Subject: Is this a Bombus affinis?
Location: Massachusetts USA
August 11, 2017 7:18 am
Is this bumblebee feeding on a milkweed plant in Massachusetts a Bombus affinis?
This does indeed look like a Rusty-Patched Bumble Bee, a species represented on BugGuide with sightings in the midwest, though BugGuide does state: “MN to IN, plus a few remaining sites on east coast, see map per Xerces Society. Formerly Upper Midwest and Eastern North America: Ontario to New Brunswick, south to North Carolina. Historically known from more than 25 states.” BugGuide also provides this sobering information: “Declines of this species were first noted by John S. Ascher at Ithaca, New York, ca. 2001 when populations that were conspicuous in the late 1990s could not be located. At this and many other localities across its historic range affinis is no longer detected, but it has been shown to persist locally in the midwest and in New England. Abrupt and severe declines of this and other bumble bee species in this subgenus were widely reported soon after development of the commercial bumble bee industry and detection of high rates of parasitism in managed colonies. U.S. Fish and Wildlife Service announced (Sept. 21, 2016) that it is proposing to list the rusty patched bumble bee as an endangered species under the Endangered Species Act.” According to the Xerces Society: “The rusty patched bumble bee is a species of bumble bee native to eastern North America. Its’ workers and males have a small rust-colored patch on the middle of their second abdominal segment. This bee was once commonly distributed throughout the east and upper Midwest of the United States, but has declined from an estimated 87% of its historic range in recent years. The rusty-patched bumble bee was once an excellent pollinator of wildflowers, cranberries, and other important crops, including plum, apple, alfalfa and onion seed. Responding to a petition filed by the Xerces Society in 2013 to list the rusty patched bumble bee as an endangered species under the US Endangered Species Act (ESA), the U.S. Fish and Wildlife Service (USFWS) finalized the ruling and gave the rusty patched bumble bee endangered status under the ESA in January of 2017.” If your identification and our confirmation are correct, you might want to report your significant Massachusetts sighting to the Bumble Bee Watch as recommended by the Xerces Society Citizen Science program.
Thank you very much Daniel!