Karl Foord - Extension Educator, Horticulture
I was walking through the Horticulture Display Garden at the University of Minnesota St. Paul Campus. A bee landed on the ground and disappeared. I got my camera but couldn't find the hole it had disappeared into, so I waited. In a few minutes the bee returned with a bit of leaf rolled under its abdomen and again disappeared down the now somewhat visible hole.
This was no leisurely entrance and exit from the hole. The time from seeing the bee approach the hole to disappearance was less than one second. It took less time for the bee to show at the top of the hole and exit. The bee exited headfirst so it had had enough room in the hole to turn around.
The bees that nest in this way are aptly named Leafcutter bees and are in the genus Megachile (Photo 1).
They are identified by the hair on the bottom of their abdomen which traps pollen. They do not have a pollen basket like honeybees.
Photo 2 shows a leafcutter bee next to a honeybee to show the size difference.
I documented this event with a video:
Leaf-cutter bee building nest
The bee took between 45 and 60 seconds to leave the nest retrieve a leaf piece and return to the nest. Entry and exit events have been patched together and slowed down by 50%.
Sometimes even at half speed the bee moves too quickly to appreciate what is happening, so I made a collage of still photos of nest entry (Photo 3) and nest exit (Photo 4).
I also wanted to know where it was getting its nest material. I found that leaves of Long leafed Speedwell Veronica longifolia had the characteristic holes created by the leaf cutter (Photo 4). Note that not all the leaf cuts are the same; oval pieces are used to coat the sides of the nest, and circular pieces close up the nest cells.
Other leafcutter nest sites are created in gaps between stones or bark, hollow plant stems or other preexisting holes. These bees do no real harm to plants in collecting leaf material, and they are good pollinators. Keep an eye out for them in your garden. They are a treat to watch.