24 Types of Water Bugs (With Pictures)

Water bugs are a fascinating group of insects that have adapted to aquatic environments around the world. Ranging in size, color, and shape, these bugs play important roles in freshwater ecosystem food chains.

In this article, we’ll explore 24 of the most common types of water bugs found in North America and around the world. Understanding their key characteristics, habitats and behaviors will help you identify them near ponds, streams and lakes.

What Are Water Bugs?

Water bugs are from the order Hemiptera, known as the “true bugs.” They have piercing mouthparts and hardened forewings called hemelytra.

Unlike beetles, water bugs have incomplete metamorphosis with egg, nymph, and adult stages. Nymphs resemble small wingless adults.

Water bugs live on the water’s surface, right below it, or dive to find food Their middle and hind legs are adapted for swimming Many breathe underwater through respiratory tubes.

While some live exclusively in water, others are semi-aquatic and found both on land and in the water. A few occasional invaders can be found indoors around plumbing fixtures.

Common Physical Features

Water bugs share some similar physical traits:

• Elongated oval-shaped bodies
• Long antennae
• Three segmented piercing-sucking mouthparts
• Legs adapted for swimming

Their coloration helps them camouflage. Shades of brown, black, and grey predominate, some with yellow or red markings.

Size varies widely, from a 1⁄2 inch to giants over 4 inches long!

Habitats and Diets

Though found on every continent except Antarctica, water bugs prefer warmer regions. Most live in freshwater ponds, lakes, slow streams, and marshes with abundant vegetation.

Some species are predatory and feed on small fish, tadpoles, snails and insects. Others are scavengers. A few are vegetarians, eating algae and plant materials.

Now let’s look at 24 fascinating water bugs you might encounter near freshwater.

1. Giant Water Bug

The giant water bug (Lethocerus americanus) is the largest common water bug in North America, often called a “toe biter.” Growing over 2 inches long, they will bite in self-defense if handled.

These predators feed on insects, snails, worms, tadpoles and small fish. They pierce prey with needle-like mouthparts and inject saliva that liquefies the body contents for easier feeding.

A dark brown oval body helps them blend into muddy bottoms where they wait to ambush prey. The front legs act as pinchers to grasp food. They get oxygen from tubes extending from their abdomen.

2. Water Boatman

The water boatman’s oval brown body is covered in dense hairs that trap air bubbles, allowing it to float on the water’s surface. It uses its long oar-like rear legs to propel through the water.

Though only 1⁄2 inch long, the water boatman will eat mosquito larvae and other small insects. It dives underwater to find food, carrying a bubble of air to breathe from.

3. Water Striders

Often seen skating and jumping across the water’s surface, water striders have long hydrophobic legs that keep them from sinking. Tiny hairs on their legs trap air bubbles to provide buoyancy.

These dark colored bugs grow less than 1⁄2 inch long. They prey on insects and spiders unlucky enough to fall into the water. Their quick movements make them difficult for fish and birds to catch.

4. Backswimmers

Backswimmers get their name from swimming upside down near the water’s surface. Their long oar-like hind legs provide propulsion.

Growing just over 1⁄2 inch, they come in a variety of colors like grey, brown or reddish-orange. Backswimmers will bite if carelessly handled.

A voracious predator, they eat small insects, crustaceans and fish larvae. Like other water bugs, they carry an air bubble for breathing when diving.

5. Creeping Water Bugs

This aptly named bug creeps along the bottom of slow-moving streams and ponds stalking prey. Growing 1-2 inches long, they come in brown, yellow and black color variations.

The creeping water bug pokes its breathing tube above the surface while patiently waiting to ambush small fish and insects. It will play dead to avoid predators.

6. Giant Water Scavenger Beetle

Growing over 2 inches long, the giant water scavenger beetle is the largest aquatic beetle in North America. This voracious predator will eat anything it can catch including fish, tadpoles and frogs.

They are excellent fliers and sometimes attracted to lights at night. Their dark black bodies have yellow dotted lines down the abdomen. The larvae have large feathery gills on their abdomen.

7. Water Scorpion

Despite its frightening name, water scorpions are harmless to humans. Their flattened, elongated bodies grow 1-2 inches long. The front legs act like pincers to tightly grasp prey like aquatic insects and minnows.

They get oxygen through a breathing tube extending from their rear abdomen. Able to fly, water scorpions are found in marshes, ponds and slow streams across North America.

8. Predaceous Diving Beetle

Don’t be fooled by their small 1⁄2 inch size, predatory diving beetles are fierce hunters underwater. They dive down and grab small fish, tadpoles and aquatic insects.

Equipped with hind legs like paddles, they swim quickly in pursuit of prey. Most have dark colored bodies with lighter colored spots and edging.

You might find them clinging to the bottom in shallow water. They get air by trapping bubbles under their wings.

9. Water Scorpion

Water scorpions are true bugs, not a relative of scorpions. They get their name from their resemblance to land scorpions when they hold their front legs upraised.

These slender bugs grow 1-2 inches long with flattened, elongated bodies. They wait motionless for prey to come within reach of their front clasping legs.

Able to fly, they are common predators in ponds and slow streams across North America. They can deliver a painful bite but are not poisonous.

10. Giant Water Bug

Not to be confused with the giant water beetle, giant water bugs are true bugs reaching 2 inches long. They are voracious predators that will bite fish, tadpoles and aquatic insects in two with their beak-like mouth.

