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How many insects are there?

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How many insects are there?

How Many Species of Insects Are There on Earth?

tl;dr

Scientists estimate that Earth is home to about 5.5 million insect species , but only around 1 million have been formally described and named. That means roughly 80% of insect species remain undiscovered , making insects one of the biggest frontiers in biological research.

So, how many insects are we talking about?

It's one of those deceptively simple questions—how many insect species are there? You'd think we'd have a solid number by now, given how long we've been studying nature. But the reality is far messier, and way more fascinating.

Current estimates put the number at around 5.5 million species , with just 1 million officially described and named123 . That's not just a statistic—it's a glimpse into how little we still know. Insects already make up over half of all known animal species4 , and yet the vast majority are still hiding in plain sight.

And yes, that's despite the fact that insects have been around for more than 350 million years —long before dinosaurs, flowers, or even birds entered the scene5 .

What do we actually know so far?

As of now, scientists have named about 1 million insect species . That alone makes them the most diverse group of animals on Earth123 . If you added up all described eukaryotic species—things with complex cells—over 50% of them would be insects1 .

And it's not just about the number of species. It's also about how many individuals are crawling, flying, or burrowing around. The best estimates suggest there are 10 quintillion (that's 10 followed by 18 zeros) individual insects alive at any moment67 . That works out to about 1.4 billion insects per human being5 . So if you're feeling outnumbered—you are.

Wait, weren't there estimates of 30 million?

Yes, earlier studies did suggest sky-high numbers— up to 30 million species62 . These were often based on how specialized insects can be with their plant hosts. But scientists have since pulled back from that figure. More refined models and new data have led to a current consensus of around 5.5 million insect species1238 .

A 2018 global review estimated:

That said, there's still wiggle room: recent models suggest the true number could lie somewhere between 2.6 and 7.2 million8 .

Where are all these insects hiding?

They're everywhere—but they're not evenly spread out. Five insect orders dominate the scene:

  1. Beetles (Coleoptera) – Around 1.5 million species , famously causing biologist J.B.S. Haldane to joke that God must have "an inordinate fondness for beetles"38 .
  2. Butterflies and moths (Lepidoptera) – About 180,000 species , including 18,000 butterflies8 .
  3. Flies and mosquitoes (Diptera) – Roughly 120,000 species , with mosquitoes alone making up about 3,5008 .
  4. Ants,bees,wasps(Hymenoptera) – At least 22,000 species of ants and 20,000 species of bees98 .
  5. True bugs (Hemiptera) – Including cicadas, aphids, and others1 .

These five orders account for a whopping 90% of all described insect species1 .

So why is it so hard to count them all?

Good question. There are a few reasons:

1. Not enough taxonomists

We're facing what researchers call a "taxonomic impediment." There simply aren't enough experts to name everything. At current rates—about 20,000 new species described per year —it would take centuries to catch up1 .

2. Sampling gaps

Tropical regions, which are likely the richest in insect diversity, are under-sampled compared to temperate areas10 . Many undiscovered species are also smaller, rarer, or more geographically restricted , making them harder to find.

3. Cryptic species

Some insects look identical but turn out to be genetically distinct . These are called cryptic species , and they complicate things even further. Estimates suggest 1–2% of species might be cryptic , hiding in plain sight23 .

Why does this matter?

It's not just academic curiosity— insects matter more than most of us realize.

Pollination

Most flowering plants (including many crops) depend on insects to reproduce. Just wild bees alone contribute pollination services worth up to $689 billion annually11912 .

Ecosystem services

Insects are essential to:

  • Nutrient cycling
  • Soil health
  • Waste breakdown
  • Natural pest control

They're also the foundation of many food webs , feeding birds, reptiles, amphibians, and mammals11 .

Ecosystem health indicators

Insect diversity is increasingly used as a proxy for ecosystem health . Especially in under-studied regions, insects can reveal how well an environment is holding up under pressure13 .

Final thoughts

We've described a million insect species. We think there are at least 5.5 million. That means we're only 20% of the way there . And with each new discovery, we're not just adding names to a list—we're learning more about how life on Earth really works.

Insects aren't just everywhere—they're everything. And until we fully understand them, we're only getting part of the story.

Footnotes

  1. https://en.wikipedia.org/wiki/Insect_biodiversity ↩ ↩2 ↩3 ↩4 ↩5 ↩6 ↩7

  2. https://www.annualreviews.org/doi/10.1146/annurev-ento-020117-043348 ↩ ↩2 ↩3 ↩4 ↩5

  3. https://pubmed.ncbi.nlm.nih.gov/28938083/ ↩ ↩2 ↩3 ↩4 ↩5 ↩6

  4. https://en.wikipedia.org/wiki/Insect ↩

  5. https://www.royensoc.co.uk/understanding-insects/facts-and-figures/ ↩ ↩2

  6. https://www.si.edu/spotlight/buginfo/bugnos ↩ ↩2

  7. https://www.discoverwildlife.com/animal-facts/insects-invertebrates/what-are-insects ↩

  8. https://theconversation.com/how-many-types-of-insects-are-there-in-the-world-247333 ↩ ↩2 ↩3 ↩4 ↩5 ↩6

  9. https://www.ipbes.net/node/11774 ↩ ↩2

  10. https://phys.org/news/2024-08-earth-millions-undescribed-insect-species.html ↩

  11. https://files.ipbes.net/ipbes-web-prod-public-files/un_environment_foresight_brief_no_011_insect_pollination_0_0.pdf ↩ ↩2

  12. https://files.ipbes.net/ipbes-web-prod-public-files/spm_deliverable_3a_pollination_20170222.pdf ↩

  13. https://www.nature.com/articles/s43247-023-00896-1 ↩