April 2025 BIBBA Monthly-Original

What a difference a year makes - from last year's wash-out spring, we're now enjoying a spring that's brought out the best blossom for several years and the bees are enjoying every bit of it.  

In my varroa resistant apiaries, the bees are advanced, expanding their brood nests rapidly thanks to all the nectar and pollen coming in and they're also starting to fill supers. And I'm seeing lots of uncapping and chewing out, leaving exoskeletons on the insert boards. Daily average mite counts are a touch up from where they were in March, which isn't surprising given the big increase in the brood nest. But only a touch. My best hives are still showing a drop of fewer than one a day.  

Compare the 1st picture here which is from the insert board on one of my varroa resistant hives with the 2nd picture from a mite susceptible hive in an out-apiary. Guess which one I'll be re-queening this year? 

Picture1

Picture2

I was asked at a recent BIBBA meeting whether there were some good pictures of the sort of exoskeleton parts that show up on the insert boards. Here are a few pictures of some identifiable parts. Many parts aren't identifiable, but they all show a translucent pearly white colour. In the pictures below you can clearly see body exoskeleton parts with the segments visible, head parts with antennae as well as limbs.

April is the time to make final decisions about which colonies to breed or raise new stock from and which you want to re-queen, and it's no exception for the varroa resistant apiary. It's particularly important this year as it seems the swarm season is starting early and that provides a great opportunity to increase stocks by splitting and harvesting cells.

The colonies are also raising lots of drone brood, with some already hatched. I encourage drone production in my varroa resistant apiaries so I can flood the local area. They are taking good genetics with them. One method of encouraging drone production is to pop a super frame into your brood box and they'll build drone comb off the bottom of it.

Any breeding program will tell you to breed from your best and re-queen your worst, and certainly breeding from your best applies in my varroa resistant apiary.

If you've got just one varroa resistant colony, it's simple, multiply it using whichever method you use. Then when you have more stock, you can compare their mite drop data and levels of uncapping and chewing out and make decisions about which you continue breeding from in future years. This also provides you with a guarantee if for some reason the existing colony fails to raise a new queen after a split.

As part of the Westerham Beekeepers selection programme, I am lucky enough to have a few varroa resistant colonies and I want to continue to increase stocks this year and re-queen mite susceptible hives in other apiaries.

But which are the best colonies in a varroa resistant apiary? Varroa resistance is obviously the first trait that I select for. But is my best colony the one that does the most uncapping and chewing out? Or is it the one with the lowest mite count? Some colonies may be uncapping and chewing out more than the colony next door and yet its seasonal mite drop count is slightly higher than the neighbour.

Remember the equation you're looking for: Uncapping (as seen at inspections) and chewing out (as seen by pupal exoskeletons on the bottom board) will equal low seasonal mite colonies (measured by regular and consistent counts on the insert board).

For the sake of an example, if I have three varroa resistant colonies, two with an annual average mite drop  of three or four mites per day, and one with an annual average daily drop of seven a day, then I am not going increase from number three. I will probably increase from both the others and then continue monitoring and compare results from the resulting colonies, making the same selections next year and the year after and so on.

And what about re-queening your worst? While varroa resistant colonies are few and far between, I am not going to recommend re-queening when that queen could raise another new colony. Maybe you could come to an arrangement to pass it on to a local beekeeper? There are bound to be many who are ready to start their own varroa resistant journeys.

Varroa resistant summary for April:

• Even though there's a flow, you should still be seeing uncapping during inspections and pupal exoskeletons on the insert board as the brood nest expands.
• Keep doing a mite drop count at every weekly inspection. The daily average may have ticked higher since March, but not by much. If you start to see a continual increase in mite drops each week, you have a problem.
• Make a decision about which varroa resistant colonies you'll use to make increase or to re-queen other colonies. Choose the best based on mite count, and if too close to call then which is showing the best uncapping and chewing out.
• If you have only one colony, don't risk losing it, increase numbers if only to make certain you have a colony
• Swarm season provides a great opportunity to increase stocks by splitting and harvesting excess queen cells
• Encourage drone proliferation in your varroa resistant colonies to flood the area with your drones carrying the right genetics

Every month through the season, we will publish an article detailing what's going on in varroa resistant apiaries, explaining our observations, to help those who may be starting their varroa resistant journey.