Mole Cricket

Introduction

The loud and persistent advertisement call of male mole crickets is a familiar sound in urban Australian gardens and parklands.

Identification

Mole crickets are brown and have characteristic shovel-like fore legs, especially adapted to digging burrows. The abdomen is very soft, and the forewings small and oval-shaped, usually less than half the length of the abdomen.

Habitat

Mole crickets live in urban areas and grassy woodlands.

Distribution

Mole crickets are found throughout Australia, but are most prevalent in well-watered vegetated areas.

Seasonality

Mole crickets are most active during the summer months.

Feeding and diet

These crickets are omnivorous, although some species are known to be pests of turf because they eat the roots of grasses.

Communication

Male mole crickets use their burrows to amplify their calls by positioning themselves at the entrance and facing inwards. It seems that females are able to determine, from the sound produced, whether the males are calling from a damp or dry site. Females are more attracted to males calling from damp sites, where they prefer to deposit their eggs.

Crickets always call at dusk or during the night, whereas grasshoppers call during the day. Mole crickets mostly call when it is wet or when rain threatens, and calling can be induced by watering the lawn in the afternoon. Both male and female mole crickets call. One species, Gryllotalpa monanka, can produce about 200 pulses of sound per second, resulting in a continuous song.

Life history cycle

Unlike many crickets, the female mole crickets show some degree of maternal care and remain in the burrow guarding the eggs and protecting the nymphs.

Breeding behaviours

Only the flightless males produce the loud advertisement call. They call from within a specially constructed burrow which acts as a resonator, making their call louder. This burrow is also designed to allow any interested females access, whilst providing escape routes should a predator be attracted to the call. Females do not call to advertise their position to males, instead using a quieter call to protect their own burrows. The females have fully developed hindwings and are capable fliers.

Economic impacts

Some species are known to be pests of turf, especially in golf courses. One exotic species the Changa mole cricket Scapteriscus didactylus has been accidentally introduced to areas around Newcastle, NSW, but the impacts of this introduction are not yet clear.

Predators

Females of the blue "ant" Diamma bicolor (Order Hymenoptera: Family Tiphiidae) use mole crickets as hosts for their larvae. The large and brighly coloured wingless wasp lays an egg on the paralysed cricket, with the cricket then being used as food for the developing wasp larva.