CONTENTS
- Resilience in the Face of Winter Losses
- Bee Rescues – getting people out of a ‘sticky’ situation
- Varroa resistance - It Comes From the Queen
Resilience in the Face of Winter Losses
Following on from the article on winter losses in the last edition of BIBBA Monthly, we have now created a video in which Roger Patterson explains his experience of winter losses in over 60 years of beekeeping. He talks about potential causes of losses, how we can try and mitigate against those factors, and crucially explains a simple method of colony increase that anyone can use to build a surplus of nucs ahead of next winter to cover any future losses. If they are still surplus next spring, they could be passed to other beekeepers who have suffered losses.
Bee Rescues – getting people out of a ‘sticky’ situation
Karl Colyer
Throughout the country, there are lots of bees living in buildings and trees. Most don’t create any issues but there are requests to remove them and rehouse them somewhere else.
In this example, the bees were in the bedroom wall. The homeowners weren’t too worried about them untilthey felt how warm the wall was. The decision was made to safely remove the bees.
Once the internal plasterboard was removed, the first chunk of comb was taken out. This is often the most challenging piece to remove as everything is so tightly packed in the cavity and firmly attached to multiple surfaces. The comb is dark so the there have been bees here for at least two winters. It’s not always the same colony that occupies a cavity – some die out and are replaced by new swarms in due course. When a colony lives in a cavity for several winters, the bees will have survived without treatments, inspections and feeding so they are largely or wholly free-living bees at this stage. The genetics are potentially very valuable as they haven’t succumbed to varroa. There is some evidence of uncapping and recapping with the brood slabs - a positive indication of Varroa resistance traits.
This picture shows a couple of queen cells close to being capped over. We were within a couple of days of a swarm happening. Sometimes, it’s easy to find the queen. More often, as the comb with the queen on is transferred, it can become noticeable that the hum in the swarm box quietens down fairly quickly afterwards. The queen cells are an unexpected bonus as it gives an insurance policy in case the queen was not found, injured or lost during the rescue.
Removing a colony takes patience and care. The idea is to transfer the brood, comb and bees to a suitable travel box, replicating the original sequencing and positioning of the combs as much as possible. In this picture, you can see the fifth lump of comb is about to be mounted and inserted into the box, filling it completely.
It’s worth noticing the sheet on the bedroom floor to try to stop dust and honey drips getting onto the carpet. I also put a sheet of plywood under the sheet to fully stop any stickiness underfoot after I’ve finished up.
An essential but sometimes overlooked part of the bee rescue process is the proofing of the original entrance hole(s). In this situation, the bees had been entering via a slipped tile and the subsequent gap was enough of an invitation for a full colony to enter a year or two ago.
Bee rescues from buildings should not be taken on lightly. It often involves working at heights, in confined spaces and there is always the risk of damage to the homeowner’s property. Specialist items such as a thermal imaging camera, battery operated tools and a low power vacuum cleaner are incredibly useful, as are dust sheets, bin bags and a spare nuc box or two.
For the more complex rescues, it may involve reinstating a part of a ceiling, removing and replacing chimney pots and removing/replacing brickwork to access wall cavities. Each rescue will present its own access, materials, removal and repair challenges.
So why do I do bee rescues? Firstly, there is a lot of support for saving the bees and people are prepared to pay a sensible amount to have them competently and safely removed from their home and rehomed in a hive, looked after by a supportive beekeeper.
Secondly, I do it to obtain the genetics. OK, there are plenty of new colonies and colonies that have perhaps overwintered for a single season. A small but significant percentage of rescues involve obtaining bees that have been in place for several years. These colonies pretty much always tend to be disease-free, managing Varroa easily to the point where it’s hard to find any Varroa (there will always be some there). An interesting observation, having done a few hundred rescues now, is that the established colonies tend to be dark in colour and gentle to handle. Make of that what you will. I rear queens from these colonies on a regular basis.
For those involved in bee improvement and breeding, a key question has always been:
Do bees learn Varroa-resistant behaviour from each other, or is it inherited?
Klaas de GelderThe researchers showed that Varroa resistance is passed on through the queen and her offspring and not by workers learning from each other.
