The role of insects in the eco-system

Untold numbers of insect species have been adversely affected by mans selfish violation of rain forests, wetlands, bushveld and savannas.

 

What insects mean to us and why we need to save our insect populations

By and large many people regard insects 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 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, sandfly 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 Programmes 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 damselfly species, the Cape Bluet and the Ceres Stream damselfly, both thought to be extinct, were recently reported seen again after the removal of alien vegetation from their habitat.

 

Photographs and text copyright: Lambert Smith

 

© COPYRIGHT Lambert Smith, 2010