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Bee Atlas 2016 bee blocks

The Minnesota Bee Atlas is excited to share the results from our 2016 bee blocks.  Citizen science volunteers observed 116 blocks across Minnesota from April to October, 2016 to see which of the six sizes of holes were being used for nests and what materials were being used.  Female solitary bees began building nests in the backs of the holes by laying an egg on a ball of pollen and sealing off the chamber before laying another egg.  The resulting larvae would typically overwinter before emerging from the nests as adults the following spring or summer but the blocks were instead returned to St. Paul campus and placed in cold storage to simulate a Minnesota winter.  As the blocks were warmed in the spring of 2017, adult bees, wasps, and other invertebrates emerged.  Each specimen was pinned, identified, and will be stored permanently in the University of Minnesota Insect Collection.

More than 2500 specimens were recorded, including 1218 bees and 1140 wasps.  Representing 8 genera and 20 species, the bees made up the largest group.  Solitary wasps were the next largest group, including some parasitic species.  Ants, beetles, spiders, and earwigs were also present in the blocks.

As with any first year research project, there were some interesting discoveries.  Using timely volunteer observations, the Bee Atlas discovered at least one species of bee that is multivoltine, meaning it has more than one generation in a summer.  Anthophora terminalis, the orange-tipped wood-digger bee was an unexpected find in a block near Afton.  Another unusual bee was Stelis coarctatus, a nest parasite that lays its eggs in nests of Heriades carinata.

To view the complete results, visit and click on "Results."  You can then search by a particular species or click on "Block Locations" to see the list of species at any one location.

The Bee Atlas would like to send a big thank you to the volunteers involved with this project.

Funding for this project was provided by the Minnesota Environment and Natural Resources
Trust Fund as recommended by the Legislative‐Citizen Commission on Minnesota Resources (LCCMR)

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