What Do Beetles Do: Exploring Their Fascinating World

folder_openColeoptera, Insecta
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Convergent Lady Beetle

Beetles are fascinating creatures that play vital roles in our ecosystems. They belong to the order Coleoptera, and with nearly 30,000 species known in the U.S. and Canada alone, they are the largest group of animals on Earth.

These versatile insects serve multiple functions, from pollinators to decomposers, thereby maintaining the balance in nature.

As a beetle enthusiast, you might be interested in their unique physical characteristics. Their hardened outer wings, also called elytra, serve as a protective shield for their fragile flying wings.

Variable Jewel Beetle: You can see its hardened elytra covering the “real” wings

This feature sets beetles apart from other winged insects. Additionally, they have diverse feeding habits; some chew leaves, while others munch on wood or tunnel through stems.

In your garden, you might encounter a variety of beetles, such as leaf beetles, woodboring beetles, and weevils. Many of these insects are helpful, like ladybird beetles, which are known to be efficient aphid predators.

However, some beetles can also have negative impacts, causing damage to plants or invading your pantry.

The Wondrous World of Beetles

Understanding Coleoptera

When you dive into the vibrant universe of beetles, you’ll find yourself surrounded by over 400,000 known species. Beetles are part of the order Coleoptera, which makes up the largest group of insects on Earth.

These fascinating creatures have a diverse range of sizes, shapes, and colors, making them one of the most interesting orders to study.

Beetles generally have two pairs of wings, with the first pair hardened and thickened, serving as a protective cover for the more delicate, second pair of wings.

This unique characteristic helps you distinguish beetles from other winged insects, such as cockroaches and ticks.

Species Diversity

Beetles exhibit an astonishing degree of diversity among species, accounting for approximately a quarter of all animal species.

They are found in environments all over the world, from tropical forests to arid deserts, adapting their structures and functions to their surroundings.

Some beetles are key players in their ecosystems, pollinating nearly 90% of the world’s flowering plant species.

Others are excellent decomposers and become the cleaning crew of nature.

Thick Legged Flower Beetle: Beetles can be excellent pollinators

The life cycle of beetles is also quite fascinating. They undergo complete metamorphosis, evolving from eggs to larvae, then pupae, and finally reaching their adult form.

This process takes around 7 to 10 days for some beetles, though the duration varies among species.

With their incredible species diversity and essential roles in various ecosystems, beetles truly form a wondrous world worth exploring.

So, the next time you come across a beetle in your garden or on a hike, take a moment to appreciate its extraordinary existence.

Physical Characteristics of Beetles

Color and Shape

Many beetles come in a variety of colors, ranging from black, brown, and other vibrant hues.

Their body shapes vary greatly but most have an oval or slightly elongated form. For instance, you might easily recognize the bold patterns of ladybird beetles.

Size and Legs

Beetles can vary greatly in size, with some minuscule species and others growing quite large, like the impressive Titanus giganteus.

Regardless of size, all beetles have three pairs of jointed legs. These legs, attached to their thorax, enable them to move efficiently to gather food, escape predators, and perform other vital tasks.

Wings and Flight

Beetles possess two pairs of wings. The front pair, known as elytra, is a protective hardened shell and the second pair is actually used for flight.

Most beetles have the ability to fly, although a few are flightless due to their wing structure or living environment.

Head, Thorax, and Abdomen

The beetle’s body is divided into three main segments: the head, thorax, and abdomen. The head houses essential parts like eyes, antennae, and mouth.

Their eyes are large compound eyes, which allow them to see in various directions. The thorax attaches both wings and legs, while the abdomen contains the organs responsible for digestion and reproduction.

To better understand the differences between beetles, here’s a comparison table:

ColorLadybird beetlesRed with black spots
ShapeOval or elongatedUnique to each species
SizeTitanus giganteusOne of the largest beetles
LegsAttached to the thoraxSix jointed legs
WingsElytraHardened front pair to protect delicate hind pair
EyesCompound eyesImproved visual range
Body PartsHead, Thorax, AbdomenHousing essential organs and functions

As you explore the fascinating world of beetles, observe their incredible diversity in color, shape, size, and functional adaptations that make them successful in their respective environments.

stag beetle
Cottonwood Stag Beetle: The three sections of its body are clearly visible

Life Cycle of a Beetle

From Larva to Adult

The life of a beetle begins when it hatches from an egg and turns into a larva. These larvae, sometimes called “mealworms”, look very different from the adult beetles they will grow into, often appearing as white or tan grubs1.

They will later enter their pupal stage, transforming into adult beetles within their protective pupal cases. After emerging as adults, they become fully developed and ready to reproduce.

