For the Willamette Valley- check with your extension office for dates in your area.
SUMMER BEE - Leaf Cutter Bee
Mid-May to June First
Put your leaf cutter blocks in your bee house- after you take in your tubes/blocks for the Blue Orchard Mason Bee. The leaf cutter block has 1/4” holes with thin sheets of wood between the layers. Tape the back onto the leaf cutter bee block and place the block inside the bee house to give the bee a dark hole.
OR...In mid May you can put your block on top of the nesting house for an earlier start.
Note: Do not shove the block to the back of the bee house. The front edge should be about 2” inside the bee house.
June to October
Leaf cutter bees are active. Evidence is a semi-circle cut out of a leaf (especially on smooth leaves like rose, lilac and serviceberries.)
Put blocks in a paper bag with the top folded over and stapled shut. Put the block in an unheated garage or shed for the winter. Leave it there until late spring. “Bee Notes” will give details on getting the bees ready for summer
October - May
They are at the pre-pupa and pupa stage during this time. The pupa inside the cell will develop into an adult leaf cutter bee.
Stay tuned for more information on Bee Notes and at the next BEEvent Pollinator Conference.
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Leaf Cutter Bees
Leafcutter bees are a solitary bee species, meaning they do not produce colonies like social insects (honeybees, wasps, ants) and do not store honey; however they are a very efficient pollinator. They are approximately the size of a honeybee but are somewhat darker in color and have lighter bands on their abdomen. Leafcutter bees are not aggressive and will not sting or bite unless they are being handled. In the wild, leafcutter bees nest in soft, rotted wood or in the stems of large pithy plants and use cut leaf fragments to form nest cells, which is where their name comes from. In commercial agriculture leafcutter bees nest in supplied wood or Styrofoam boards with pre-drilled holes. During pollination leafcutter bees are stored in large wooden houses or trailers. Leafcutter bees are more efficient pollinators than honey bees in alfalfa seed fields because the honey bee is worried about being struck in the head when they trip the reproductive structure of the alfalfa flower; this is not a problem for the leafcutter bee.
Both Megachile and the genus Osmia belong to the family Megachilidae, meaning “large jaw,” referring to their large mandibles. Megachile is non-metallic and dark bodied, often with abdominal hair bands. They are called leafcutter bees because they cut small pieces of leaves and flowers to line their nest cells. One non-native species, Megachile rotundata, is managed commercially in Oregon for the pollination of alfalfa. There are approximately forty species in Oregon.
These posts are from Master Gardeners, as well as speakers we have had at various events concerning pollinators. Subscribe to BeeNotes to get this information delivered right to your inbox!