European mole cricket

Appearance

The body length is about 40 millimetres in males and 45 millimetres in females. The cricket is dark brown with a silky shimmer and yellowish underside and is covered with fine velvety hairs. The forelegs are powerful and modified for digging. The elytra are half the length of the abdomen and the wings are transparent and netted with veins. They are folded into pleats and seldom used as the cricket normally remains below the ground. The males can be distinguished from the females by the open vein area in the forewing known as the 'harp' while the females lack the external ovipositor that is possessed by other crickets.

Status

In the United Kingdom this species is considered endangered as there have been only four confirmed sightings between 1970 and 2001. It used to occur in 33 vice-counties, mainly across southern England but also in South Wales, western Scotland and Northern Ireland. Its range has contracted and it may now be extinct. There is an action plan that aims to maintain any surviving colonies, establish a captive breeding programme and establish self-sustaining colonies throughout its former range.

Behavior

The female cricket lays 100 to 350 eggs in an underground chamber in the spring. They hatch ten to twenty days later and she guards them for another two to three weeks. The nymphs moult six times and take from one to three years to reach maturity. Adults and nymphs live underground throughout the year in extensive tunnel systems that may reach a depth of over a metre in the winter. They are omnivorous, feeding on roots, tubers and rhizomes and a range of soil invertebrates. They often leave neat circular holes in tuberous plants. The males occasionally produce a soft, 'churring' song from within a specially constructed chamber in the burrow system. This acts to amplify the song which is believed to be used for attracting females. The sounds are typically produced on warm mild evenings in early spring and they are similar to the song of the nightjar, "Caprimulgus europeaeus". Natural enemies include rooks, starlings and other birds, shrews, moles, ants, ground beetles, nematodes and mites. During winters interrupted by thaws, fungal diseases may cause mass deaths.

Habitat

This mole cricket occurs throughout much of the Western Palaearctic, but is replaced by similar species in the south and east, and becomes rare or absent towards the north. Favoured habitats include damp rich soils, flood plains, reservoir edges, irrigated and well-fertilized fields and vegetable gardens. The family Gryllotalpidae includes several similar species.