What To Know About Assassin Bugs

Updated: Jan. 18, 2024

A lot of insects feed on other pests, so what earns the assassin bug such a sinister name?

Sometimes, lying in wait, assassin bugs are known to stalk their targets using stealthy moves, lightning-fast speed and an element of surprise. Once they pounce on their prey, they stab them and release a paralyzing toxin that overcomes and kills the victim. And, If that wasn’t gruesome enough, then they suck their prey’s liquified innards through their straw-like mouthparts.

“While this sounds like something out of a horror movie, the fact is that most assassin bugs are actually beneficial! It is common to find assassin bugs in your backyard,” says Katelyn A. Kesheimer, Ph.D., assistant professor & extension specialist at the Alabama Cooperative Extension System, Auburn University.

Clearly, this bug is a grizzly menace to its prey, but are assassin bugs dangerous to humans, pets and the environment? Let’s find out.

What Is an Assassin Bug?

The assassin bug is a long-legged terrestrial (crawling) insect, considered a generalist predator that feeds on a variety of field, forest and crop pests.

A member of the Reduviidae family (with some 25 subfamilies), among the most common subspecies found in North America are the wheel bug, the ambush bug (lies in wait), the masked or bedbug hunter (eats bedbugs and bites) and the blood-sucking kissing bug.

What Do Assassin Bugs Look Like?

That depends on the subspecies.

In general, adult assassin bugs range from around 1/2 to 1-1/4 inch in length, have shield-like backs and are usually brown, black or gray — although some are colored to blend in with flowers. Marked by an elongated head with a thin neck and reddish eyes, they’re also characterized by their long, curved proboscis. “The proboscis is the straw-like beak that rests under their body when not in use. Assassin bugs can quickly engage their beak to feed on a prey item,” says Dr. Kesheimer.

Some distinct features of the different varieties are:

  • Wheel bug: Gray, large (1-1/4 inches long), with saw-toothed, semicircle crest on its mid-section.
  • Ambush bug: Yellowish green, 1/2 inch long or less, stocky body and thick, praying mantis-like front legs.
  • Masked hunter bug: Brownish-black, typically lives indoors where it can eat bed bugs.
  • Kissing bug: Cone-shaped nose and striped borders.

Egg-laying female assassin bugs are much larger than males and nymphs (juveniles) are smaller versions of their wingless adult counterparts.

Where Do Assassin Bugs Live?

Of the more than 7,000 assassin bug species worldwide, more than 160 of them live in North America alone. They live in urban, rural and mountainous areas, mostly in Arizona, California and New Mexico. They can also live further north because, unlike some bugs that can’t tolerate cold climates, adult assassin bugs are capable of withstanding harsh winters, surviving in sheltered locations, such as inside homes, dog houses and chicken coops.

What Do Assassin Bugs Eat?

The assassin bug has a varied diet that consists of small to medium-size insects and invertebrates such as beetles, spiders, bees, flies, caterpillars, worms, grasshoppers and crickets. Wherever tasty garden pests gather, assassin bugs are sure to follow.

Do Assassin Bugs Bite?

Yes, assassin bugs bite therefore it’s best to avoid handling them. A bite can be quite painful and could result in swelling and infection.

Wizzie Brown, BCE (Bachelor’s of Science in entomology) Extension Program Specialist at the Integrated Pest Management (IPM), Texas AgriLife Extension Service advises keeping a keen eye out for the presence of kissing bugs. “If you find this type of assassin bug in your yard, you would not want to keep them around since they are capable of transmitting Chagas disease.*

Signs you may have contracted Chagas include fever, fatigue, body aches or headaches. If you present any of these symptoms, however mild, after being bit by an assassin bug, it’s recommended you seek medical attention immediately.

*Note: According to the Center for Disease Control and Prevention (CDC), Chagas disease, if untreated, is a potentially life-threatening illness caused by the protozoan parasite, Trypanosoma cruzi, a microorganism that can be transmitted to humans and other mammals by triatomine (vector-borne) bugs carrying the disease.

Do Assassin Bugs Cause Damage or Are They Beneficial?

As noted before, some assassin bugs can be highly beneficial to maintaining the eco-balance in your garden, killing plant-destroying aphids, leaf-munching caterpillars and the like.

To encourage “good” assassin bugs to stick around:

  • Plant flowers, vegetables, shrubs and trees that draw assassin bug food sources.
  • Avoid spraying pesticides.
  • Allow assassins to find places to overwinter.
  • If you find non-kissing bugs inside, scoop them up and return them to the garden.

How To Get Rid of Undesirable Assassin Bugs

“An important distinction to make here is that all kissing bugs are assassin bugs but not all assassin bugs are kissing bugs,” says Kesheimer

Should you encounter kissing bugs in your backyard, garden or field, the following are all good management strategies for keeping them (and other unwanted insects) outside:

  • Fill holes and cracks in foundations and seal gaps around windows and exterior doors, so the bugs can’t get inside.
  • Keep pets indoors at night but avoid allowing them to sleep in bedrooms.
  • Clean pet beds frequently.
  • Keep woodpiles, organic debris, tree branches and animal cages away from the house.
  • Turn off outdoor lights at night to avoid attracting bugs.

If you find kissing bugs in the house, it may be time to call a pest management professional to administer treatment. “For chemical control, the chemical class pyrethroids are effective against kissing bugs.” says Kesheimer.

Note: These insecticides can be harmful to humans and pets, so work with the pest control company to ensure your safety.