The Mighty Pollinator: Leafcutter Bees

August 14th, 2019

Have you seen small, half-moon shaped holes taken out of the leaves in your garden? This may be a sign of leafcutter bees. They use the pieces of leaves to build nests. Leafcutter bees are great at pollinating, so it is best to leave them alone and allow them to exist peacefully in your garden.

The leafcutter bee is native to the western United States and are frequently used to pollinate alfalfa. It is also great at pollinating gardens and flowers. The bees carry pollen with their hair and much of it falls off as they move from flower to flower. This leads to great pollination within the garden. Comparatively, the honeybee wets the pollen so that it sticks to their legs, meaning much less pollen falls off. The leafcutter bee and honeybee are similar in size but differ in other ways.

Leafcutter bees are solitary bees, meaning they do not form colonies. The females will each find their own nest and line it with pieces of the leaves that they collect. Then she will be busy gathering pollen, laying eggs, and cutting holes for her nest. Other leafcutter bees will respect her nesting hole and will not lay eggs there while she is out.

Soft, rotted wood is perfect for a leafcutter nest. The bee will build tunnels through it or thick-stemmed plants and line it with pieces of leaves. They also use the leaves to make individual cells, where the females will lay an egg and then seal it with leaf pieces. The eggs will grow and develop within the cell and a young bee will emerge the next season.

Leafcutter bees only use rotting wood and do not cause damage to homes. Gardeners sometimes fear that the bees are damaging the leaves or rose canes by burrowing in them, but leafcutter bees rarely cause damage. In fact, some people enjoy raising leafcutter bees for the valuable pollination they provide to gardens.

One of our customers, Kirk, has found leafcutter bee nests in his garden! Have you seen any of their nests around? We’d love to see your photos!