Sorry to disappoint anybody here, but it turns out the specimen from
Beaver Island collected here in Michigan is really the tri-colored
bumble bee, B. ternarius, not B. affinis. A picture of the specimen
was sent to Sarina Jepson at Xerces by Nate Walton, the person who
collected it, after I hastily posted about it here and Sarina sent it
to Sheila Colla who confirmed the ID.
In other words, B. affinis has not been confirmed on Beaver Island.
Instead, it is Bombus ternarius that is apparently alive and well on
Julianna Tuell, Ph.D.
Department of Entomology
Michigan State University
202 CIPS Bldg.
East Lansing, MI 48824