What Do Harlequin Beetles Eat? Why Are They Considered Pests?

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What do Harlequin Beetles eat? This article explores their diets, habitats, and how you can get rid of these plant pests.

As the name suggests, Harlequin Beetles are a type of colorful beetle found in the United States, all the way up to Uruguay.

These beetles feed on common garden plants (and are not picky eaters at all), causing considerable damage, despite their dwindling population.

While you can easily get rid of them with some soapy water, let’s delve deeper into what these tiny bugs are.


What Do Harlequin Beetles Eat


What Are Harlequin Beetles?

Harlequin beetles (Murgantia histrionica) are a type of longhorn beetle found in parts of the American continent.

While they were originally found along the coasts of the Atlantic and the Pacific Ocean in North America, they soon spread out further south into Mexico and Uruguay.

Their names come from the distinctive coloration that both sexes exhibit. Both sexes have wings that sport shades of metallic green, greenish-yellow, bright red, and black patterns.

They can grow up to 3 inches in length and have exceptionally long forelegs. These forelegs can be longer than the entire length of the beetle’s body!

Males have larger legs (a type of sexual dimorphism) with a curvature at the front that helps distinguish them from females – the latter having shorter legs with no front curvature.

Males that have longer legs typically also have better reproduction abilities. These legs help guard the female during copulation and protect them from other predators and beetles.


Cotton Harlequin Bug


What Do They Eat?

Harlequin beetles are vegetarian and feast on most types of fresh vegetable plants. They attack common garden plants such as corn, tomato, and asparagus.

A species’ favorite seems to be planted in the Brassica family (cabbage family). This includes vegetables like broccoli, cauliflower, turnips, radish, cabbage, and more.

Because of the avid rate at which these beetles destroy plants, they are considered major garden pests.

These common pests feed by sucking out the plant sap, which destroys not only the fruits and vegetables but the plant itself.

The beetles inject a secretion into the host plant, liquifying its insides. They then suck on the plant juices. These insect pests can attack all parts of your plant, from roots to stems to veggies.

Young plants can die, and older plants can end with stunted growth. Adult harlequin bugs usually emerge during spring.

However, even the harlequin beetle larvae can cause considerable damage to plants. Infected plants will have discolored spots on them and eventually turn brown.


Harlequin Bug Nymph


Are Harlequin Bugs Harmful To Humans?

Harlequin beetles are not dangerous to humans (the same cannot be said for plants).

They are vegetarian and do not feed on flesh or other insects.

Moreover, they are not poisonous, and to date, there is no instance of them carrying or infecting humans with pathogens.

However, they have strong mandibles, characteristic of the beetle family. On facing danger, they can use this to clip onto the skin, which can be painful.

Sometimes, harlequin beetles can be carriers for some species of pseudoscorpions, which one should beware of.


Immature Harlequin Stink Bugs


How To Get Rid of Harlequin Bugs?

Large populations of harlequin beetles can damage your crops. Here are some measures you can take to control or eradicate their numbers:

  • Opt for vegetables that are resistant to these beetles.
  • Harlequin beetles are native to rainforest regions and thrive in bushy areas and plant debris. They are tree-dependent for their life cycle, hence keeping your garden well-weeded and clean will discourage beetle growth. You can also remove existing eggs from your plants by checking the underside of leaves and stems. If you find any harlequin bug eggs, kill them by drowning them in a soapy mixture or warm water.
  • You can use insecticidal soap on your plants that are already infected. These insecticides remove the exoskeleton of the beetle, which will eventually cause them to die due to dehydration.
  • An organic way to drive them out is to use onion or garlic-based sprays. The smell deters beetles.

Bug Control Recommendation Tool

What type of pest are you dealing with?

How severe is the infestation?

Do you require child/pet/garden safe treatments (organic)?

Are you willing to monitor and maintain the treatment yourself?

Harlequin Flower Beetle


Having said this, the harlequin beetle population is slowly dwindling due to deforestation and natural predators.

The IUCN classifies their conservation status as ‘Vulnerable.’

Due to their interesting wing patterns, they are kept as pets and often collected by connoisseurs for taxidermy and display.

Frequently Asked Questions

What does the harlequin bug eat?

The harlequin bug is a herbivore, and it prefers to feed on the leaves of cruciferous plants.
It primarily feeds on cabbage, broccoli, kale, turnip, kohlrabi, collards, Brussels sprouts, mustard greens, and radishes.
This pest also loves flower petals such as nasturtiums and marigolds.
The adults feed by sucking juices from tender foliage using their piercing-sucking mouthparts, while nymphs often eat through the crusty cuticles of larger leaves, leaving white patches.

Can harlequin beetles fly?

Harlequin beetles cannot fly due to the structure of their bodies.
The Harlequin Beetle has a large body and short wings, which would not provide enough lift for them to take flight.
They are, however, very good climbers, thanks to their strong legs and grip-like claws on their feet.
Furthermore, the Harlequin Beetle is light-sensitive, so it can be seen living in forested environments alongside other types of deadwood-dwelling insects.

What do harlequin beetles do?

Harlequin beetles are from the Longhorn beetle family and are known for their unique color patterns.
The Adult harlequin beetle has colorful scales that look like black, yellow, red, and blue painted glass.
The bright colors of these beetles may be intended to provide protection from predators or to attract mates.
They vary in size depending on the species but range from about 0.4 inches (1 cm) in length.
Harlequin beetles live around Europe, Asia, and North Africa and eat the leaves of willow trees, sweet gum trees, and tulip trees.
During their development, they also consume decaying wood and fungi that grow on the bark of these tree species.

How long do harlequin beetles live?

Harlequin beetles typically live for 1-3 years, depending on the species. During this time, they should have ample opportunity to mate and reproduce.
Typically, Harlequin beetles spend part of their life in their larval stage before morphing into adults.
In some species, they hibernate during the winter months, while in others, they remain active throughout the year, though some may enter dormancy during periods of extreme weather.

Wrap Up

Due to their appearance, people often mistake them for stinky bugs.

They are also distinct from the Harmonia axyridis or the harlequin ladybirds, which are ladybird beetles found in the UK isles.

But once you get familiar with their strange coloration, it’s hard to mistake them for anything else. Thank you for reading.


  • 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.

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  • 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.

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