What Bugs Are Red and Black?

What Bugs Are Red and Black?

If you’ve encountered red-and-black bugs crawling around your home, there’s a good chance they are boxelder bugs. While looking for shelter during the winter months, boxelder bugs often end up inside homes in large numbers. These insects are considered nuisance bugs in residential areas. Not only do they invade en masse, but they also release an off-putting smell when stepped on, and their blood can stain surfaces. Find out more about these pests, and what to do when you spot them.


The boxelder bug (Boisea trivittata) received its name because it mainly feeds on the seedpods, leaves, and flowers of female boxelder trees. However, in some areas, these insects are also called maple bugs because they can be found on maple, ash, or fruit trees. These red and black bugs are about ¾” long and have three distinct stripes below the head. Red markings outline the wings as well. 


Boxelder bugs lay small, red eggs in boxelder trees during the spring. These eggs hatch after a few days into bright red nymphs. Boxelder nymphs continue to develop until they reach adulthood in the summertime when they begin to reproduce. Until they reach adulthood, nymphs maintain a bright red thorax with yellow/orange stripes and small black wings. 

Like many insects, when winter approaches, boxelder bugs seek shelter to preserve their energy. This process is called overwintering. They usually shelter in the hollow of a tree or under rocks or other debris. But in areas with large boxelder populations, these bugs also seek shelter in nearby buildings.


Boxelder bugs have distribution all over the United States and Canada, but they are more common in regions with a lot of boxelder, maple, and ash trees like Minnesota, Oregon, and Vermont.

During the summer, they live on their preferred trees so they have a continual food source and may be seen flying for several blocks. They also choose boxelder and other trees as a place to lay their eggs so their offspring have a place to eat as well. 

In the fall and winter, boxelder bugs live in the hollow of a tree, under rocks or other debris, or inside buildings. They’re most likely to seek shelter in attics, wall voids, and other covered areas.


Many people think these red-and-black bugs end up in your home because they’re looking for warmth in the winter. However, it’s quite the opposite. Although boxelder bugs bask in the sun during warmer months, like all insects they are cold-blooded and need to stay cool in order to preserve energy. The reason they seek shelter in the winter is to avoid the elements and harsh weather. 

When boxelder bugs look for a place to overwinter, they often make their way into buildings through cracks and crevices in walls, doors, and windows. Erroneously, they assume they’ve found a cool shelter from the elements, not realizing that homes are heated in the winter. 

When heaters kick on during winter months, these bugs wake from their dormant state confused and begin scrambling around, thinking the seasons have changed. This is why you might suddenly see a swarm of red-and-black bugs in your home in the fall, winter, or spring. 

If they have indeed woken up during the winter, boxelder bugs will not be able to survive after a few days indoors because they won’t be able to find food and will burn up all their energy reserves.


Boxelder bugs are not poisonous and are not known to carry disease, but they do leave stains when crushed and can emit a foul odor when threatened. If your dog or cat happens to eat a few of these insects, they may feel sick and will probably experience a nasty taste because of the chemicals boxelder bugs release. 


These insects feed exclusively on plants and plant materials, so within the home, they won’t typically seek out human or pet food. If you have a large population of boxelder bugs outside, they may begin to encroach on your lawn and cause damage to your grass and other plants. This bug can become an issue around orchards of fruit trees as they may partially feed on the fruit and damage it. 


Boxelder bugs are not predatory creatures, but they have been known to bite when handled in some instances. If you have an invasion of these red and black bugs in your home, don’t attempt to handle them because they may feel threatened and decide to bite. 


If you have an infestation of boxelder bugs in your home, it can be difficult to try and remove these red-and-black bugs by yourself. Not only are they prolific, but they also produce unfriendly odors and bright yellow liquids that can stain your carpet and walls. 

The best way to get rid of boxelder bugs is to use professional pest control services. Pest control experts will be able to remove these bugs from your home and keep them away in the future. 

There are a few things you can do to prevent boxelder bugs in your area:


Fill in cracks in your walls and windows both inside and outside. Replace damaged weather stripping. Look for damage and make repairs to your roof and rain gutters.


If you live in an area with a significant boxelder bug population, you may want to consider removing boxelder trees from your property—especially if they’re close to the perimeter of your home. You can also trim down branches that touch the outside of your home to decrease the chances of the insects finding their way indoors. 

Whether you’re seeing a sudden influx of red-and-black bugs inside your home or cluttering the facade of your house, boxelder bugs can be a considerable nuisance. Rather than risk exposure to foul odors, unsightly stains, or even the occasional bite, hire a professional to get rid of these insects. For any boxelder bug problems, contact Joshua’s Pest Control today.



Courtney Enzor has worked in the pest control industry for about a decade. From helping you build a fly trap to giving you the best tips for identifying various bugs, she loves answering all your pest-related questions and sharing her pest-related expertise through writing. At the end of the day, she hopes her content will help people avoid mishaps and keep families happy and healthy!