Wool-Carder Bees: these solitary bees harvest the soft, downy hairs that grow on certain plants, rolling them into bundles and then using the material to line their nests
Wool-carder bees build their nests in existing cavities, usually finding a hole/crevice in a tree, a plant stem, a piece of rotting wood, or a man-made structure, and then lining the cavity with woolly plant fibers, which are used to form a series of brood cells.
The fibers (known as trichomes) are collected from the leaves and stems of various plants, including lamb’s ear (Stachys byzantina), mulleins, globe thistle, rose campion, and other fuzzy plants.
From the University of Florida's Department of Entomology & Nematology:
The female uses her toothed mandibles to scrape trichomes off fuzzy plants and collects a ball of the material under her abdomen. She transports these soft plant fibers to her selected nest site and uses them to line a brood cell. Next, she collects and deposits a provision of pollen and nectar into the cell, enough pollen to feed a larva until it is ready to pupate. Lastly, she lays a single egg on top of the pollen and nectar supply before sealing the cell. ... She will repeat this process with adjoining cells until the cavity is full.
These are solitary bees, meaning that they do not form colonies or live together in hives. Each female builds her own nest, and the males do not have nests at all.
Female wool-carder bees will sometimes sting if their nest is threatened, but they are generally docile. The males are notoriously aggressive, however; they will often chase, head-butt, and/or wrestle any other insect that invades their territory, and they may defend their territory from intruders up to 70 times per hour. The males do not have stingers, but there are five tiny spikes located on the last segment of their abdomen, and they often use those spikes when fighting. They also have strong, sharp mandibles that can crush other bees.
There are many different types of wool-carder bee, but the most prolific is the European wool-carder (Anthidium manicatum), which is native to Europe, Asia, and North Africa, but has also become established as an invasive species throughout much of North America, most of South America, and New Zealand. It is the most widely distributed unmanaged bee in the world.
A few different species of wool-carder bee: the top row depicts the European wool-carder, A. manicatum (left) and the spotted wool-carder, Anthidium maculosum (right), while the bottom row depicts the reticulated small-woolcarder, Pseudoanthidium reticulatum, and Porter's wool-carder, Anthidium porterae
University of Florida: The Woolcarder Bee
Oregon State University: European Woolcarder Bees
Bohart Museum of Entomology: Facts about the Wool Carder Bee (PDF)
Bumblebee Conservation Trust: A. manicatum
World's Best Gardening Blog: European Wool Carder Bees - Likeable Bullies
Biological Invasions: Global Invasion by Anthidium manicatum
