The World Of Insects

Which group of living beings on this earth are the most successful at survival? If you answered "humans" or "large mammals" you might want to think again.

Insects are the most abundant and diverse group of organisms on earth. They have dominated the planet's life forms for over 400 million years, long before dinosaurs arrived and long after they disappeared. 

Whenever we discuss insects, numbers dominate the conversation. It seems to me that they make up for their small size with sheer variety and volume. For example, for every human being on the planet, there are 200 million insects; for every one pound of human, 300 pounds of insect. About a million species of insects are known, but it is estimated this is a (small) fraction of the total number of insect species in the world. By the way, the million known insect species represent 80 percent of the known species variety of our world. Another mind-boggling statistic: on a given day there are 10 quintillion individual insects alive on our planet. That is 10 followed by 15 zeros.

There are a number of reasons why insects are so formidably successful in survival. Unlike larger animals, the skeleton of insects is outside their body. This exoskeleton makes them strong and robust. Their small size gives them mobility.  Smaller sizes also mean less food needed to survive, and the exoskeleton and a flexible body give insects great weight-bearing capacity. Many insects can fly to avoid predators and find food. Their flight consumes relatively less energy per pound than the flight of birds or airplanes. Insects can adapt to and thrive in many diverse and hostile environments.

Take ants, for example. Whenever I have watched them, I have been struck by their single-minded focus and disciplined march where they sometimes carry loads bigger than their body size. There are an estimated 22,000 species of ants in the world. They can live in virtually any environment except Antarctica and some islands such as Iceland. Edward O. Wilson, the world's foremost ant specialist, discovered that ants behave in a highly complex social manner – next only to humans.

This focus can be seen in other insects. Once I watched a caterpillar eating leaves of a cinnamon tree. It went after the young, tender leaves at the end of a branch, devouring each one systematically, like a lawnmower going back and forth. Within a few minutes it had eaten several leaves!  

We tend to view insects as pests. There are good reasons for this. Mosquitoes, for example, kill more people than all other animals combined: an estimated 600,000 people die every year from malaria.  On the other hand, without insects we would be in trouble. For example, bees pollinate plants and without them we would not have hundreds of types of foods including most fruits and vegetables. Some insects remove waste and others fertilize soil. In the garden many insects help by eating those insects which damage plants. This is one of the foundations of organic agriculture.

Bugs might not be our favourite living things, but as Wilson points out, if we wiped out all insects from this planet, the rest of life on earth - including humanity - would not survive more than a few months.

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