Box elder bugs feed principally by sucking juices from the box elder tree, but are sometimes found on other plants.
When box elder bugs build up to large populations and invade a home they are usually pests only by their presence,
although their piercing-sucking mouthparts can sometimes puncture skin, causing slight irritation.
They seek shelter in protected places such as houses and other buildings, cracks or crevices in walls, doors,
under windows and around foundations, particularly on south and west exposures.
Box elder bugs can come out even during the dead of winter when it is cold outside and the sun is shining.
They will then emerge in the spring to seek out host trees on which to feed and lay eggs.