Grasshoppers, crickets and locusts are insects with long, powerful back legs. Many species can make loud, chirping “songs”. Most grasshoppers and crickets are plant-eating insects that live above ground. Their jaws are designed for biting and chewing. Their young are miniature adults, known as nymphs. Some of these insects are coloured for camouflage, or have bright markings to warn predators that they have a foul taste.

Leaping to safety

Grasshoppers, crickets and locusts have very good senses. As soon as they spot danger, they spring to safety. They have very powerful back legs which they use to make huge jumps. Their muscular legs can also deliver a powerful kick if seized by a predator.

Singing

Most male crickets and grasshoppers make loud chirps to attract females. This is called stridulation. The chirping mating songs are not made with their mouths but with their limbs. Grasshoppers make sounds by rubbing together a leg and a wing. Male crickets make their loud calls by rubbing their wings (not their legs) together. The bottom of each wing is covered with "teeth" like a comb; the friction produces the sound. Females hear the songs through their ears—actually slits in their abdomens or their front legs.

The male mole cricket builds its own amplifier. The shape of its burrow is specially designed to magnify his song, so that, on a still night, it can be heard two kilometres (1.2 miles) away.

Bush cricket

Bush crickets are also known as long-horned grasshoppers or katydids. Some bush crickets are predatory, feeding on other insects or even small lizards. The leaf mimic bush cricket lives in trees. When still, it looks like a dead leaf, but when disturbed, it launches itself into the air. As it leaps, it unfolds its wings and reveals coloured eyespots to startle its attacker.

Ant-loving cricket

The ant-loving cricket is a tiny, wingless, non-singing species. Measuring between three and five millimetres long (0.1–0.2 inch), its spends its entire life in an ants' nest. It feeds on an oily substance given off by ants by licking it from their legs. Up to 50 crickets may be found in one ants' nest at a time, where they are tolerated by the ants—probably because they are useful disposers of their waste.

When it rains in the grasslands, plants start to grow very quickly. The locusts reproduce rapidly to take advantage of the new source of food and become large colonies. New young locusts born after the rains, small wingless versions of the adults called hoppers, are brightly coloured. The hoppers roam along the ground, eating the new young shoots. They band together in groups hundreds of thousands strong.

The hoppers shed their skins (moult) every so often so that they can grow. After moulting about five times, they develop wings and become adults. They have shorter bodies and they change colour, first to brownish-red, then to yellow.

Once adults, the locusts swarm in their millions—sometimes billions. This swarming behaviour is triggered when the adults produce a hormone, called a pheromone. This acts as a kind of chemical signal, causing them all to be attracted to one another.

The locusts roost in trees during the heat of the day, flying off in search of new food in the mornings and evenings. Strong flyers, they can travel 100 kilometres (60 miles) in just one day.

Adult locusts can eat their own weight in food every day. When swarms of hundreds of millions of them descend on an area they will strip it completely bare of all green vegetation in a matter of minutes. No predator can stop them—there are simply too many of them.

Mole cricket

The mole cricket digs tunnels underground where it feeds on plant roots or insect larvae. It has shovel-like forelimbs, perfectly suited for burrowing. Its strong back legs are designed for pushing against the soil rather than for leaping into the air. It can shape its tunnels in such a way that its calls to other crickets are amplified. Mole crickets have wings and may leave their burrows to fly above ground at night.