Rusty-patched bumble bee
Bombus affinis
A generalist bumble bee of the eastern and upper-midwestern United States, named for the rust-colored patch on the abdomen of workers and males. Like other bumble bees it performs buzz pollination, grabbing a flower's anthers and vibrating its flight muscles to release pollen that other pollinators cannot reach. As a short-tongued generalist it forages a broad sequence of native perennials across the colony's spring-through-fall flight, with documented Midwestern records concentrated on genera including Monarda, Agastache, Pycnanthemum, Eutrochium, Veronicastrum, and Solidago. Colonies nest underground, typically in abandoned rodent burrows.
Conservation
The first bee listed as Endangered under the U.S. Endangered Species Act (USFWS, January 2017), and assessed as Critically Endangered on the IUCN Red List. The Xerces Society, which petitioned for federal listing, treats it as critically imperiled. Abundance fell by roughly 87-92% from the 1990s to the 2010s, and the species is now largely restricted to the upper Midwest and parts of the Appalachians. Providing a continuous, pesticide-free succession of native bloom plus undisturbed nesting and overwintering ground are the canonical garden-scale conservation actions.