Eastern boxelder bugs (Boisea trivittata, Rhopalidae) are usually only noticed by people in the fall, when the bugs seek shelter inside buildings. Throughout the summer these bugs feed on maple trees, especially boxelder (Acer negundo, Aceraceae). This tree has little commercial value, so these bugs aren’t considered pests.
These insects are hemimetabolous, meaning they don’t go through a complete metamorphosis in a pupa from a larval form to an adult form. Instead the immature instars resemble smaller, wingless adults, becoming larger and more adult-like with each molt. The nymphs live much like the adults, feeding on primarily boxelder trees. They ultimately molt into their adult form, and it is in this stage that they often seek winter shelter inside human habitations.
Boxelder bugs are harmless to humans. They aren’t considered pests and don’t bite. Although they can be unsightly as they gather to seek winter shelter, they will just as happily leave again in the spring. Like people, they just want a relatively warm place to survive the winter.