Reproduction and Eggs

When it comes to reproduction, adult beetles usually mate during the spring or summer. After mating, the females lay their eggs near food sources2.

Depending on the species, the number of eggs laid can vary, but females typically lay them in clusters. Over time, these eggs develop and eventually hatch within 7 to 10 days3, bringing new beetle larvae into the world.

Round Headed Borer Grub

Metamorphosis and Growth

As beetles grow, they experience a process called complete metamorphosis, which involves a dramatic change in their body form4. Throughout their development, they pass through four distinct stages: egg, larva, pupa, and adult.

The transformation from one stage to another is essential for the beetle’s growth and maturation. As larvae grow, they shed their exoskeleton multiple times before reaching the pupal stage, where the most dramatic changes occur.

Once they emerge from their pupal cases as adult beetles, they are ready to find a mate and start the life cycle anew.

Feeding Habits

Diet Variation

Beetles can consume a diverse range of food items, depending on their species. Some common foods in a beetle’s diet include plants, dung, fungi, carrion, worms, and aphids.

For example, many beetles, such as Ladybugs, primarily feed on aphids as their main food source.

Unique Eating Mechanisms

A beetle’s mouthparts are designed for various types of food consumption. Most beetles are equipped with chewing mouthparts, which allow them to break down their food with ease.

This helps with the digestion process. Some species have unique adaptations to feed on specific food items.

Here’s a comparison table to showcase feeding mechanisms of different beetles:

Beetle TypeFood SourceFeeding Mechanism
Dung BeetleDungRolling and Chewing
Saw-Toothed Grain BeetleGrainsChewing and Piercing

In summary, the feeding habits of beetles depend on their species. They can have diverse diets, consisting of plants, dung, fungi, carrion, worms, and aphids.

They can possess chewing mouthparts and other unique mechanisms that allow them to consume various types of food.

Habitats and Lifestyle

Ground to Air

In the beetle world, habitats can vary greatly. For instance, ground beetles live on the ground and play an important role as predators in most agricultural and garden settings.

These insects may be the most numerous predatory insects in certain ecosystems and can range in size from less than ¼ inch to over 1½ inches long1.

In contrast, some beetles are adapted for air, with hardened outer wings that give them an armored appearance2. These beetles can be quite different from one another, but both types play essential roles in the ecosystems they inhabit.

Beetles and Plants

Beetles have a significant impact on plants, as they feed by chewing2. They can cause damage to plants in the form of holes, notches, tunnels, and chewed plant parts.

For example, leaf beetles can decimate foliage, while wood-boring beetles tunnel through the wood of trees and shrubs.

Leaf Beetle

Beetles are also essential pollinators, especially for ancient plant species like magnolias and spicebush3. They tend to eat their way through petals and floral parts, which sometimes earns them the nickname “mess and soil” pollinators.

Desert to Forest

Beetles are incredibly diverse and can be found in a wide range of habitats. From deserts to forests, they have adapted to various environmental conditions2. In each of these habitats, beetles play unique roles:

  • Deserts: In arid environments, beetles are vital scavengers and recyclers, breaking down organic matter such as dead plants and animals.

  • Forests: In these lush ecosystems, beetles contribute to pollination, decomposition, and provide food for other animals.

Whether they’re in the dry dunes of a desert or the lush greenery of a forest, beetles play essential roles that help maintain balance in their ecosystems.

Defense Mechanisms

Camouflage and Poison

Beetles utilize various defense mechanisms to protect themselves from predators. One common method is camouflage, where beetles blend in with their environment to avoid being seen.

This can include mimicking the appearance of leaves, branches, or other natural elements.

For example, the soldier beetles are usually dark brown to black with orange, red, or yellow markings, which can help them blend in with their surroundings.

Another defense strategy they employ is the use of poison. Some beetles secrete toxic or irritating substances that deter predators.

The bombardier beetles, for instance, possess a remarkable defense mechanism where they release a hot chemical spray from the tip of their abdomen, producing an audible explosive sound.

The repellent properties of these chemicals have been found to be effective against various taxa.

Goldenrod Soldier Beetle: Perfect at camouflage

Sound and Taste

Beetles also use sound as a defense mechanism. The noisy response by the bombardier beetles mentioned earlier is an excellent example; the explosive sound created during their chemical spray release serves to startle and warn predators of their toxic defenses.

Taste is another factor that helps beetles ward off predators. Many beetles have a bitter taste due to chemicals they produce or consume, making them unpalatable to potential attackers.

The predators, such as birds and mammals, quickly learn to associate the bitter taste with beetles and avoid consuming them in the future, providing an added layer of protection for the beetle.

