Chalk brood genetics question

[BigAshW]

Have identified a line of queen's we have that are a bit chalky so will be sorting those out next year. This led me to wondering about the genetics of it.

Do we know if the susceptibility for chalk brood is solely passed down along the queen line or are there chalky drones out there that will turn daughters of a resistant queen chalky?

 

[masterBK]

I think you will find that the genes for susceptibility can come down both paternal and maternal lines. I think, if my memory serves me well, there are several gene loci involved so the genetics gets a bit complicated.

If you have some existing knowledge about such things then have a look at the following
"
https://link.springer.com/article/10.1007/s13592-019-00702-y

 

[charlievictorbravo]

I think you will find that the genes for susceptibility can come down both paternal and maternal lines. I think, if my memory serves me well, there are several gene loci involved so the genetics gets a bit complicated.

If you have some existing knowledge about such things then have a look at the following
"
https://link.springer.com/article/10.1007/s13592-019-00702-y

I don't have the background to understand most of that paper but for me, the takeaways were:

1. In insects, antimicrobial peptides (AMPs), which are synthesized in the fat body and then secreted into the hemolymph, are effector molecules against pathogenic microorganisms (Lourenço et al. 2018).
2. ... applying AMPs might be a promising therapeutic strategy to control chalkbrood and the severe antimicrobial resistance.

If these peptides are synthesized in the fat body of bees, but the bees are under pressure from high numbers of Varroa mites, which eat their Fat Bodies in both the larval and adult stages, a chalkbrood issue could be an indicator of a Varroa problem too.

Is anybody aware of any artificially synthesized AMPs, particularly AMP defensin 1, that are available to beekeepers anywhere in the world as a chalkbrood treatment?

I suspect that one of the conclusions of this paper should have been that more research was needed in the use of AMPs as a treatment for chalkbrood.

CVB

 

[Ian123]

Even if you could treat CB isn’t it just likely to come back in those queens with susceptibility. Better to squish and find some that aren’t!

 

[BigAshW]

Even if you could treat CB isn’t it just likely to come back in those queens with susceptibility. Better to squish and find some that aren’t!

This was kind of why I was asking the question. If drones are also carriers of the gene then, if you're in an area with lots of chalky drones then there's a good chance that if you raise your own queen's they will end up susceptible?

 

[Ian123]

Yes agreed, I raise most of my queens and to be honest haven’t seen any chalkbrood for years. Even in sites with heavy tree cover and prone to damp in comparison to others. But then my breeders come from decent suppliers. I certainly saw some years ago in more mongrel type bees, and in some Italian types I had at 1 point. I’d still suggest if you start with a queen that’s not prone to the issue your on the right track. Then it’s a case of thinning out those and having the extras to do it, just like any good characteristics you wish to see in your bees. Ian

 

[Apiarisnt]

To cite an example with an experimental sample size of only one:

I have had one colony that has been notably susceptible to CB for a year or three, floor covered in mummies every time I looked. They supeseded earlier this season, and the incidence of CB appears already to have diminished markedly. Could have been merely the weather, but...

 

[Mabee]

This is the daughter (being removed) of my last CB queen. First year the mother had signs in Spring but it improved as the season went on. This year, her second year, was all Spring through into Summer, split to a nuc and requeened with her daughter who seemed good at first but started finding this each inspection. She’s now gone and i’ve introduced a new Q so hopefully will fix the issue. It’s quite sad when she’s laying really well but half the brood ends up like this. Hive nice and dry and all new combs this year so that is not the issue. To much CB not fair on the colony IMO! Mother was a dark local mongrel.

 

[Patrick1]

Yes agreed, I raise most of my queens and to be honest haven’t seen any chalkbrood for years. Even in sites with heavy tree cover and prone to damp in comparison to others. But then my breeders come from decent suppliers. I certainly saw some years ago in more mongrel type bees, and in some Italian types I had at 1 point. I’d still suggest if you start with a queen that’s not prone to the issue your on the right track. Then it’s a case of thinning out those and having the extras to do it, just like any good characteristics you wish to see in your bees. Ian

Interesting you didn’t have CB in the hives in damp areas under trees, I have it in one hive that I thought was due to the moisture being heated in the ground and rising up through the OMF, I have always thought the queen is responsible for the starting of it but that the damp increases it.

 

[Ian123]

I have always thought the queen is responsible for the starting of it but that the damp increases it.

