New checklist features 270 species of native bees in Maine

The first checklist of bees in Maine, compiled using wild blueberry research records from the 1800s to present, as well as private and public collections, and citizen science observations, has documented a total of 278 species — all but eight of which are native, according to a scientific team led by University of Maine bee and pollination experts.

The new inventory of Maine bees is designed to serve as a baseline for measuring the effects of anticipated climate and habitat changes on native and exotic bee populations in coming decades, according to UMaine conservation biologist Alison Dibble, and entomologists Frank Drummond and Constance Stubbs, who led the research team.

The 278 bee species reflect 37 genera and six families. The largest genera are the sand bees, Andrena, and the sweat bees, Lasioglossum, each with more than 50 species.

The hope is that bees associated with other crops — including apple, highbush blueberry, cranberry, squashes and pumpkins — can be studied and added to the checklist, note the researchers — Dibble, Drummond, Stubbs, Michael Veit and John Ascher — who published their findings in the journal Northeastern Naturalist.

“Back in the 1990s, we were surprised when we reached 100 native bee species in our effort to develop this checklist,” Dibble says. “Now we have documented 270 native species for Maine. There are surely more to be found, and we know very little about the biology of most of these species, or whether they are in decline. Homeowners can help by not using pesticides, and by mowing less frequently so that flowers, which are bee food, are available through the entire growing season.”

A foundation for the inventory comes from decades of UMaine research of lowbush blueberry pollinators in the state. That includes three long-term studies of native bees in commercial wild blueberry barrens, published for the first time in the same issue of Northeastern Naturalist.

The earliest scientific studies of Maine bees include reports of entomological collecting trips beginning in 1861. Other sources of information for the checklist include taxonomic catalogs, and specimens in collections in the northeastern United States, such as the American Museum of Natural History, the Peabody Museum of Natural History, university collections at UMaine and Cornell University, and private collections.

Specimen identification by expert bee taxonomists was crucial to development of the checklist, as many obscure microscopic features had to be considered and new species are still being described. Ascher, a world bee expert formerly of the American Museum of Natural History in New York and now at the National University of Singapore, reviewed the majority of specimens, identified many of the more recent collections, and led the thorough literature search.

The researchers note that not enough is yet known regarding relative rarity of Maine bee species, but 21 species are considered unusual, including three first recorded in Maine as recently as 2016 (Epeoloides pilosulus, Melitta melittoides and Holcopasites calliopsidis).

The checklist is considered preliminary in that bee sampling efforts through the years have been higher in certain counties. While all of Maine’s 16 counties have bees on the checklist, five have more than 100 species: Hancock County (197 confirmed species), Penobscot County (181), Washington County (162), York County (104), and Lincoln County (102). Other counties require more research for additional bee species to found.

Contact: Alison Dibble, 207.359.4659,; Frank Drummond, 207.581.2989,