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Wednesday, July 6, 2011

Mason Bees Probably Not the Best Choice for Desert Pollination

Bee boxes made for leafcutter bees at The Orchard
Q. Do we have mason bees in las vegas? My yard is 50ft x 25ft. do you think it’s a good or bad idea having a mason bee house?

Circular holes cut on the leaf magin of a bottle tree leaf.
Leaf cutter bee house and bee entering hole
A. We don’t really have Mason bees or Orchard bees that I know of. We rely mostly on leafcutter bees as a wild source of bees for pollination. I have sat in the orchard for about one hour a few years ago during full bloom and counted bees visiting flowers on a peach trees. The leafcutters are smaller in size so they are easier to distinguish from Italian honey bees. We have ten hives of Italian honey bees in the orchard. My best estimate was that about 25% of our pollination on that tree was due to leafcutter bees.

I think you would waste your money in bringing some in. I think they might die in this climate. You can make your own leafcutter bee house by drilling holes in a 4x4 or 6x6 (better) or a tree stump with a 3/8 inch bit to a depth as deep as you can. Five inches is best but at least 3 inches. The female bees will lay their eggs in these long tunnels created with your drill bit. The State Entomologist in Nevada claims that the longer tunnels will favor the creation of more female bees since the eggs of males are laid the first three inches or so of the tunnel. The deeper the hole, the more eggs that turn into females will be laid. Shallow holes will still provide for the production of bees but male bees will be favored. As we all know, male bees are not as productive workers as females.

Basil damaged by leafcutter bee
You might keep in mind that leafcutter bees will make some damage to some leaves around your yard or garden but that's okay. They will grow back. Leafcutter bees favor leaves that are smooth and fairly delicate such as bougainvillea, roses, grapes, basil and the like. They take these leaves and use them to stuff the tunnels where they pack their eggs. The leaf stuffings provide protection for the eggs and food for them to eat as they emerge in a month or so.


  1. That's not basil they're eating.

  2. You are right! wrong picture posted and will correct it.

  3. Based on the expected life cycle of the mason bees to live anywhere from 6 to 8 weeks it would seem that the bees will have already laid their eggs and the adult bees already dead by the time the heat hits in July...so the bee condo could be brought indoors to continue pupating to avoid the heat.