Grasshoppers, locusts and crickets - Orthoptera

House cricket, Acheta domesticus

Above is a juvenile house cricket, Acheta domesticus, in the family Gryllidae. It is found in buildings, rubbish dumps and sold as live pet food for lizards, etc. It is not native to the UK, and arrived from North Africa and the Middle East in the 17th century.

Note the antennae, I could not include the entire length in the photograph, but they are filiform and longer than the entire body. This is a rather young juvenile, so there is no sign of wings yet. These will appear larger with each moult until they are fully formed in the final moult. The wings are functional in both sexes. A fully grown specimen is 14 - 20 mm long. Note the two cerci sticking out of the rear, these are very sensitive to air movements.

It is an omnivorous scavenger, and although it does not eat wool, cotton, leather and wood it can damage them by its constant nibbling action. It is not active in the cold, so in the UK it is found indoors in colder months, or in compost heaps and rubbish dumps where the fermenting and decaying provides warmth.

The male makes the shrill chirping noise by rubbing the serrated edges of his forewings together. Only the males produce the sound, and the females hear the sound with hearing organs on their legs.

Both adults and nymphs will die if starved for 1 week.

The female can lay several hundred eggs, usually in batches, in cracks, crevices or soft soil. The eggs are whitish-yellow, about 2.5 mm long and 0.5 mm wide. They hatch in around 2 - 3 months, but this varies greatly with temperature. The nymphs take around 6 months to mature, but again this varies greatly with temperature.

Tettigoniidae

The Tettidoniidae are commonly known as the Bush crickets or Long-horned grasshoppers just to confuse things. They make a sound by rubbing their wings together.

The Great green bush cricket, Tettigonia viridissima

Above is the Great green bush cricket, Tettigonia viridissima. It is in the Tettigoniidae family which contains all the bush crickets and katydids. They are found in southern England, and along the south coast of Wales. This one was photographed in the Dordogne in France.

Adults tend to make short, hopping flights when disturbed, and sometimes don't even bother to fly, they just walk away.

Stridulation is by rubbing the wings together. Their food is other insects. Eggs are laid in the soil where they overwinter and hatch the following spring.

Oak bush cricket, Meconema thalassinum

Above is the oak bush cricket, Meconema thalassinum. This is a female, note the curved ovipositor she will use to lay her eggs under the bark of deciduous trees. A fully grown one will be 13 - 17 mm long, with an ovipositor 8 - 9 mm long. Nymphs are seen from May - August, and adults from August - October.

Both sexes have functional wings at maturity. Though she is called the oak bush cricket, these crickets can be found in a variety of habitats, and are commonly found in lighted rooms at night, though they are weak fliers. In England they are found in or near woodlands, where they are active after dark from around August to November.

The antennae are much longer than the body and are filiform and whip-like. This species is unusual in that unlike most other species the males can stridulate (make a noise by rubbing body parts together) only very weakly by rubbing the forewings. However males do generate sound by "drumming" with one hind leg on a leaf to attract females. They feed on small insects and are active predators.

Mole cricket, Gryllotalpa gryllotalpa

Above is the mole cricket, Gryllotalpa gryllotalpa, in the family Gryllotalpidae. There are 100 species in the world, but only one species in northern Europe, and it is 35 - 46 mm long, and is light chestnut coloured with velvety hairs. In the UK it is a protected species and is found in just a few locations in southern England.

Mole crickets are usually found in damp ground near ponds, streams or lakes. Adults burrow in the ground making extensive tunnels just below the surface. Note the front legs are strongly toothed and modified for digging, and they use their rear legs to push back the soil.

The eggs are laid in a chamber just below the surface too, so they can benefit from the heat of the sun. Unlike most other crickets the female has no external ovipositor. She lays 200 - 300 eggs, and guards and tends the young.

The young hatch in 2 - 3 weeks and leave the nest to fend for themselves about a month later.

Adults and young eat plant roots and insect grubs. Mole crickets in great numbers are considered a pest, but as they eat many pest grubs themselves, they may do more good than harm. The nymphs go through about 10 moults which takes 1 - 2 years to complete. Males stridulate like other crickets by rubbing their forewings together. The southern European mole cricket male, Gryllotalpa vinea, digs special burrows with two funnel-shaped openings to amplify his singing, which can be heard 500m away. In adults the hind wings are fully developed, but their flight is clumsy.

Schizodactylus monstrosus

Schizodactylus monstrosus, above, is found in sandy places - especially by rivers - in Asia. The flattened tarsi (foot segments) are thought to be an adaptation to help it get around and dig burrows in its sandy habitat. It is cannibalistic in captivity. In north east India it is eaten by humans.