In conclusion, beetles have evolved a variety of defense mechanisms, including camouflage, poison, sound, and taste, to protect themselves from potential predators.

They often utilize multiple strategies to enhance their chances of survival and have proven to be quite effective in evading various types of threats.

What Do Beetles Do? Types of Beetles

Beetles in Depth

Beetles belong to the order Coleoptera and are one of the most diverse groups of insects. With thousands of species, they can be found in various habitats and serve different roles.

In this section, we’ll explore some common types and their characteristics.

Rove Beetles: You might be familiar with rove beetles as they are agile, fast-moving insects. They have elongated bodies and are known for their ability to raise their abdomens like scorpions when threatened.

If you come across a rove beetle, don’t take their threats casually – these beetles can give you a pretty solid bite as well. Rove beetles primarily prey on small insects and are found in various habitats.

What Do Beetles Do
Splendid Earth Boring Dung Beetle

Bark Beetles: These are small, cylindrical beetles that bore into the bark of trees, often causing damage.

Some species, like the Southern Pine Beetle, can even kill entire trees. They usually lay their eggs within the bark, and their larvae feed on wood fibers.

Leaf Beetles: As their name suggests, leaf beetles are known for feeding on leaves. Some species can cause significant damage to agricultural crops and garden plants.

One example is the Colorado potato beetle, which is considered a serious pest of potato and tomato plants.

Click Beetles: These beetles are named after the clicking sound they make when they jump.

They have a unique mechanism between their thorax and abdomen that allows them to snap their body, propelling them into the air.

This helps them escape predators and right themselves when they are upside down.

Some other beetle types you might encounter include:

  • Ladybugs or Lady Beetles: These insects are popular for their bright colors and spots, as well as their beneficial role in controlling pest populations like aphids.
  • Flea Beetles: Small and agile, they get their name from their ability to jump like fleas. They can be problematic for plants, as their feeding leaves small holes or pitting in leaves.
  • Scarab Beetles: This group includes a variety of species, such as dung beetles and Japanese beetles, that play important roles in ecosystems. Some, like dung beetles, are responsible for breaking down and recycling organic matter, while others can be garden pests.
  • Water Beetles: As their name implies, these beetles live in aquatic environments. Some species, like whirligig beetles, have fascinating adaptations, such as divided eyes that allow them to see both above and below the water surface simultaneously.

No matter what type of beetle you encounter, it’s important to understand their unique characteristics and roles in the environment.

Remember, while some may be considered pests, many others provide valuable benefits to ecosystems and humans alike.

Notable Beetle Behaviors

Bioluminescence and Scent Signals

Beetle species like fireflies and lightning bugs display an amazing phenomenon called bioluminescence.

These beetles produce light through a chemical reaction in their abdomen, which helps them attract mates and communicate with each other.

Besides lighting up, some beetles use scent signals to ward off predators or send messages to their peers. For example, bombardier beetles release a hot, noxious chemical spray to deter attackers.

  • Bioluminescent beetles: fireflies, lightning bugs
  • Scent signals: bombardier beetles
Bombardier Beetles use pheromones

Aquatic Adaptations

Did you know that a vast number of beetles are aquatic or semi-aquatic? These aquatic beetles have amazing adaptations to help them survive and thrive in their environments.

For instance, many aquatic beetles have considerably large and brightly colored bodies, which enable them to blend with their surroundings or use bright colors to signal danger to predators.

Some beetles have specialized structures to aid in breathing underwater. These beetles carry an air bubble beneath their bodies, allowing them to access oxygen while submerged.

In comparison, other aquatic beetles have modified structures on their limbs or abdomen to aid in propulsion through water.

Aquatic AdaptationsExamples
Bright colorsDiving beetles
BreathingWhirligig beetles
PropulsionPredaceous diving beetles

Your understanding of beetle behavior should be enriched by knowing their diverse adaptations!

Beetles and Humans

Beneficial Beetles

Predator Beetles: Beetles can be beneficial to humans, acting as natural pest controllers by feeding on other insects.

For example, ladybird beetles are important predators of aphids and can be purchased commercially for this purpose.

Decomposers: Beetles play a vital role in breaking down organic matter in forests, contributing to nutrient recycling in ecosystems.

Lady Beetle feeds on Aphids

Harmful Beetles

Pest Beetles: On the other hand, some beetles can be harmful to humans. For example, Tribolium confusum, T. castaneum, T. molitor, and other beetles are known to feed on crops or stored products and can significantly impact food supplies.

Wood-boring Beetles: Beetles like borers can cause structural damage to buildings by infesting wood materials in the United States and around the world.

