Thursday, April 2, 2015
Bee Gardens Trump Bee Hotels: A New Canadian Study
A new study out of Toronto suggests that planting bee gardens is a better strategy than building bee hotels. The study by Laurence Packer and J. Scott MacIvor found that bee hotels fill up with about as many introduced bee species as native bees, but that wasps that predate bees outnumbered the other guests. The research took place over two years, so it will be interesting to see future studies to see if pest buildup increased over four years to a population "sink" or crash, which is a natural cycle.
The study suggests that it's very important where you put the hotel. The best place? In a bee garden. The highest percentage of native bees on the guest list were found in backyard gardens. Another important finding was that it is very important to locate the hotel in a sunny spot which will be less likely to be overcrowded with wasps. The conclusion to the study warns businesses who sell bee hotels not to "bee-wash" their products with claims that they boost native bee populations, when in fact more research needs to be done. In the meantime planting more flowers for our native bees is your best investment.
The sad little mason bee in the photograph above is from my back yard. She is covered with mites and was trying to groom them off. Males will mate with her and the mites will jump onto them. She will probably not live very long. These bees are nesting in the cedar shingles of our house. Speeking of bee-washing, if you do have been hotels, make sure you clean the cocoons in the fall to prevent bees being overloaded with mites and to help prevent the buildup of parasitic wasps. If you have a bee hotel you cannot clean, learn how to cycle out old materials to prevent this buildup of pests and research which hole sizes are best for native bees rather than introduced bees.
You can read the entire study called 'Bee Hotels' as Tools for Native Bee Conservation: A Premature Verdict? by Laurence Packer and J. Scott MacIvor in PLOS One.