How often have you been disturbed whilst relaxing in the sun, reading a book, or just having a doze, by the strange, high-pitched noise of some little creature in the tree or bush?

This may be just one insect calling, or it may come from a host of them breaking the silence of the afternoon during the summer months.

A Cicada is an insect similar to a grasshopper, although they are not actually related to these, or locusts. They are related to leafhoppers and spittlebugs. They have 2 large wide-apart eyes on the head and 3 small eyes located on top of the head. They usually have short antennae protruding between, or in front of the eyes and transparent, well-veined wings. There are about 2,500 species of Cicada around the world living in temperate to tropical climates, where they are among the most widely recognized of all insects, mainly due to their large size and remarkable acoustic talents.

Cicadas are not harmful to humans and do not bite or sting, but can be pests to several cultivated crops. Many people around the world regularly eat Cicadas but the female is prized most as it is meatier. Cicadas are still eaten in, China, Malaysia, Burma, Latin America, and the Congo and the hells of Cicadas are used in the traditional medicines of China.

Male Cicadas have loud noisemakers called “timbals” on the sides of the abdominal base. Their “singing” is not produced in the same way as with cricket. The timbals are regions of the exoskeleton that are modified to form a complex membrane with thin, membranous portions and thickened “ribs”. Contracting the internal timbal muscles produces a clicking sound as the timbals buckle inwards. As these muscles relax, the timbals return to their original position producing another click. The interior of the male abdomen is substantially hollow to amplify the resonance of the sound. A Cicada rapidly vibrates these membranes, and enlarged chambers derived from the trachea, make its body serve as a resonance chamber, greatly amplifying the sound. They modulate their noise by wiggling their abdomens toward and away from the tree that they are on. Although only males produce the Cicadas’ distinctive sound, both sexes have tympana. It can be difficult to determine which direction Cicada song is coming from, because the low pitch carries well and because it may, in fact, be coming from many directions at once, as Cicadas in various trees all make noise at once.

In addition to the mating song, many species also have a distinct distress call, usually a somewhat broken and erratic sound emitted when an individual is seized. A number of species also have a courtship song, which is often a quieter call and is produced after a female has been drawn by the calling song. After mating, the female cuts slits into the bark of a twig, and into these she deposits her eggs. She may do so repeatedly, until she has laid several hundred eggs. When the eggs hatch, the newborn nymphs drop to the ground, where they burrow. Most Cicadas go through a life cycle that lasts from two to five years. Cicadas live underground as nymphs for most of their lives, at depths ranging from about 30 cm up to 2.5 m. The nymphs feed on root juice and have strong front legs for digging. In the final nymphal stage, they construct an exit tunnel to the surface and emerge. They then shed their skins on a nearby plant for the last time and emerge as adults. The abandoned skins remain, still clinging to the bark of trees. Cicadas are commonly eaten by birds, but a fungal disease is the biggest enemy of this strange insect. Cicadas inhabit both native and exotic plants including tall trees.