Growing up to 4 inches long, they are the largest true water bugs. They lay in wait for prey sneaking up to grab it with their front pincher-like legs. Their bite is painful so handle with care!

11. Water Boatman

The water boatman uses its hind legs as oars to row along the water’s surface. Dense hairs trap air bubbles keeping it afloat. Though only 1⁄2 inch long, it is a fierce predator of mosquito larvae and other small insects.

They dive below the surface to hunt but must return regularly for air. These common pond bugs are food for fish and amphibians. They can deliver a nip but are not poisonous.

12. Water Stick Insect

This delicately thin brown bug blends into submerged sticks and vegetation making it hard to spot. Growing 1-2 inches long, it slowly stalks prey including small fish, tadpoles and aquatic insects.

Its front legs act like pincers to grasp prey. Despite its frightening appearance, it does not deliver a painful bite and is harmless to humans.

13. Water Treader

Named for their ability to walk on water, these tiny 1⁄4 inch long bugs are common pond and stream inhabitants. Dense hairs waterproof their legs and trap air bubbles.

Though tiny, they are predators and scavengers feeding on anything edible they encounter from dead insects to plant materials. If threatened, they’ll fall below the surface or play dead.

14. Lesser Water Strider

Smaller relatives of giant water bugs, lesser water striders grow under 1⁄2 inch long. They are covered in microscopic hairs that repel water, allowing them to skate across the water’s surface preying on any unlucky insect that falls in.

These speedy bugs are difficult for fish and birds to catch. Often found in large groups, they can create ripple effects on calm waters. Their bite is harmless to humans.

15. Water Measurer

The water measurer takes its name from the way it stretches out atop the water’s surface to resemble a measuring stick. Growing 1-2 inches long, this stick-like bug has an elongated slender body.

It eats small insects unlucky enough to fall into the water. When diving below the surface, it carries a bubble of air to breathe from. Though creepy looking, it poses no threat to humans.

16. Giant Backswimmer

Reaching 1 inch long, giant backswimmers are predatory insects eating anything small enough to capture like mosquito larvae and tiny crustaceans. They get their name from swimming upside down near the surface.

Their hind legs act as oars propelling them after prey while their front legs grasp food. Air bubbles trapped beneath their wings provide oxygen for underwater hunting.

17. Water Scorpion

Despite its name, the water scorpion isn’t a scorpion but a true bug reaching 1-2 inches long. It grasps prey including small fish, snails and insects using its front pincer-like legs.

The breathing tube extending from its rear allows it to hide underwater awaiting unsuspecting prey. They prefer warm calm waters and can deliver a nip if handled.

18. Giant Water Bug

Among the largest true water bugs, giant water bugs grow 1-2 inches long. Voracious predators, they ambush tadpoles, small fish and aquatic insects, stabbing them with sharp mouthparts that inject digestive fluids.

They’ll inflict painful bites if carelessly grabbed. Look for them clinging to the bottom in shallow weedy areas where they await prey. They’re common in ponds across North America.

19. Water Boatman

The water boatman uses its hind legs as oars to propel across pond surfaces. Dense hairs trap air bubbles keeping it afloat. Just 1⁄2 inch long, they eat mosquito larvae and other small insects.

When diving for food, they carry an air bubble to breathe from. Though small, they can deliver a nip if handled roughly. They are common pond inhabitants worldwide.

20. Giant Water Scavenger Beetle

As their name suggests, giant water scavenger beetles grow very large, reaching over 2 inches long. They eat anything they can catch including insects, mollusks, fish and amphibians.

Equipped with paddle-like legs, they swim quickly in murky bottoms stalking prey. Attracted to lights, they sometimes invade swimming pools at night but are harmless. Larvae have feathery gills and live underwater.

21. Water Mite

Microscopic bright red water mites are often seen swarming together in stagnant waters. Only growing 1/50 of an inch, they stick onto passing animals like frogs or salamanders to hitch rides.

Larval mites attach to aquatic insects like mosquitoes to help disperse them to new waters for breeding. Though small, water mites play a role in aquatic ecosystems.

22. Lesser Water Boatman

The lesser water boatman is a tiny relative of the larger water boatman, only growing 1⁄4 inch long. It swims along the surface using its hind legs as oars to propel it.

A voracious predator despite its small size, the lesser water boatman injects saliva into prey to liquefy their insides for easier feeding. Look for them in ponds and marshes across North America.

23. Water Fleas

Though called fleas, these microscopic animals are actually small crustaceans just 1⁄30 of an inch long. They dominate freshwater zooplankton supporting fish and amphibian food chains.

Water fleas use large antennae for swimming and feed on green algae and plant debris. Predatory fish are constantly feeding on these abundant “fleas.”

24. Whirligig Beetles

Found across North America, whirligig beetles swim rapidly in circles on the water’s surface when alarmed. Growing 1⁄2 inch long, their divided eyes help them spot prey above and below water.

They eat insects, small fish and dead organisms. To breathe, whirligig beetles trap air bubbles beneath their wings and legs. Their dark rounded bodies often have yellowish dots and markings.

Well that covers some of the most common water bugs you’re likely to come across. As you explore ponds and streams, keep an eye out for these amazing insects uniquely adapted for life on and under the water.