Skip to Left navigation Skip to Main content Skip to Footer

University of Minnesota Extension

Species guide - species detail

Back to Species guide categories | Back to Bees

Stelis coarctatus (Cuckoo bee)



Stelis is a genus of parasitic bees in the family Megachilidae. They are nest parasites, meaning they do not make their own nests but lay their eggs in nests of other bees, usually in the family Megachilidae. Stelis sp. larvae kill the host larva and grow in its cell instead. Sometimes there are close pairings between host bee species and Stelis species. Other times the Stelis seem to be able to chose from several host bee species. Stelis coarctatus has been synonomized with S. vernalis (as noted in Gibbs et al 2017)


Stelis do not have scopa to carry pollen since they do not provision their own nests. Stelis coarctatus is a black or dark reddish bee with pale markings on the sides of the abdomen and very short pale hairs on its body. Their body form is fairly robust and cylindrical. They are a pretty small bee, roughly the size of Heriades.

Nest Structure

Stelis coarctatusparasitize the nests of Heriades carinata in Bee Atlas blocks. They have been recorded doing so in other places as well (Sheffield et al 2008, Mathews 1965)

Hole Sizes

Stelis coarctatus emerged from nests in column 3 (1/8 - 3/16") holes in Bee Atlas blocks.


No information at this time.

Activity Period

No information at this time.


Matthews, R.W. (1965) The biology of Heriades carinata Cresson (Hymenoptera, Megachilidae). Contributions of the American Entomological Institute, 1, 1–33. _________________________ _________________Gibbs, J, J.S. Ascher, M.G.Rightmyer, and R. Isaacs. 2017. The bees of Michigan (Hymenoptera: Apoidea:Anthophila), with notes on distribution, taxonomy, pollination and natural history._________________________ _________________Sheffield, C.S., Kevan, P.G., Westby, S.M. & Smith, R.F. (2008) Diversity of cavity-nesting bees (Hymenoptera: Apoidea) within apple orchards and wild habitats in the Annapolis Valley, Nova Scotia, Canada. The Canadian Entomologist, 140, 235–249.

Minnesota Record Map

These data are from the Minnesota Bee Atlas project.

Back to Bee species guide