Box Elder Bugs

Walking through a community garden at dusk, when colors fade to gray, something orange caught my eye. Box elder bugs huddled on the pods, leaves and stems of a milkweed plant. I looked at the variations between young and mature bugs, all clad in orange and black. Further on, another milkweed plant acted as a second box elder bug condominium. Why only the milkweed plants? In the morning, I checked on the bugs. It was still chilly and they had not yet roused themselves for the day. I've been told that they like to come into people's homes in large numbers. Perhaps we need more milkweed condos.