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.
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.
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
A spider catching wasp (Batozonellus fuliginosus) visits a flower.
Note the pollen adhering to the wing bases.
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.
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
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.
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.
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
Compare the coiled proboscis of the Christmas Butterfly (Princeps demodocus) with that of the rostrum of the Assassin Bug
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.
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.