#woolcarder bees

Above: Anthidium manicatum, commonly known as the European woolcarder bee

Woolcarder bees build their nests in existing cavities, often finding a hole or crevice in a tree trunk, log, plant stem, or manmade structure and then lining it with plant fibers. These soft, cottony fibers are also used to form a series of brood cells.

The fibers are known as trichomes, and they're collected from the leaves and stems of many different plants, including lamb’s ear, globe thistle, mullein, and rose campion.

Above: European woolcarder bees collecting fibers

Woolcarders are solitary bees, which means that they don't form colonies or live together in hives. Each female builds her own nest, and each male aggressively controls and defends his own territory.

Above: Anthidium florentinum, commonly known as the florentine woolcarder bee, constructing its nest in an empty keyhole

As this page explains:

The female uses her toothed mandibles to scrape trichomes off of 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.

Above: Anthidium manicatum

Female woolcarder bees will sometimes sting when their nests are threatened, but they're typically quite docile. The males, however, are notoriously aggressive -- they lack the ability to sting, but they will often chase, head-butt, wrestle, and/or decapitate any other insect that invades their territory. Some males have been known to defend their territory from intruders up to 70 times per hour.

The males are able to attack and fight other insects using a row of spikes located on the last segment of their abdomen. The central spike is the largest, and it's often used to decapitate other insects, because it has a wide, flat shape with a serrated edge, which allows it to function like a tiny bottle-opener; the woolcarder bee can simply slide that spike into the gap that separates the other insect's head from its thorax and then pry the head clean off. Woolcarder bees also have strong, sharp mandibles that can crush other bees.

There are many different types of woolcarder bee, but the most prolific is Anthidium manicatum, commonly known as the European woolcarder. Anthidium manicatum is a native species in many parts of Europe, Asia, and North Africa, but it has also become an established (and invasive) species throughout most of North America, South America, and New Zealand. It's the most widely distributed unmanaged bee in the world.

Above: a reticulated small-woolcarder, Pseudoanthidium reticulatum, and punctate woolcarder, Anthidium punctatum

Sources & More Info:

University of Florida: The Woolcarder Bee

University of Florida: European Woolcarder Bee, Anthidium manicatum

Oregon State University: European Woolcarder Bees

Bohart Museum of Entomology: Facts about the Woolcarder Bee (PDF)

Bumblebee Conservation Trust: Anthidium manicatum

World's Best Gardening Blog: European Woolcarder Bees: Likeable Bullies