More on Leaf-cutter bees!

Happy Wednesday everyone! I am pleased to announce that spring has begun in Denver, CO, and I am loving seeing all of the wonderful wildlife out and about! I was excited to see a big bumble bee bustling around my backyard yesterday!

Leaf-cutter bees are part of the same family as mason bees, and share the solitary lifestyle, but nest gregariously, next to each other.  In the spring leaf-cutter bees emerge from their leafy cocoons. Males emerge first and wait for the females to emerge. Males are waiting to mate, and will die in 3-4 weeks after emerging.  Females will live up to 8 weeks working to build a nest full of cells. She will lay between 35-40 eggs in her short lifespan!

Once a female has mated, she will search for an appropriate nesting site, preferably a hollowed out tube which lays horizontally.  She can excavate, unlike the mason bee, so a leaf-cutter bee might find rotting wood or thick stemmed plants to clear out and begin building cells. She has strong cutting mandibles (jaws), so the task of excavation is easy for her, but not fierce enough to damage property, like homes.

Now that she has cleared a nesting site, she begins collecting leaf fragments. She prefers rose plants, lilacs, green ash, and Virginia creepers for her leaves, but she will also use flower pedals. She cuts small round pieces, then large oval pieces, followed by small oval pieces to form the leafy cell. It takes her roughly 2 hours to complete this task.  She will use anywhere from 9-14 leaf pieces for each cell, depending on the size, in diameter, of her nesting site.  The glue-like substance in her glands as she chews adheres the pieces of leaves together.

Now that the leafy cell is composed, she begins collecting provision for her egg.  She loves clover and alfalfa for nectar, so these bees are popular amongst farmers, and I even plan to plant clover in my backyard this year! Her method of retrieving pollen is much like her cousin the mason bee. She dives into flowers and collects as much pollen on her abdomen as possible. She too, is a very good pollinator, and also better than the honey bee. One leaf-cutter bee can do the job of 20 honey bees!

The provision is layered as such: first pollen, then a mix with most pollen some nectar, then most nectar some pollen, and finally all nectar. This layering is in accordance with what the larva will need at various stages of its development.

She lays the egg on top of the completed provision and then seals the cell with another piece of leaf.  

To view what the inside of a cell looks like, click on the link below.

This is one day of work. One cell, one day, eight hours.  Then it begins again the next day until she has laid all of her eggs. She is a fierce and dedicated worker with many benefits to offer us too!