Here’s a comparison table highlighting the benefits and detriments of beetles:

Predator of pestsCrop and stored product damage
Decomposes organic matterStructural damage to buildings

In summary, beetles interact with humans in various ways, both beneficial and detrimental. They play a crucial role in the animal kingdom and are an important part of invertebrate diversity in the United States and beyond.

Fascinating Beetle Facts

Did you know that beetles are the most common type of insect? In fact, they belong to the order Coleoptera, which constitutes the single largest group of animals on Earth! Let’s explore some interesting beetle facts.

Beetles are quite diverse in appearance, but many have elongated bodies and hardened outer wings. As they feed by chewing, you may observe holes, notches, tunnels, and chewed plant parts as a result of their appetite.

Pumpkin Beetle
A Pumpkin Beetle

You’ll find quite a variety of unique beetle species, displaying a wide range of colors, sizes, and shapes.

Some beetles, such as ladybirds, are known for their striking appearance and are actually predatory beetles. They help control pests like aphids and mites, which can wreak havoc on your garden or crops.

A fascinating aspect of beetles is their incredible sense of smell. They use their antennae to detect pheromones released by other insects and even sense moisture in their environment.

This is particularly useful for locating food sources, mates, and ideal living conditions.


Beetles have a deep-rooted history on Earth. Beetle fossils dating back around 230 million years reveal their ancient origins, and prove that they have played a crucial role in the ecosystem for a very long time.

Beetle pollination is especially significant for ancient species like magnolias and spicebush.

Overall, beetles are incredibly diverse insects with fascinating features like their sense of smell, elongated bodies, and roles in the Earth’s ecosystem.

Just remember, next time you encounter one of these intriguing creatures, there’s more to them than meets the eye!


  1. https://askabiologist.asu.edu/life-cycle 2

  2. https://www.fs.usda.gov/Internet/FSE_DOCUMENTS/stelprdb5349704.pdf 2 3 4

  3. https://askabiologist.asu.edu/life-cycle 2

  4. https://askabiologist.asu.edu/life-cycle

Reader Emails

Over the years, our website, whatsthatbug.com has received hundreds of letters and some interesting images asking us about beetles. Scroll down to have a look at some of them.

Letter 1 – What’s this beetle??!!

Hello: What’s this beetle??!! It was found in western Colorado near Grand
Junction. It’s about 45 mm long, dark brown, long antenna, see
pictures….. Thank you!

They are beautiful photographs of a California Prionus. See following letter for more details.

Letter 2 – Weevil Infestation

Subject: Infestation in insulation
Location: Ontario
July 17, 2013 12:59 pm
Mounds of little black bugs are littering the concrete floor around the inside walls of a cold storage room in the crawl space under my solarium attached to my 11-year old house. They are apparently infesting the sprayed-on foam insulation in the walls and are falling out, most dead, some still moving.

The two exterior walls of the cold room now have tiny black ants nesting in the insulation, and some make their way into my solarium. I’ve almost never used the cold room because it is too damp and ventilation is very inadequate.
I live in a wooded area in a little community on a small lake. It’s on a peninsula between Lake Huron and Georgian Bay in ontario.
Signature: Donna

Beetle Infestation
Weevil Infestation

Dear Donna,
Many small beetles that infest homes for various reasons look very similar.  We are requesting assistance with this identification.

Beetle Infestation
Weevil Infestation

Eric Eaton Responds
They are weevils of some kind, so they had to have originally fed on vegetable matter I believe….

Hi Again Donna,
Eric Eaton has identified your beetles as Weevils that feed on vegetable matter.  We cannot imagine what they were eating inside your walls.

Letter 3 – Warf Borer

Can you help identify?
Hi there, I have recently moved from the UK to central Boston and have found several of these flying insects in my city center apartment. Their bodies are generally 0.5 to 0.75 inches long. I am unsure if they are attracted by light or not. Thanks in advance
Mike Hume

Hi Mike,
We wrote to Eric Eaton to properly identify your beetle. He wrote back: “Ok, the beetle is the “Wharf Borer,” Nacerdes melanura. It is in the
family Oedemeridae, the False Blister Beetles.” Adults are usually found on flowers or foilage near water and the larvae live in decaying wood. It is common in woodsheds, cellars and lumberyards. Originally European, it has been spread around the world due to commerce.

Letter 4 – Watermelon Bug

Hello Mr. Bug Guy!
Never seen anything like it before and we have no idea how it got into the house and onto the second floor landing. That’s as far from any open window as it gets in our place and not close to the ground, either. (Although we do have two cats and a kitten.) It was casually walking, slowly, along the carpet. Actually, it looked kinda sick.

