The European mole cricket, Gryllotalpa gryllotalpa is widely distributed in the warmer areas of Europe and introduced in the US. It lives mainly in the ground where it feeds on soil invertebrates (e.g. earthworms and insect larvae) and on plant roots. It is usually of no or little significance as a pest and only a problem if it occurs in large numbers. Gryllotalpa gryllotalpa is classified as endangered or threatened in several European countries where it is now protected by law.
Life cycle and appearance of European mole cricket
The European mole cricket has forelegs that are greatly enlarged with finger-like projections; an adaptation for burrowing in the soil. The adults are 35-50 mm long with a greyish brown to yellowish brown, stout body, covered with a velvet-like coating of fine hairs. It has short forewings and large, elongate hindwings, which are rolled longitudinally and relatively inconspicuous when the insect is at rest.
Mole crickets burrow through the soil forming tunnels a few cm below the surface. At night, especially in warm, summer evenings, adults might come to the surface and may fly in swarms. Adult males are capable of stridulating which they do to attract females.
After mating, females form a large subterranean chamber in which they lay 100-300 eggs. The eggs hatch within 2-3 weeks but the female continues to tend its brood until the nymphs reach the second instar. Then the nymphs leave to feed and develop independently. Developing from egg to adult takes about a year in southern Europe and up to 18 months in cooler regions.
The European mole cricket browses indiscriminately on roots and the basal part of stems. Seedlings may be destroyed and young plants may wilt and die. In strawberry, for example, the crickets also feed on the crowns and developing fruitlets or fruit.