About the Bee

Needs:

The rusty patched bumble bee needs three things: nesting habitat, floral resources to gather pollen and nectar, and overwintering habitat.

Nesting Habitat:

Rusty patched bumble bee nests are typically in abandoned rodent nests or other similar cavities, one to four feet below ground. Rusty-patched bumble bee nests have also been occasionally observed above ground. Nests are thought to be typically within 1 km (0.6 mi) of summer foraging areas. Nests locations are likely be in open areas or near open areas where it is not heavily forested and not too wet (i.e., not marsh, shrub wetlands, or wetland forest). Rusty patched bumble bee queens search for nesting sites after emerging in the spring and the nests are occupied by the colony throughout the active summer and fall flight period.

Overwintering sites:

Bumble bees overwinter in small chambers in loose soil and/or leaf litter just a few centimeters below the ground or they use compost or rodent hills/mounds. Little is known about the specific overwintering habitats of rusty patched bumble bee foundress queens (the queens that develop in late summer and are the only members of the colony that survive winter). Overwintering habitat is often in or near woodlands or woodland edges that contain spring blooming herbaceous plants, shrubs, and trees, which allows proximity to woodland spring blooming flowers, particularly spring ephemeral wildflowers, a critical early spring food source. Solitary queens mate in the fall and overwinter roughly from mid-October through mid-March.

Floral Resources:

Bumble bees gather pollen and nectar from the flowers of a wide variety of plants, typically within 1 km (0.6 mi) of nests. The nectar provides carbohydrates and the pollen provides protein. The species is one of the first bumble bees to emerge early in the spring and the last to go into hibernation. To meet its nutritional needs, therefore, the rusty patched bumble bee requires access to a diverse group of plant species to ensure that there are flowers in bloom throughout the colony’s long active flight period, roughly from mid-March through mid-October. The number of queens that a colony can produce is directly related to the amount of pollen that is available.

Spring Foraging Habitat:

Rusty patched bumble bees may depend on woodland spring ephemeral flowers because of the species’ early emergence; in the spring (roughly, mid-March through May) it is often found in and near woodland habitats.

Summer and Fall Foraging Habitat:

Bumble bees typically forage within 1 km (0.6 mi) of nests. While the rusty patched bumble bee may visit any available flowers within the typical foraging distance of its nest, it is reasonable to assume that core foraging areas are those areas with concentrated resources (e.g., open fields and prairies with large patches of blooming native flowers) where the bee can find pollen and nectar while minimizing energy expenditure.

Management Objectives and Targets for High Quality Rusty Patched Bumble Bee Habitat

Ideally, managed areas would have all three habitat features necessary to maintain one or more colonies of rusty patched bumble bee: nesting habitat, floral resources, and overwintering habitat. We recognize, however, that not every management area will contain all the features necessary for one or more colonies (e.g., small areas of land may only contain one key feature, such as overwintering habitat) and that areas are managed for a variety of purposes. We encourage land managers to consider how the areas under their management can contribute to habitat at the larger landscape level context in order to contribute to the conservation of one or more colonies of rusty patched bumble bee. For example, it is important to provide habitat heterogeneity at the county scale to help buffer from extreme events and climate variability at a broad scale.

Ideally, to sustain a colony or multiple colonies, an area would contain features and habitat characteristics necessary for foraging, nesting and overwintering that are identified in the following management objectives and targets.