Assassin Bug: The Kind of Insect You Want in Your Garden

Welcome the insects that eagerly gobble up the pests that prey on your favorite plants.

By Glenda Taylor and Nina Malkin | Updated Mar 8, 2021 5:53 PM

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What Are Assassin Bugs? All You Need to Know About These Beneficial Bugs


The insect realm is rife with creepy-crawlies, be they smelly stink bugs, sneaky weevils, or simply slimy cockroaches. Yet certain bugs are capable of wreaking havoc in the garden, destroying harvests and stripping colorful blooms. If you spend time and money using chemical insecticides to banish bugs, you’ve probably learned to spot such culprits as aphids, squash bugs, and tomato worms—but you might not know about beneficial insects that prey on these pests. Like characters in an espionage novel, there’s a whole class of assassin bugs lying in wait to wallop destructive insects. Keep reading to learn all about them!

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What is an Assassin Bug?

Commonly called assassin bugs, these bad boys of the insect world belong to a large group in the Reduviidae family. Though there are approximately 160 different species of assassin bugs in

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North America, and more than 3,000 worldwide, they all share one notable characteristic: a curved, dagger-like mouthpart known as a rostrum or proboscis, which is used to kill prey. An assassin bug will spear its victim, inject lethal venom or digestive juices to kill it, and then suck on the prey to feed. They also use this beak to defend themselves from predators.

Assassin bugs of the Reduviidae family are also sometimes familiarly referred to as kissing bugs—and for their prey, it’s the kiss of death! They devour the likes of destructive aphids, leafhoppers, and caterpillars, and can even consume insects larger than themselves. What’s more, kissing bugs actively hunt their prey, patrolling trees, bushes, and other vegetation for victims. No wonder experienced gardeners view them as friends, especially those who take a natural approach and like to limit their use of pesticides.

Characteristics of Assassin Bugs

If you’re wondering if assassin or kissing bugs are present in your garden, here are some of their most identifiable characteristics:

  • Their most obvious aspect is the rostrum, a sharp, three-segmented, hollow beak.
  • As adults, their body can range from about ½ to 1¼ inch in length.
  • Many are brown, gray, or black, although some are brightly colored or have bright red, orange, or green areas on their bodies.
  • They have round, beady, protruding eyes that help them spot prey
  • They have a long, narrow, tubular head that gives them the appearance of having a neck.
  • Their legs tend to be longer than those of many other insects.
  • While they have wings and can fly, they tend to be poor flyers.
What Are Assassin Bugs? All You Need to Know About These Beneficial Bugs


Identifying Species of Assassin Bugs

With so many kinds of assassin bugs, they are often confused with other invertebrates that are not a gardener’s friend. When scouting your landscape for hungry helpmates, consider these clarifications to know what is—and isn’t—an assassin bug.

The Wheel Bug: the Most Common Assassin

The most common and readily recognizable assassin is the wheel bug. At 1¼ inch in length, wheel bugs are the largest species in North America, gray in color and sporting a raised semi-circular crest on its back that resembles a wheel with protruding spokes. Dr. Michael J. Raupp, entomologist at the University of Maryland, dubs the wheel bug “the lion or the eagle of your food web,” and calls their presence evidence of “a very healthy landscape.”

Ambush Bugs: a Type of Assassin

One type of assassin bug is the ambush bug, which has a stouter body that’s typically bright yellow, red, or orange. They also have thicker front legs that they use to help capture and hold down prey. Yet while assassin bugs actively hunt on different types of vegetation, ambush bugs tend to sit among flowers and wait for victims to come their way.

The Western Conifer Seed Bug vs. the Assassin Bug

Though it looks similar to the wheel bug, the western conifer seed bug (WCSB for short) is a species of true bug and a member of the Coreidae family. It makes a buzzing noise in flight and can emit a noxious odor, like a stink bug. It feeds primarily on resinous plants, particularly the sap of developing conifer cones.

The Leaf-Footed Bug vs. the Assassin Bug

The leaf-footed bug is the common moniker for insects in the family Coreidae. While they have the piercing and sucking mouthparts that assassin bugs do, leaf-footed bugs, in both their nymphal and adult life stages, damage plants, feeding on juices from leaves, shoots, stems, and fruit. Leaf-footed bugs can ravage the likes of vegetables, citrus, and row crops, as well as ornamental plants and weeds.

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What Are Assassin Bugs? All You Need to Know About These Beneficial Bugs


The Assassin Bugs Habitat

With 3000 species of assassin bugs, it’s no surprise to learn that their habitat is pretty vast. Assassin bugs can be found everywhere from rain forests to rocky areas, though many species thrive in moist environments. You may spot them around your property in wood piles, animal nests, and chicken coops.

