Most bed frames and box springs are made of wood, so yes, termites could use that for a meal. Realistically, however, subterranean termites will more likely feed on the interior walls, framing, and cabinetry so that they will come into contact first before an interior object like a bed frame. In the case of drywood termites, however, any piece of furniture can be at risk as a result because the drywood termite does not need contact with the ground for moisture.