There are lots of good books and web pages that contain blueprints and detailed information on the construction and deployment nest materials for leafcutting and mason bees referred to as: nest boxes, bee blocks, bee houses, or trap nests. The easiest attempt to provide nesting materials to mason and leafcutting bees is to drill holes (see below for hole sizes) in dead standing trees that are exposed to a limited amount of sunlight during the day. Nest materials can also be made simply by bundling drinking straws or bamboo stems together. More sophisticated nest materials can be made by drilling holes in blocks of kiln-dried wood, 8 to 20 holes / block at a spacing of at least 0.5 to 1.0 inch apart. In all cases the hole diameter should range from 3/16 inch to 5/8 inch diameter. On average a 5/16 inch diameter hole is suitable for most species of leafcutting bee. Specific choice and use of various hole diameters depends upon the species complex that occur in the area. A good first step is to deploy several diameters and over time learn which sizes are preferred. Straws or holes should be at least 6 inches long, longer holes or straws are preferred. Slippery straws are usually rejected. Thus coated paper straws tend to be more readily accepted than plastic straws. One can coat the inside of slippery straws with carbon dust or other fine dust that provides the adult females traction. Kiln dried or old dry wood is important for the manufacture of blocks since wet or green wood will extract the moisture from the bee tunnels sometimes dehydrating the larvae and pollen food ball. Some enthusiasts coat the inside of the tunnels with paraffin or polyurethane, or place straws inside the drilled holes. Nest materials can also be purchased from several vendors. Do not despair if they are not occupied during the first couple of years. Sometimes it takes a while before leafcutting or mason bees move into a habitat looking for nest sites, especially habitats that were previously devoid of nesting sites. Several other arthropods will colonize these nest materials, various species of spiders, ants, and Eumenid wasps, a solitary yellow jacket that collects and stores caterpillars and beetle larvae in the tunnels to rear their young. Similar to mason bees, these gentle wasps cap the tunnels with mud. Deployment of the nest materials in your yard or farm is discussed at FAQ 40608.
- Frank Drummond, University of Maine
