Flower SandwichWhat appears to be part of a spring wedding bouquet is actually a nest for a rare species of solitary bee, a new study says.Called a "flower sandwich," the three-tiered arrangement consists of a thin layer of petals on the outside, then a layer of mud, and finally another layer of petals lining the inside of the chamber, according to study leader Jerome Rozen, a curator of invertebrate zoology at the American Museum of Natural History in New York.At the core of the sandwich is the bee's larva, which feasts on nectar and pollen deposited inside the chamber by its parent before the egg is laid and the nest is sealed. (Related: "Bees Like It Hot: Pollinators Prefer Warm Flowers, Study Reveals.")The colorful nesting behavior of the Osmia avosetta bees was discovered on the same day by teams in Turkey and Iran, where the insects are mostly found.

The teams jointly described the behavior in the February 2010 edition of the journal American Museum Novitates.—John Roach

Photograph courtesy J.G. Rozen, AMNH