This means:
Resistance is genetic, not taught
Requeening is sufficient to change colony behaviour
There is no need to transfer “experienced” workers
by the Scientific & Technical Working Group: Karl Colyer and Paul Verrier
A review of Martin et al. (2024), Apidologie “Resistance to Varroa destructor is mainly transmitted by the queen and not via worker learning”
How the study worked
The team carried out queen swap experiments in both Hawaii and England:
- Varroa resistant colonies were given mite-susceptible queens
- Mite-susceptible colonies were given Varroa resistant queens
They then tracked mite levels and behaviour over time.
What they found
1. Mite-susceptible queens led to colony failure
- Mite levels rose significantly
- Colonies eventually died
This happened even when the original workers had been from resistant stock. Resistant workers did not pass on their behaviour.
2. Varroa resistant queens produced resistant colonies
- Mite levels stayed low
- Colonies survived and reproduced
This occurred even when starting with susceptible workers. The queen’s offspring determined the outcome.
3. Hygienic behaviour follows the queen
Key traits such as detecting infested brood, uncapping/recapping cells and removing infested pupae were strong only in colonies headed by Varroa resistant queens.
Some mite-susceptible colonies showed partial responses (e.g. recapping), but failed to control mites effectively.
Implications for BIBBA breeding work
Queen selection is central
This paper reinforces a core BIBBA principle that Improvement depends on selecting and propagating the right queens. Worker origin matters far less than the genetics of the queen.
Requeening is an effective tool
To improve a colony, introduce a queen from resistant stock and allow her offspring to replace the existing bees. There is no need to transfer across the worker bees from resistant colonies.
Local breeding works
The study used locally mated queens, and resistance was maintained. This supports open-mating and, possibly, the importance of improving the local drone population
A practical BIBBA takeaway
For BIBBA members, the message is straightforward:
- Identify and breed from proven resistant colonies
- Use requeening to spread those traits
- Work collectively to improve local mating conditions
Conclusion
This study provides strong scientific backing for what many breeders have observed in practice; If you want Varroa-resistant bees, breed from the right queens. This places BIBBA’s long-standing focus on selection, breeding, and local improvement firmly on the right track
Feedback from the Scientific & Technical Team
- Although limited to two sites and a relatively small number of colonies, the clear take home message is that colonies headed by varroa naïve queens lose VR activity with a corresponding increase in the levels of varroa. Intriguingly, these colonies also suffered high losses over the course of the experiment – a development that could be consistent with exposure to increased viral pathogen loads.
- It’s worth noting that several varroa naïve queens swarmed during the course of the study with their colonies being taken over by a daughter which presumably mated with local, presumably VR, drones. Despite this input of paternal VR genetics, these colonies still appeared to be varroa sensitive – although the numbers were extremely small.
- Overall, this study shows that VR traits are genetically encoded and possibly maternally inherited. Suggesting that a locally mated VR queen used to re-queen any colony will ultimately cause this colony to itself become VR.
- Given the scale of commercial queen rearing, this suggests that VR traits, once taken up by commercial queen producers, could be rapidly disseminated. And may even represent an ‘added value’ trait to those queen rearers ready to make the leap…
- The inheritance of VR gene(s) seems likely, but it would be interesting to see what happens on the next generation(s) of presumably, open- mated queens. It would be useful to see how well the trait persists.
- It always seemed reasonable to me that the VR trait of brood uncapping might be genetic because (as the authors spotted), the Grindrod and Martin 2021 paper identified that there are two unique compounds (ketones and acetates are stated) that are present when there are varroa mite offspring present in the cell. This one could presume lead to the suspicion that the VR bees have developed the ability to recognise this new off-smell and consider it requires investigation. It is possible that the compounds found are often below the sensitivity of the workers sensilla and there may not be sufficient sensing for low levels. This is then open to an evolutionary mutation that leads to greater sensilla sensitivity to the particular compounds, or just another sensilla pack maybe. This may then lead to; once a VR queen, we have a chance of always a VR queen if the gene is not too recessive. The gene or genes responsible may of course not be the direct cause of a change, but maybe it initiates some other possible epigenetic change that gives rise to additional sensilla or modified sensilla production – the mechanism may be extremely complex.
- For the BIBBA member this paper bears really good news. Once you have a VR queen you could easily get more and repopulate your apiary with potentially VR queens.
- In the small apiary, there is the opportunity of just getting some VR queens from local breeders of local bees.
- There really is some long-term hope that this might at long last be a good solid reason to celebrate that our bees can live with varroa and see it off when it matters.
