There are a group of bees, very important to the pollination of fruit trees and alfalfa and other crops, which are called “Leafcutter bees”.  Very occasionally, in the spring, you might by chance,  see a bee fly past as if on a magic carpet; if so, it  is a leafcutter bee, clasping a piece of leaf that it will take to its nest.  Leafcutter bees are solitary bees that nest in soft ground or wood or thick-stemmed plants (e.g., rose); or similar materials that the bees can excavate.  After excavating a tunnel, they line the tunnel with usually perfect circles of leaves that they cut from plants, prepare a nutritious “pollen loaf” within the leaf-lined tunnel, and lay an egg on top before sealing the tunnel and beginning anew, in order to produce more offspring. Interestingly enough, in Turkey and Iran, some leafcutter bees have been known to line their nests with flower petals, rather than leaves. For more information on the habits of these little pollinators, refer to Chapter 5 of the FAO publication Pollination Safety in Agriculture “Pesticide Exposure Routes for Wild Bees: The Leafcutter and Mason Bee Group – Megachilidae.”