Approximately how many known insects are there?

• A. 100,000
• B. 1,000,000
• C. 10,000,000
• D. 1,000

Answer: (B)

Think about how many insect kinds scientists have actually named and described. The documented count is about one million described insect species. That figure reflects what has been formally identified in the scientific literature. There are likely many more species that remain undescribed, but when we say “known,” we’re talking about described species, which is why one million is the best answer. The other numbers don’t fit the documented counts: far too few to cover the diversity scientists have described, and much higher than the documented number of described insect species.