Wheel bug



The wheel bug is a medium-sized bug living in the United States. They have been spotted as far west as New Mexico and as far north as Massachusetts. Almost all of the states in between these two, going as far south as Florida, have had wheel bug sightings. They have also been seen in a few Canadian provinces (at least Ontario and Quebec). As you might be able to tell, in the picture above, the bug has a spiked half-circle behind its head. This circle or  wheel is where the wheel bug gets its name. This insect is a type of assassin bug, and while a wheel bug does not sound very dangerous, an assassin bug does. The wheel bug is dangerous by the way. Despite being dangerous, it may actually be a good bug to have in your garden.


Not including their antennae, these bugs range from one to one and a half inches (2.5-3.8 cm). The wheel bug is the largest species in the assassin bug family.


Wheel bugs are carnivores, and eat mainly other insects. These insects include garden pests such as caterpillars, aphids, and Japanese beetles. In order to attack their prey, wheel bugs will slowly sneak up on their victim. Once it gets really close, the wheel bug will grab on to its victim using its front legs. The victim will then be pierced by the wheel bug’s tube-like mouth part. This mouth part is often called the proboscis or the rostrum. The rostrum will secrete a venom into the victim. This venom paralyzes the victim in a few seconds and starts digesting the prey’s insides. The wheel bug will then be able to eat bug soup through its straw-like mouth.

How they affect humans

Wheel bugs affect humans in good and bad ways. Good ways include killing pests that can cause major damage to gardens. They should be avoided however because they can deliver a nasty bite. Although they move very slowly and are not aggressive, if bothered, a wheel bug will bite. Their bites are described as ten times as painful as a hornet sting. The pain is said to last several minutes and the wound may take weeks or even months to heal. Bites should be cleansed with soap and water, and lotions with menthol, phenol, and camphor may provide relief from the pain. Although wheel bug bites are not deadly and do not cause any permanent damage, I would not recommend trying to touch one.

Predators and protection

Even predators have predators. Although these animals are top predators in the insect world, they are seen as prey to many other animals. Such animals include small birds, mammals (such as mice), reptiles (such as lizards and snakes), amphibians (such as large frogs, toads, and salamanders), and fish. Wheel bugs can use their rostrum as a weapon to bite an attacking animal, and deter it from attacking. These insects can also secrete a nasty smelling/tasting liquid that will repel some predators. Wheel bugs also (as with most insects) have a hard outer shell that may keep them from becoming a meal for another animal.

Mating and eggs

Male and female wheel bugs mate in the fall. After mating, the females will lay hexagon-shaped clusters of eggs on solid objects such as trees. The eggs, which are brown, are small and cylindrical. Each female lays from forty to two hundred of these. The females die after laying the eggs. Adult wheel bugs cannot survive the winter, but the eggs can.


In the spring, the eggs hatch to reveal young wheel bugs that look nothing like the adults. These young wheel bugs are called nymphs. As you can tell from the picture on the left, wheel bug nymphs have a red abdomen and the rest of their body is black. Adults on the other hand are completely gray. Another difference is that the young wheel bugs do not have the gear-like structure on their back. Despite their difference, the nymphs are still deadly predators like their parents. These young wheel bugs will molt around five times before they become adults. After their last molt, they will finally look like the wheel bug in the picture above.

Don’t forget to scroll down and comment your guess about what the next animal is!



Photo credits:

  • Wheel bug -Public domain
  • Wheel bug nymph – Derek Ramsey
  • Mystery animal – J. Patrick Fischer

2 Responses

  1. Largetooth sawfish
    Largetooth sawfish at |

    […] by humans. Their saw-like snout or rostrum (Last weeks animal had a rostrum too! Read about it here!) often gets entangles in fishing nets. Even if the fishermen do not mean to catch the sawfish, […]

  2. Charis
    Charis at |

    It seems like its name should be the hedge trimmer shark! 🙂

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