We have been brought up to fear insects. We regard them as unnecessary creatures that do more harm than good. Man continually wages war on them, for they contaminate his food, carry diseases, or devour his crops. They sting or bite without provocation; they fly uninvited into our rooms on summer nights, or beat against our lighted windows.
We live in dread not only of unpleasant insects like spiders or wasps, but of quite harmless one like moths. Reading about them increases our understanding without dispelling our fears. Knowing that the industrious ant lives in a highly organized society does nothing to prevent us from being filled with revulsion when we find hordes of them crawling over a carefully prepared picnic lunch.
No matter how much we like honey, or how much we have read about the uncanny sense of direction which bees possess, we have a horror of being stung. Most of our fears are unreasonable, but they are impossible to erase. At the same time, however, insects are strangely fascinating. We enjoy reading about them, especially when we find that, like the praying mantis, they lead perfectly horrible lives. We enjoy staring at them, entranced as they go about their business, unaware (we hope) of our presence. Who has not stood in awe at the sight of a spider pouncing on a fly, or a column of ants triumphantly bearing home an enormous dead beetle?
Last summer I spent days in the garden watching thousands of ants crawling up the trunk of my prize peach tree. The tree has grown against a warm wall on a sheltered side of the house. I am especially proud of it, not only because it has survived several severe winters, but because it occasionally produces luscious peaches. During the summer, I noticed that the leaves of the tree were beginning to wither. Clusters of tiny insects called aphids were to be found on the underside of the leaves. They were sucking sap from the underside of the leaves of my prize peach tree. I immediately fetched a can of insecticide and sprayed the underside of the leaves thoroughly. I repeated the spraying operation several times before I felt satisfied that I had got rid of all the aphids. For two more weeks, I watched the tree carefully. It seemed that the aphids were gone and the tree was beginning to thrive again. Then, without warning, a large number of ants began to climb the tree. They were making their way up the trunk in long, thin lines. As soon as they reached the underside of the leaves, they set to work on the aphids. They were carrying the aphids’ eggs; they were licking the aphids; they were taking care of the aphids all in return for a little sap which the aphids secrete. I realized that I had been wrong in thinking that the ants were simply thieves. They were in fact the protectors of the aphids. The aphids were supplying the ants with food, and the ants were protecting the aphids from the insecticide spray. It is not always easy to distinguish between things that are beneficial and things that are harmful. It is often necessary to make a distinction between instinct and cleverness.