussocky grass which provides shelter from predators such as kestrels.  The eggs hatch out two springs after being laid, the nymphs will go through a number of stages or ‘instars’ before reaching adulthood around late July.

They are difficult to find as the males will only call or stridulate on calm, hot sunny days and then drop down into the grass when sensing danger.  They grow to 31-37mm with the females being recognisable by an egg-laying ovipositor.

Careful management with cattle grazing to create the right conditions has helped this species to thrive here.

Blue butterfly on purple flower

Rare butterflies

The chalk downland of Calstone and Cherhill Downs is the perfect environment for some of the rarest butterflies in the country.