Yes 100% I think conditions play a part but probably only show up an existing weakness. Ian

 

[Murox]

The National bee unit say Chalkbrood is a fungal disease caused by Ascosphaera apis. So does a queen become infected and act as a carrier for the fungus ? Or is there a genetic predisposition/weakness in the larvae ? What are the 'mechanics' of the infection? the larvae only acquire the infection via ingestion of contaminated food, so spores must get everywhere and get moved around the hive by workers.

 

[Wilco]

Yes agreed, I raise most of my queens and to be honest haven’t seen any chalkbrood for years. Even in sites with heavy tree cover and prone to damp in comparison to others. But then my breeders come from decent suppliers. I certainly saw some years ago in more mongrel type bees, and in some Italian types I had at 1 point. I’d still suggest if you start with a queen that’s not prone to the issue your on the right track. Then it’s a case of thinning out those and having the extras to do it, just like any good characteristics you wish to see in your bees. Ian

Do you use HMs thymolated syrup at nosema dosages?

If yes, could this be linked to potentially also reducing other fungal infections over winter meaning lower incidence over the rest of the season?

 

[Ian123]

I’ve used thymol for a long time and well before HM’s mix I tried the emulsified version but found no better or worse results. I still found odd cases in mongrel types and swarms. As I make a habit of requeening it’s not lasted long.

 

[Anduril]

https://beekeepingforum.co.uk/threads/chalk-brood.38873/Something not to try and nothing on the market after 4 years.

 

[mbc]

The National bee unit say Chalkbrood is a fungal disease caused by Ascosphaera apis. So does a queen become infected and act as a carrier for the fungus ? Or is there a genetic predisposition/weakness in the larvae ? What are the 'mechanics' of the infection? the larvae only acquire the infection via ingestion of contaminated food, so spores must get everywhere and get moved around the hive by workers.

The causative organism is fairly endemic all over the place, in soils and whatnot not just in beehives.
The queen isn't infected but lays eggs which develop into larvae which are susceptible to the fungus.
In lines of bees with a little susceptibility (yes, I keep some) the disease tends not to show up when the queens ate young and vigorous but will show up in subsequent years.
It's bloody frustrating to try and breed out of a system where susceptibility only shows up occasionally with age.

 

[Michael Palmer]

This subject comes up time after time, and year after year. The suggestions are always the same. More ventilation. Move the hive into the sun. Treat the colony with thyme, bananas, or whatever. To me the issue is genetic. Requeening is suggested, and certainly is the answer...but not with any run of the mill stock. If the breeder queens used to raise the queens you use for requeening have been through a hygienic testing program, the bees will have no chalk. I did this 20+ years ago. In '98, I sent 400 colonies to Florida for the winter. Mistake. They came home with the worst chalkbrood infection I have ever seen. Absolutely stinky rotten with chalk. I requeened the chalky colonies with carni queens selected for high hygienic response. A month or so later, I could find no chalkbrood mummies. None! After that, my breeding stock came from colonies that showed no chalkbrood. This hygienic trait has followed through to this day. In 2021, we found 2 colonies showing chalkbrood....2 of more than 1000 nucleus and production colonies. Typical once hygienic breeding stock has been identified.

Now I wonder...are any queen breeders in the British Isles selecting hygienic stock using the liquid nitrogen method?

 

[Ian123]

Now I wonder...are any queen breeders in the British Isles selecting hygienic stock using the liquid nitrogen method?

I doubt if it’s more than a handful quite literally. We have very few proper queen breeders in the UK. There are more larger scale queen rearers and a good number would/are using hygienic stock, the majority would be using imported breeder queens though to some degree or another. We don’t really have comparable programs or groups compared the European beekeepers. Ian

 

[Murox]

I doubt if it’s more than a handful quite literally. We have very few proper queen breeders in the UK. There are more larger scale queen rearers and a good number would/are using hygienic stock, the majority would be using imported breeder queens though to some degree or another. We don’t really have comparable programs or groups compared the European beekeepers. Ian

Thats very sad really.

 

[Finman]

Now I wonder...are any queen breeders in the British Isles selecting hygienic stock using the liquid nitrogen method?

This chalk brood issue has been handled numerous times during 20 years.

Hygienic stocks are not a proper way to handle chalk brood. First you must have sick larvae, and then hygienic bees can clean dead larvae.
Then you have holes in the brood comb.

Better way is to get chalk brood immune stock, which does not become sick at all and it produces normal larvae and pupae.

You must get a new resistant genepool outside of your old genepool. No idea to start to select genes from your old stock.

 

[Finman]

How I selected immune queens?

My mating nucs were CB contaminated. Those queens, which has first sick larvae, I squeezed.

It took 4-5 years to get rid off chalk brood about 20 years ago.