Insects make up about 80 percent of all known species of animals and might account for even more, since researchers actually don't know exactly how many species of insects there are. It's estimated that there are 6 million to 10 million species of insects, but only about 900,000 have been identified. Despite this, insects are one of the least-studied types of animals.
More facts about insects:
- Insects are crucial to Earth's ecosystem and to the agriculture market. It's estimated that the pollination that insects provide is worth about $217 billion US Dollars (USD) a year.
- Many types of insects are bioluminescent, which means that they produce and emit light naturally. Fireflies are perhaps the most well known, but glow worms, click beetles and some types of centipedes and millipedes also are bioluminescent. Some scorpions are too, but they're not insects — they're arachnids.
- Insects might be undergoing a mass extinction. One study suggests that about 44,000 insect species have become extinct in the past six centuries or so. It's unclear how many insect species have gone extinct or even how many are threatened because they have not been studied thoroughly.