What are Beetles?

Michael Anissimov
Michael Anissimov

Beetles, members of the order Coleoptera, are the most diverse group in the animal kingdom, with the largest number of species. Over 350,000 species have been described by science, with estimates putting the total number of species between 5 and 8 million. About 25% of all known life-forms and 40% of described insect species are beetles.

Different types of beetles.
Different types of beetles.

These bugs are placed in phylum Arthropoda (arthropods), class Insecta (insects). Like other insects, they have a hard shell, open circulatory system, and are primarily small invertebrates. What distinguishes them from other insects is their hardened forewings, from which the order gets its name: coleo means shield and ptera means wing.

Beetles are the most diverse group in the animal kingdom.
Beetles are the most diverse group in the animal kingdom.

Once, the biologist JBS Haldane was asked if he could say anything about God from his study of nature. Haldane replied, "He must have an inordinate fondness for beetles." Discovering and classifying new ones is truly a challenge for biologists, and hundreds or thousands of new species are discovered every year, mostly in the tropical zone. When scientists leave out a net and shake trees in the tropics, thousands of the insects fall into the net. They may be the easiest order of animal to find new species within.

The rhinoceros beetle is known for its strength.
The rhinoceros beetle is known for its strength.

Beetles range wildly in size. The smallest known, Nanosella fungi, is 0.0098 inches (0.25 mm) in length with a weight of 0.4 mg. The largest, Titanus giganteus, exceeds 8 inches (20 cm) in size and weighs over 100 grams. They set other interesting records as well. For instance, the rhinoceros beetle species, Dynastes hercules, can lift 850 times its own weight, a record left unchallenged until it was discovered that the tropical mite, Archegozetes longisetosus, could lift 1,150 times its own weight. That's like an elephant that can carry 1,150 other elephants on its back.

Because of their abundance and diversity, beetles are popular subjects for insect collections. They are dried, mounted, and put on display in hundreds of thousands of public and private collections throughout the world. It is through their study that many of the early post-Darwin biologists came to understand evolution better.

The ladybug is a beetle.
The ladybug is a beetle.
Michael Anissimov
Michael Anissimov

Michael is a longtime wiseGEEK contributor who specializes in topics relating to paleontology, physics, biology, astronomy, chemistry, and futurism. In addition to being an avid blogger, Michael is particularly passionate about stem cell research, regenerative medicine, and life extension therapies. He has also worked for the Methuselah Foundation, the Singularity Institute for Artificial Intelligence, and the Lifeboat Foundation.

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Discussion Comments


Ladybugs have taken over my ceilings and windows. Several of my friends who live in the area also say that they have groups of ladybugs covering their ceilings, especially in the corners.

They are not harmful, but I did not sign up for household beetles! They startle me when they fly by my head, because I can hear the fluttering of their wings. They are pretty to look at, but I really have no use for them in my home.


@giddion – It probably was a rhinoceros beetle. They hiss if you poke at them with a stick.

June bug beetles also hiss when you mess with them. These metallic green beetles are so pretty. They are so bright that they really stand out in the grass.

My dad told me that the hissing sound is just air getting pushed out when they flatten their wings against their backs. I think it is intended to scare off predators, though.


My dog gets freaked out when he sees a really big black beetle. They are pretty slow moving as they crawl across the grass, and my dog will bark and paw at them.

I sometimes hear them make a little hissing sound, especially when he paws at them. This is a little scary, and it gets him barking all over again.

I have no idea what type of beetle this was. What kind of beetle hisses when you touch it?


Every night, these annoying brown beetles knock themselves silly in my carport. They fly around the light in such a hysterical manner that they wind up slamming into the wall, the ceiling, and anything else that might come across their paths.

One hit me in the head one night as I was walking to my car. It fell onto its back on the concrete, buzzed around a little, and got right back up. These beetles are pretty tough.


Some beetles can be very destructive and cause havoc in agriculture. They feed on a variety of grains and cause massive damage.

One of these beetles is khapra beetle, a dangerous beetle, native of India, but found in other countries as well.


Not all, but some beetles are scavengers. They play a big role in consuming dead animals. In Canada and United States there are about 24,000 species of beetles.

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