Nesting and overwintering habitats
By Xerces Society for Invertebrate Conservation
While flowering plants provide pollinators with food, insects also require suitable shelter for nesting and overwintering. Most Bees and wasps create small nests beneath the soil or within dead plant stems or cavities in the wood. Other beneficial insects such as butterflies, wasps, moths, fireflies, lady beetles and ground beetles seek shelter in places that offer protection from predators and the elements, such as leaf litter and brush piles.
The primary habitat features used by pollinators and other insects for shelter include stems and branches of trees, shrubs, and wildflowers, leaf litter, undisturbed ground, bare ground, dead wood, brush piles and rock piles. Retaining and incorporating as many of these features as possible into your landscape (rather than "cleaning" them away) will help attract and support a diversity of bees and other beneficial insects.
Click on the preview below to open this useful resource on nesting and overwintering habitats for pollinators and other beneficial insects by Xerces Society for Invertebrate Conservation.