Insect pollinators can spend the winter in a variety of life stages (egg, larva, pupa, or adult) and this varies, depending on the species. Most native bees spend the winter in their nest cells as pupae, emerging as adults the following spring or summer, so it is critical to protect nesting areas from disturbance all year long, not just during the nesting season. One exception is bumble bees, which do not overwinter in their nests. Instead, new bumble bee queens emerge from their natal nest in the fall and search for overwintering sites, burrowing into leaf litter or loose soil. It is just as important to provide sheltered areas for them.
Butterflies and moths also overwinter in a variety of stages (egg, larva, pupa, adult). For example, Mourning Cloak butterflies overwinter as adults, while Eastern Tiger Swallowtails spend the winter as a chrysalis.
All need sheltered areas in which to spend the winter. To provide these safe havens, set aside undisturbed patches of habitat allowing leaf litter, standing dead twigs/stems, or other ground cover to remain. Do not till soil where there might be ground nests. “Wild,” unmanicured locations will provide the protected nooks and crannies that pollinators and other animals need for survival.