The flower petal nests of Osmia avosetta bees are durable and humid because of their multi-layer design, with a hard layer sandwiched between organic layers.


"With a flair for the colorful, O. avosetta makes a 'petal sandwich' out of two layers [of] flower petals inside a small burrow it digs in the ground, cementing them together with clay or mud. Then it caps the chamber with a mud plug, which seals the humidity inside while letting the outside harden. It's the perfect environment for the egg, said Jerome Rozen, curator in the Division of Invertebrate Zoology at the American Museum of Natural History." (Shipley 2010)

Bees build gorgeous underground flower-petal nests

Journal article
Nests, petal usage, floral preferences, and immatures of Osmia (Ozbekosmia) avosetta (Megachilidae: Megachilinae: Osmiini), including biological comparisons with other osmiine bees

Mason BeesOsmiaGenus