Monthly Archives: July 2016

Minnesota Hygienic Queens and Varroa Control

I’ve been experimenting with different Integrated Pest Management approaches to controlling Varroa. I started using Oxalic Acid last year, and it’s pretty effective, but it has limitations.

Last month I tried creating an artificial brood break by caging the queen with a large push-in cage. The queens were supposed to stay confined for 12 days. The bees released them in 3 by removing the wax around the edges of the cage. So much for that idea.

Next I’m trying a strain of Italian bees that have been bred to be resistant. Minnesota Hygienics are not only supposed to be better at grooming and removing Varroa on bees in the hives (phoretic mites), they are also supposed to be able to detect when a Varroa is in a cell and removes the pupa infected.

I picked up three of these queens yesterday. I had already prepared the hives last week by removing the queens. This would give the hives a real brood break before the new queens were introduced. And I did a sugar roll to assess the mite levels before introducing the new queens so I can compare their effectiveness against Varroa.

However, when I opened the first hive, I found not only were there no emergency queen cells started, but there were eggs and tiny larvae present. I know I removed the queen, so how could there be eggs and larvae?

I got my magnifying glass to see if the eggs were centered and single. I really hoped I didn’t have a laying-worker hive in which a worker bee tries to lay eggs. No good could come from that. However, the eggs were centered in the cells and there was only one in each. So began the search for a laying queen.

Fortunately I found her pretty quickly and removed her. The hive will need at least a few hours to know she’s gone for sure, then I can introduce the new queen.

But the question remains: where did this queen come from? There’s been no evidence of supercedure, as I had recently checked that hive. I feel confident they didn’t start a queen before I removed their old one.

And they couldn’t have raised a new queen in the time since I removed their old queen. It’s only been 10 days. It takes 16-18 days for a queen to emerge and at least a week, usually longer, for her to mature and take her mating flights.

So, my best guess is a usurpation swarm. This is a small swarm of bees looking for a hive to invade. They sneak in a few at a time, kill the queen, and usher in their own. If one of these swarms happened by and discovered the hive was already queenless, that would be a bonus because they wouldn’t even have to remove an existing queen.

Whatever the case, I removed this mystery queen and will put in my new queen later today.

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Grafting Larva and Raising Queens

In May of this year, I attended a queen rearing workshop at the Texas A&M Honey Bee Lab, led by Dr. Juliana Rangel with Sue Cobey and Liz Walsh. Some of the workshop was above my beekeeping skills (like instrumentally inseminating a queen bee!), but much of it was very informative for my level. Sue Cobey confirmed my thoughts that seeding the local area with drones from my best hives will help spread good genetics throughout the area and combat the genetics we don’t want (like those unhappy Africanized bees). Have to be careful with that since lots of drones can lead to lots of Varroa, but that’s another story. You can see all of the photos from the workshop on my facebook page. For all the latest at my apiary, visit facebook.com/happyflorencebees. Like my page while you’re there.

In early June, I lost a new queen. She was there one week and gone the next. While I was disappointed at the loss (I had her shipped overnight from California, which costs a pretty penny), it did give me the opportunity to try my hand at grafting larva. In the past, when a hive needed a new queen, I would simply give them a frame of eggs and larva and let them do the rest. The results were usually good, but earlier this year I ended up with a drone-laying queen because the larva the hive used was too old. Grafting ensures the larva is the right age to develop into a queen.

On June 6, I chose a frame of young larva from a hive with a queen raised by another hive last fall. This queen has performed well: overwintering, calm temperament, and honey production are all good. Plus, they’ve done well at managing the Varroa. My new queen would have both feral genetics from local hives as well as from the Bee Weaver line.

Hial built a rack to support the frame while I was working, and in addition to the grafting tools, I bought a set of head-mount magnifying lenses so I could see what I was doing. I can see eggs with the naked eye, but not the first instar larva after they hatch (bee trivia: every 24 hours the larva makes a 360-degree rotation in its cell and sheds its exoskeleton for the next day of this metamorphic phase, which lasts about 5 days).

I tried both the Chinese grafting tool and the German grafting tool. The Chinese tool has a plastic tip, but it also has a little bamboo pusher that gently pushes the larva off the tip and into the cup. The German tool is all metal. After I got the hang of using the Chinese tool, I liked it better than the German tool, but the German tool was perfect for cutting the wax cell from around the larva.

I practiced lifting slightly larger larva first, so I could get the feel for using the tools. In doing so, I discovered cutting away the wax cell made lifting easier. I fumbled plenty, either scraping them up the side of the cell, not getting enough royal jelly, or just plain squishing them. But after a bit, I finally got the flow of lifting, scooping, and transferring the delicate larva. Fortunately, I had a work space in my new honey house where I could work with plenty of light.

I only needed one queen, but grafted 10 larva, knowing that most wouldn’t make it.

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Delicate work. It looks dark in the photo, but there was really lots of light.

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Wrapped and ready to install

I kept them covered with a damp paper towel to prevent them from desiccating. After grafting ten larvae and getting the bar into the frame, I wrapped it all with a damp towel and headed out to the queenless hive. This fit in with Lawrence Conner’s preferred queen rearing set-up, in which a well-populated but queenless hive is both cell builder and cell finisher. That prevented having to shake nurse bees from a donor hive to get the cells started and then transferring the started cells to another hive after a couple of days to finish the cells. My queenless hive was able to do both. If you want to learn more about Connor’s work, read his book, “Queen Rearing Essentials.”

I placed the frame of cells in the center of the hive and left it for several days. When I went back three days later, the bees had accepted three grafts and were building beautiful queen cells around them.

Rather than selecting which queen to keep or transferring cells to nucs, I left all the cells. The first queen to emerge would be the winner. I waited patiently until June 27 to start looking for eggs. There weren’t any yet. Waited some more…

I almost gave up, since a virgin queen should be able to take her first mating flight about 5 days after emerging from her cell and it had been longer than that already. But while I waited, I read on other beekeeping sites about the queen rearing calendar and tried to be patient.

Then on July 4, I saw what I was hoping for! Eggs and tiny larva. I had successfully raised a queen from grafted larva! I marked her a few days later.

graft queen

If all goes well with this queen and she has calm brood with good Varroa resistance, I may raise more queens next year from her rather than buying from an apiary.

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