Introduction

Abstract

The human animal clearly dominates the world in terms of its impact on the environment and its general effect upon the Earth. Biologically, however, the class Insecta can claim to be the more important. Insects are humanity’s greatest rival for the world’s food resources, both directly by eating the plants cultivated for food, and indirectly as vectors of disease-causing organisms. In terms of evolution, insect pests kept humanity at a subsistence level for thousands of years. But as we evolved, we developed skills in agriculture, chemistry and medicine, and now we have many weapons with which to attack the insect hordes and the parasites they transmit. However, human progress in the battle against the insects is somewhat like climbing a steep sand dune-for every metre climbed, one slips back half a metre; at any point a quick landslide can precipitate one down to the base again, and each step requires a major effort. A constant striving, and a vast financial expenditure on a day-to-day basis, does keep the insect pests at bay—just!