In terms of vegetation, assassin bugs range freely and, except for ambush bugs, which are drawn to flowers, they don’t prefer any particular type of plant. They’re found in orchards, vegetable gardens, ornamental flowerbeds—virtually everywhere their prey may be. That’s why they’re so beneficial for natural pest control. If you have a garden, even a small one, or a few outdoor container plants, odds are assassin bugs will come to dine.

Assassin Bug Life Cycle

While the incubation time of eggs and metamorphosis of nymphs (immature bugs) differs among species, many assassin bugs in North America breed in autumn. The female deposits clumps of fertilized eggs under leaves, on stems, and in the crevices of plants. The eggs overwinter and then hatch into wingless nymphs the following spring. Nymphs undergo several growing stages, each one accompanied by the shedding of skin (molting). By summer, the assassin bug will have grown wings and reached adulthood.

Assassin bugs are resilient—nymphs, adults, and eggs can all survive temperatures below zero. Assassin bugs are capable of living several years.

Assassin Bug Hunting Strategies

Assassin bugs have voracious appetites and are almost always on the prowl. These adept predators may also use ploys to attract victims, such as coating their forelegs with sap or leaving the carcass of a dead bug as bait to lure a live one. Other times, the assassin bug will hide under a rock or piece of bark, creep up on its victim, then quickly snatch it with its front legs, which in some species have sticky hairs that help snare prey. Bright-colored ambush bugs are a bit lazier. Blending in with flower petals or leaves, they lie in wait for prey to approach, then go in for the kill.

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Next, the assassin bug pierces the body of its prey with its needle-sharp proboscis and injects a toxin that kills within seconds. The toxin also liquefies the insides of the victim, which the assassin bug sucks up through its hollow rostrum. When done feeding, it leaves behind just an empty shell. Assassin bugs can also use their long rostrums in self-defense, stabbing enemies such as birds and even squirting venom as far as an inch.

What do Assassin Bugs Eat?

Assassin bugs have a highly diverse invertebrate diet, feasting on everything from tiny aphids to large caterpillars and just about any bug in between. Thanks to the way they slurp up nutrients through the rostrum, they can finish off a much bigger bug with ease.

Assassin bugs are such indiscriminate killers, however, they’re just as apt to go after other beneficial insects. This means the bees that pollinate and lady beetles (also known as ladybugs) that feed on small destructive insects can also become prey in the garden.

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Are Assassin Bugs Poisonous or Dangerous?

Beware the assassin bug! Beneficial as they may for protecting your garden plants, these critters may attack and bite humans and animals, even if unprovoked, piercing the skin with that sharp beak. Though painful and likely to cause swelling at the site, for the most part an assassin bug bite rarely requires medical attention.

There are exceptions, however. Some species of assassin bugs may transmit Chagas, an inflammatory, infectious disease that, left untreated, can lead to heart and digestive problems. While Chagas can come from a kissing bug bite, according to the Centers for Disease Control and Prevention, it’s most often transmitted through exposure to the bug’s feces or through the blood transmission of an infected person.

If you notice an assassin bug on your body or clothing, flick it off sideways to remove it. Smashing it almost guarantees you’ll receive a painful bite for your efforts.

assassin bug on twig


Help Assassin Bugs Help You in the Garden

Assassin bugs can be a natural gardener’s best friend, controlling detrimental insects without chemical pesticides. To help them help you, try these tips:

  • Illuminate your outdoor space. Many assassin bugs are attracted to light.
  • Provide an oasis. Put some small stones or gravel in a small pan, and half-fill it with water. This way, assassin bugs can perch on the rocks to drink water without falling in and drowning.
  • Add mulch. Some assassin bugs are on the shy side and seek cover. Mulch offers them a place to hide out.
  • Kill carefully. If you must use pesticide to combat a particular infestation, choose a narrow-spectrum pesticide designed to kill only a specific type of insect. A narrow-spectrum pesticide that kills only ants, for example, won’t harm assassin bugs.
  • Fill in with flowers. Some assassin bugs are attracted to flowers, so entice them into a veggie patch by planting a few prolific bloomers like marigolds or tansy among the rows of cucumbers and peppers. Herbs such as fennel and dill may also tempt assassins.

Final Thoughts

Assassin bugs are a great way to control destructive insects without chemical pesticides. Now that you’ve learned to distinguish them—and how to attract them—welcome them to your garden and let them eat their fill. Just be sure not to mess with them or you could get a painful bite!