Nest of Box Elder Bugs
Box elder bugs do not nest indoors year-round. Rather, they make their homes in box elder, maple and ash trees during warmer seasons and migrate into buildings and homes to find shelter for the winter. Adult bugs live and breed on the leaves of box elder trees, laying their eggs in spring. They feed on soft parts of box elder trees, including leaves, flowers and new twigs. They also extract juices, causing minimal to substantial damage to their host tree.
The eggs of box elder bugs are reddish brown in color, allowing them to stay well hidden in the bark of the host tree. After a few days, the eggs hatch into red and gray nymphs, which eventually mature and begin the breeding process again. Mature box elder bugs can be found gathering in large numbers on branches and boughs. Concentrations will be heaviest in areas receiving sufficient sunlight.
After summer, box elder bugs can migrate indoors, seeking shelter from the cold. They enter through small cracks and crevices within the building, and remain inside, hibernating, through fall and winter. They emerge when heat sources within the building are high and can be located in the warmest areas of a structure’s walls. While they do not cause damage to buildings, their droppings are unsightly and leave stains on furniture and linens.
To prevent box elder bug nests within your home, remove any box elder trees within close proximity and seal all cracks and crevices on the outside of the structure. These insects can also enter through windows and doors; ensure that these close properly and utilize screen doors to keep box elder bugs from entering.