It wasn’t moving particularly fast or anything. We scooped it into a jar and within hours, there was barely a flicker of movement left. (Still Flickering, though, as I write this.) It’s not quite 3 cm from nose to tail. It’s coloring was much like a watermelon, the kind with a lot of contrast between the stripes. It had these two, strange paddles out front, looking a lot like shoehorns. Any idea what this bug might be? Is it local or some kind of import? I’m in San Jose, CA, at the southern tip of San Francisco Bay.

While cleaning out the old email account, we discovered these amazing photos sent in by John of a Ten Lined June Beetle, Polyphylla decemlineata. They are native and the adults eat pine needles while the grubs are considered pests of peach trees.

Letter 5 – We have Hundreds maybe Thousands on the ground…

We have Hundreds maybe Thousands on the ground and
all over our house. Please help us as my 6 and 4 year olds are scared and me too!

We were unable to anwer this reader who should be somewhat afraid of Blister Beetles which can cause a skin reaction.

Letter 6 – Western Pine Borer

Help identify Beetle!
Hello! First of all, I wanted to let you know that I really enjoyed looking at your website and all of the different beetles that were listed. It is really fascinating what people find around their homes. The pictures are fantastic. We live in Olympia, WA (Pacific NW) and recently found this beetle hiding on the shady side of a plastic container.

It is just a hair over 1 inch long. Its slow moving and has an irridescent pinkish sheen to it and large eyes. I have never seen one around here before and no one else seems familiar with it either. What is it? Thanks!

Hi Melinda,
This is a Western Pine Borer, Chalcophora angulicollis. It ranges from Alaska to New Mexico and west to California. Adults feed on foliage and larvae bores in firs and pines. This is one of the Metallic Wood Boring Beetles in the family Buprestidae.

Letter 7 – Whirligig Beetles in Tanzania

Tanzanian Beetles
Location:Ngorongoro Crater, Tanzania, East Africa
August 12, 2010 6:08 pm
Hi, Bugman!
While traveling in the Ngorongoro Crater in Tanzania, Africa in July I came across these beetles doing 360’s in a pond. Please identify what they are.
AJ aka photographer of the Puddling Caper Butterflies in Mali, Africa, November 2009

Whirligig Beetles

Dear AJ,
It was quite astute of you to recognize these aquatic insects as beetles.  They are in fact Whirligig Beetles in the family Gyrinidae, and we are quite excited because we believe this is the first image we have received from this family.  Whirligig Beetles can’t help but bring a smile to our face when we see them whirling rapidly in circles on the surface of a pond or slow moving stream.

August 13, 2010
We neglected to indicate that Whirligig Beetles are not limited in geographic range to Africa.  They are also found throughout most of North America and in other parts of the world as well.

Letter 8 – Xyloryctes species

big dead bug
I found this on my sidewalk Saturday. Any idea about what it is? I’ve never bumped into one of these before. We’re sending it to a friend of ours who’s an artist in Houston who makes clothing for dead bugs. No, really, I’m serious.Any ideas what this is?

Hi Sean,
We stand corrected. See below.

Hi, This is Steven from Beetle-experience. Hope things are going well. I think it’s been about a year since we last spoke. The site is looking good, tons of photos coming in of all those insects walking around out there.

Just came from a drive about an hour north of here where I found S. aloeus and D. tityus adults. I’ve also been finding Lucanus capreolus lately. I’m still looking for live Polyphylla specimens, if you can think of anyone to send my e-mail address to.

Sorry to mention: your photo listed as: “Strategus antaeus, (06/20/1005)” looks like a male Xyloryctes to me. It has that strongly bulbous prothorax and appears to have a curved horn without any side horns.
Xyloryctes: http://entweb.clemson.edu/museum/webonly/local/lmisc/lmisc17.htm
S. antaeus: http://entweb.clemson.edu/museum/webonly/local/lmisc/lmisc39.htm
Keep up the great work,
Regards, Steven
Ed. Note: Write to him at info@beetle-experience.com


  • Bugman

    Bugman aka Daniel Marlos has been identifying bugs since 1999. whatsthatbug.com is his passion project and it has helped millions of readers identify the bug that has been bugging them for over two decades. You can reach out to him through our Contact Page.

    View all posts
  • Piyushi Dhir

    Piyushi is a nature lover, blogger and traveler at heart. She lives in beautiful Canada with her family. Piyushi is an animal lover and loves to write about all creatures.

    View all posts
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1 Comment. Leave new

  • just found one of these in seattle of all places. our climate has changed so much locally that we are not surprised the flora and fauna would, too. if you email me back i’ll send a photo.


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