While working with Kathi-Luise to get her bees ready for winter, we noticed that they chewed through the entrance reducer we added to make other entrances. This is a sign of chewing bees and since I was already thinking about it, when I was in my bees the next day I noticed that one of my hives had done the same thing.
This is a good thing!
I first learned about chewing bees at an NC Beekeepers conference in 2014. Dr. Greg Hunt from Purdue was one of the speakers and talked about bees that they are breeding at Purdue that are more aggressive with the varroa and not only pull them off of other bees, but bite off legs of the varroa before throwing them out of the hives. This is one way bees are learning to control mites in their hives. Also speaking at that conference was Judge Dan O’Hanlon from West Virginia. Judge O’Hanlon was a bee breeder (he’s now retired) and helped start the Heartland Honey Bee Breeders Cooperative (HHBBC). Members of the HHBBC were working with Purdue and took some of their virgin queens to be artificially inseminated with drones from the chewing bees being researched. (You can buy queens from the HHBBC with these traits here: https://hhbbc.org/).
I bought some queens from Judge O’Hanlon in 2015 and some of the queens were the chewing bees (aka leg biters). I left the small opening of the entrance reducer on their hive longer than they thought was necessary and the bees chewed it to make a bigger opening. They also tended to bite me before stinging me. And as part of a discussion on varroa mites for the Surry County Beekeepers Association, I collected some mites on a sticky board from this hive and we looked at them under a microscope and sure enough — they were missing legs.
According to Dr. Hunt and co-op member Jeff Berta, the chewing bees can be found in nature so you don’t necessarily need to buy a queen to have chewing behavior.
Both my bees and Kathi-Luise’s bees did great this year in dealing with the varroa. Mine didn’t need treated and we treated Kathi-Luise’s bees only once because the threshold got to 3 bees/100 bees and the new guideline is 2/100.
Here are some pictures of what the chewing looks like:
Interested in learning more? Here are two links with good information.