No one knows for sure how many different kinds of insects there are.
But based on discoveries of new species in rain forests, scientists think there may be as many as 9 million insect species worldwide. Insects are found almost everywhere on the planet, except in the ocean’s salty waters. They are successful because they adapt to almost any environment. Some also have a unique feature that no other invertebrates (animals without a backbone) have: wings! With wings, insects can travel greater distances to search for food and find a suitable habitat in which to live.
They’re small, but they have a big effect on us. We get silk and honey directly from insects, but the indirect benefits they bring us are an even bigger deal. Because they land inside flowers, bees transfer pollen from one plant to another. Most flowering plants would not survive without this help from insects—and that includes fruits and vegetables. On the topic of food, insects are consumed as a tasty treat in some cultures. There’s a lot of protein in a big, juicy palm grub!
The interactions between humans and insects are not always positive. Although bees and wasps enable crops to grow, caterpillars and beetles can devour those crops. In many tropical parts of the world, a mosquito bite can be more than just annoying. Malaria, carried by a species of mosquito, kills about a half a million people per year. Hundreds of years ago, a disease called the plague killed millions of people. A tiny flea carried the organisms that caused all those deaths.