There are about 60 species of Mole Cricket in the world, with ten in North America. Three of these species are native to North America, and the other seven are accidental introductions, one from Europe, one from Asia and five from South America. All Mole Crickets are omnivorous and they will eat roots below the ground and plant stems above the ground, killing or damaging plants. The three native Mole Crickets are not major pests, but the immigrant species have few natural enemies in America and so their numbers can increase sufficiently to allow them to reach pest status. This is particularly true of the South American species.
European Mole Cricket
The European Mole Cricket(Gryllotalpa gryllotalpa) arrived in America in 1913 and is now well established. It is still common in many parts of Europe where it is considered a pest, but it has become so rare in Britain that it is now a ‘protected species’. Females can fly, but the males have smaller wings which they use to make a ‘song’ to attract the females.
Mole Cricket Song
Male Mole crickets rub their fore-wings together to generate the sound. In the case of the European Mole Cricket this ‘song’ is a low-pitched trill which emerges from an opening in the ground. The male modifies the opening of one of his tunnels to form a small resonating-chamber and a funnel-like amplifier. He sits in the mouth of this tunnel as the sun falls on damp evenings and sings for half an hour or so to advertise his presence. Each ‘song’ can last several minutes and can be heard half a mile away. (listen to a typical mole cricket ‘song’)
Reproduction
Female Mole Crickets have hearing organs on their front legs. They listen to the ‘songs’ of the males, choose the ‘best’ and then fly to his tunnel to mate. 200 or so eggs are laid in a chamber at the end of a tunnel and the female returns regularly to clean them until they hatch as small nymphs. She then continues to protect the young until they are large enough to be independent. They pass at least one winter in the nymph stage and moult several times before they become adults.
Flexible Bodies and Folded Wings
As with the Earwigs and some soil beetles the mole crickets have evolved a relatively long and flexible body to allow easy movement through the soil. This means that the size of the wings needs to be reduced in some way. Some species have lost their wings completely, some have reduced them to a very small size, while others fold them when they are not in use.
Other articles by John Blatchford
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