Unusual nesting behavior in Megachile (Eutricharaea) rotundata (Hymenoptera: Megachilidae)

The Alfalfa Leafcutter Bee, Megachile (Eutricharaea) rotundata (Fabricius), is one of the most studied solitary bees in the world. Although its nesting biology is well documented, it has not yet been reported nesting in cavities that expose the nests to open environments. Reported here for the first time is evidence of this species nesting in an unusual manner which would subject the natal cells to exposure and increased parasite attack