Our guest speaker for the March 17th meeting was Dr. Mike Simone-Finstrom. Mike is currently at NCSU by way of the University of Minnesota and has been conducting new research projects on propolis. Mike explained and illustrated for the group why honeybees collect resins (complex plant secretions with antimicrobial properties) and incorporate them into the nest architecture.
Excerpt From Talk
Bees collect propolis on their hind legs and deposit it in the nest as a form of cement to seal cracks and to line the nest entrance and cavity. This is seen primarily in feral hives and is witnessed less in the managed Langstroth hives commonly used today. Although helping to increase the presence of resin in today’s managed hive bodies could have a positive impact in reducing the stress that bees are exposed to resulting in increased colony health. This can be done by ‘roughing’ up the insides of the hive body triggering the bees to fill the ‘non-bee space’ with propolis.
Mike’s research has shown that honeybees’ use of propolis may be a unique example of self-medication, since resin collection increases after they are challenged with a fungal parasite (some pests too). In petri dish experimentation Varroa treated with propolis were killed or slowed down, it was shown to kill the fungus that causes Chalkbrood and it has been seen as a prevention for American Foul Brood. Propolis controls and lessens the presence of bacteria which lets the bees immune system relax. If they have to focus on keeping their immune system on high alert this keeps their system taxed and at greater risk for disease. Under these conditions their wax and honey production is compromised.
- There are 70-150 chemical compounds in a single resin source
- Poplar trees are a main source, but leaves can be a source too
- Propolis is related only to the honeybee
- Valued as a medicine for humans due to its antimicrobial properties
- Resin collected by a forager bee must be removed by another bee in the hive
- Less than 10% of the foragers collect resin
It was a great talk that spurred some good discussion about the role propolis may play in our hive management as it relates to the prevention and treatment of various diseases and pests.