Managing Boxelder Bugs
Black and orange bugs congregated on the sunny side of your house in fall are likely boxelder bugs. They are not harmful to plants and people, but certainly are annoying.
The immature bugs feed on ground level vegetation throughout the summer. The adults move to female boxelder trees, a type of maple, and occasionally to other maples and ash trees to eat and lay eggs. Their feeding does not harm the trees.
The problem usually occurs when the adults seek a warm sunny spot, usually the side of your home, to warm themselves in fall. As temperatures cool they often find their way indoors through cracks and crevices. Repair and fill any crevices to keep these insects out of the house. Manage high populations by vacuuming as they congregate or spray the side of your house with soapy water. Test the siding first to make sure the soapy solution will not change the color of your siding.
A bit more information: Removing the tree is not guaranteed to solve the problem. Adults can fly and may find their way to the sunny side of your home. Better to seal the house to keep them out or learn to live with these annoying pests.