INSECTSInsects
  
By and large many people regard insects (and there are plenty in Africa!) with horror as either pests or revolting creepy-crawly creatures to be avoided or worse still, squashed without mercy. Infamous as they may be, insects play such a vital role in the food chain and the global eco-system of the planet that without them life as we know it would cease to exist.
 
Insects are in a great part responsible for the break down of organic material such as plant, animal and human remains, the elimination of animal waste, the aeration of the soil and of course the vastly important task of plant pollination. They are an essential food source to many birds, fish, reptiles and amphibians, while in some parts of the world they also constitute a significant part of the human diet.

The plight of endangered mammals is often given considerable exposure, however, insects and related species, many which are endangered, receive little attention despite their importance in the overall balance of nature.

In excess of a million species of insects have already been identified worldwide and it is estimated that at least an equal number but possibly as many as three to four million, still remain unidentified. Notwithstanding the fact that insects are one of the most abundant life forms on earth, however, with the number of insect species exceeding that of all other species combined, use of insecticides, proliferation of invasive alien vegetation and encroachment into their natural habitats is having its consequence and insect populations are being alarmingly reduced or decimated. Untold numbers of species have been adversely affected by man's selfish violation of rain forests, wetlands, bushveld and savannas. Many species, some possibly not even yet identified are threatened or possibly already extinct while others are moving from their normal distribution ranges in order to survive. Insect control in the past has also been highly irresponsible with indiscriminate use of non-specific insecticides killing not only the pests but also all their natural predators and other valuable and harmless species.
A spider catching wasp (Batozonellus fuliginosus) visits a flower.
Note the pollen adhering to the wing bases.

Judicious control
Their very diversity and ability to breed in vast numbers make judicious control of insect life essential to human’s well-being as many insects are agricultural pests while others are instrumental in the spread of both human and animal diseases, the Mosquito, tsetse fly, Sand fly and others have wreaked havoc in many parts of Africa causing untold suffering and deaths. The natural predators of insects - other insects, reptiles and birds are essential in maintaining the balance of nature and perform an essential role in controlling insect populations. Despite every effort, for example, man alone has never been able to control the common fly responsible for the transmission of many diseases. Without the help of spiders, and the many other creatures that prey upon them, for they are a high source of protein, disease-carrying flies possibly have the potential of decimating humankind. One authority has estimated that if one were to remove all the insects, not including other creatures that catch houseflies within one year the entire planet' surface would be covered one meter deep in the offspring of just one pair of houseflies.
Responsible and enlightened authorities are increasingly becoming aware of the important role insects play in the overall ecological equilibrium as well as their value as indicators for conservation monitoring. That this is so is substantiated by an international effort to inventory the world's natural history collections in compliance with the 1992 United Nations Environment Program Convention on Bio-diversity. Entomologists and Agriculturists are moreover increasingly making use of biological methods to control the numbers of crop destroying insects by introducing natural predators of the unwelcome pest, its eggs, larva or pupa such as Parasitic Wasps and Ladybird Beetles. On the other hand, in many Countries positive steps are being taken to restore natural habitats and encourage the breeding of beneficial insects. In South Africa's Western Cape region two Damsel fly species, the Cape Bluet and the Ceres Stream Damsel fly, both thought to be extinct, were recently reported seen again after the removal of alien vegetation from their habitat.
Insects can readily be distinguished from all other arthropods, that is, animals without backbones, by having a body made up of three distinct parts, they also have six legs and usually two pairs of wings.

The three main parts of the body are the Head, Thorax and Abdomen. The thorax and abdomen are in turn divided into a number of segments. The thorax consists of three segments each one of which carries a pair of jointed legs while the last two segments also each have a pair of wings. In many insects the wings may be adapted in various ways such as with many beetles where the fore wings are adapted into a hard protective shell known as the Elytra which covers the delicate hind wings which are used for flying. In flies the hind wings have been adapted to form two small paddle-like organs, known as Halteres while in other insects the wings may be almost non-existent except for small tubercles on the last two segments. The wings as well as the structure of the veins on the wings are important criteria by which different species are classified.

Here the halteres of the Giant Cranefly (Tipula jocosa) can be clearly seen. Halteres are only found in the order Diptera (flies), they are probably used to control flight which is why flies are able to make such sudden mid-air changes in direction.

This Red-spotted Spittle Bug (Locris arithmetica) which is about to take off, opens its tough fore-wings to free the delicate hind-wings used for flying.

An insect’s abdomen contains the breathing organs, heart, digestive system and sexual organs. There are no legs or wings on the abdomen but it does also have a number of spiracles or breathing holes through which it draws air. The abdomen, being a soft and sensitive part of the body is often protected by a hardened elytra and in many cases may even be difficult to see except from the underside of the body. Some insects, such as certain ant species also have glands in the abdomen through which chemicals can be released for purposes of self defense.
The antennae, eyes and mouthparts are found on the head. Antennae, which function both as smell and as touch organs differ greatly in length and structure and are an important indicator used in identification of insects and families within insect orders. The antennae are also able to pick up the very faint scent of highly complex chemicals known as pheromones which many insects secrete to attract mates, sometimes over great distances.

Compare the coiled proboscis of the Christmas Butterfly (Princeps demodocus) with that of the rostrum of the Assassin Bug
 
Mouth parts are specifically adapted according to the insect’s diet and may be suited for chewing or sucking, some have a short strong piercing rostrum for impaling prey while others have a long delicate proboscis designed to reach and suck up nectar deep within flowers. Carnivorous insects often have well developed and strong mouthparts used for both firmly holding as well as chewing up their prey. Some insects, such as assassin bugs are capable of delivering a nasty bite if handled, their sharp rostrums being easily able to pierce human skin.

The fore-legs of the Mole Cricket (Gryllotalpa africana) is greatly enlarged and perfectly adapted for digging.
The legs of an insect are jointed consisting of a femur (thigh), Tibia (shank) and tarsus (foot). The tarsus in turn also has several joints and usually ends in either a claw or has pads. Many insects have legs that are especially adapted to catching or holding prey while the legs of others are used for digging, running, swimming and other activities necessary for their survival.