In our November meeting, John mentioned that he has been concerned that we may be breeding resilience out of our bees. In particular he mentioned that breeding to reduce the amount of propolis that bees collect may be a mistake. One of the speakers at the 2014 Oregon State Beekeepers Association Annual Conference in Seaside was Dr. Marla Spivak at University of Minnesota who is doing research on that very topic.
Dr. Marla Spivak, Entomologist at the University of Minnesota
Dr. Spivak is a MacArthur Fellow and the McKnight Distinguished Professor in Entomology at the University of Minnesota who is studying the benefits of propolis to honey bees and the effects of agricultural landscapes and pesticides on honey bee and native bee health. She has a great TED talk called Why Bees are Disappearing. The following information is excerpted from her talk at the conference and from an article that is available from her lab: The Benefits of Propolis.
Propolis is plant resins that bees collect and deposit in the nest cavity. Feral bees coat the inside of their cavities with a rather thick layer of propolis. Propolis is hard for the bees to collect—they have to scrape the resin off the leaves, pack it on their hind legs, and then get help from other bees to pull it off of their legs. They must have a good reason for going to so much trouble.
Bees line their hives with propolis – the waxy, yellow substance seen here. Sci-Guru Science News
It turns out that propolis has very amazing health benefits to bees. One of Dr. Spivak’s graduate students found “… that bees exposed to a propolis envelope for just seven days had lower bacterial loads in and on their bodies, and had ‘quieter’ immune systems compared with bees in a colony with no propolis envelope. In other words, the propolis in the colony was killing off microbes in the nest, so that the bees’ immune systems did not have to gear up and make peptides and cellular responses that fight off infection.”
Dr. Spivak’s lab also found that the bees may be able to self-medicate. If you introduce chalkbrood into a hive, the bees will respond by increasing the amount of propolis in the hive by sending out more resin foragers.
How can beekeepers use this information? Dr. Spivak recommends that we should be encouraging our bees to gather propolis by using hive boxes that have rough surfaces on the inside. The bees will be more likely to create a propolis envelope on a rough surface. (I spoke to Stewart at Shastina Millworks, and he has supplied hive boxes with rough interiors for large orders recently. If there is interest in doing so for hobbyists, he will be glad to add them to his inventory.)
Dr. Spivak does not recommend painting the inside of hive boxes with a propolis extract—it is easier to let the bees deposit it right where it is needed. She also does not advocate feeding propolis, which is a powerful antibiotic, to bees. Bees do not eat propolis and feeding it to bees has not been shown effective against disease in the lab.
See also Bees ‘Self-Medicate’ When Infected With Some Pathogens and check out more research topics, and how to videos, at the University of Minnesota Bee Lab.