Bombus affinis
Photo: Wikimedia Commons (CC) via https://en.wikipedia.org/wiki/Bombus_affinis
Overview
A detailed profile for this species is sourced from the IUCN Red List of Threatened Species as assessments become available.
The rusty patched bumble bee has experienced catastrophic population declines of over 87% since the late 1990s, primarily due to disease outbreaks caused by commercially-reared bumble bee pathogens that spread to wild populations. Habitat fragmentation and loss of native flowering plants have further reduced available foraging and nesting sites, while pesticide exposure weakens colonies and impairs reproductive success. Climate change compounds these pressures by altering bloom timing of key nectar sources and shifting suitable habitat ranges northward.
Habitat
The rusty patched bumble bee inhabits diverse open habitats including tallgrass prairies, oak savannas, woodland edges, and agricultural landscapes with abundant wildflowers. Queens require undisturbed soil or leaf litter for underground nest sites, while workers forage on native plants like wild bergamot, New England aster, and goldenrod throughout the growing season.
