SMR/REC protocol

[B+.]

The SMR/REC protocol is described here for anyone who would like to test for this trait

 

[Cuttingedge]

Thanks for posting this.

 

[B+.]

Thanks for posting this.

You might want to read the Harris, Danka & Villa paper that talks about RECapping too.

 

[Repwoc]

Why does VD not suffer from the effects of intensive in-breeding? It seems that every mite is the result of sister-brother mating.

 

[B+.]

Why does VD not suffer from the effects of intensive in-breeding? It seems that every mite is the result of sister-brother mating.

In bee breeding, we think of inbreeding as being a damaging problem that we should avoid. However, not every species suffers inbreeding to the extent that honeybees do. It comes down to the amount of genetic diversity within the species. About 5% of the varroa destructor mites will be infertile and never reproduce.
I would happily bow to someone with superior knowledge on this topic if someone else wants to explain it.

 

[mbc]

Why does VD not suffer from the effects of intensive in-breeding? It seems that every mite is the result of sister-brother mating.

More than one foundress mite can be in the same cell so not necessarily sister/brother mating.

 

[B+.]

More than one foundress mite can be in the same cell so not necessarily sister/brother mating.

This is true, but, I think the question related to inbreeding within a single varroa family. It is quite normal for a single foundress to reproduce in a cell. I see it all of the time but I'm not aware of any studies that look at the inbreeding depression in these circumstances.

 

[Repwoc]

This is true, but, I think the question related to inbreeding within a single varroa family. It is quite normal for a single foundress to reproduce in a cell. I see it all of the time but I'm not aware of any studies that look at the inbreeding depression in these circumstances.

Well, I wondered why VD doesn't seem to be affected by inbreeding. If there's a mechanism for introducing genetic diversity then that may be the reason.

More than one foundress mite can be in the same cell so not necessarily sister/brother mating.

OK - suppose that 10% of cells are infected, is it reasonable to assume that 10% of the infected cells will be double-occupied? Is that sufficient to ensure genetic diversity?

Since VD is haploid/diploid, shouldn't the high inbreeding result in a high incidence of diploid males?

 

[B+.]

suppose that 10% of cells are infected, is it reasonable to assume that 10% of the infected cells will be double-occupied? Is that sufficient to ensure genetic diversity?

Since VD is haploid/diploid, shouldn't the high inbreeding result in a high incidence of diploid males?

Not really. When I do VSH examinations, I will only find a few that have more than one foundress.
I think varroa is not as susceptible to inbreeding as you're suggesting.
It's as easy for you to look it up as it is for me though.

 

[SDM]

Why does VD not suffer from the effects of intensive in-breeding? It seems that every mite is the result of sister-brother mating.

It varies in hive throughout the season, whenever brood levels drop , inbreeding decreases, the ratio of fertile to infertile mites shifts in response to this inbreeding, so it's fair to say they are affected by it.
They outcross successfully though because of the tendency of mite infested bees to drift. Combine that with beekeeping tendency to keep multiple colonies close together and we have some of the reasons why VD is a bigger pest in honey bees than it was to it's original host.

 

[B+.]

It varies in hive throughout the season, whenever brood levels drop , inbreeding decreases, the ratio of fertile to infertile mites shifts in response to this inbreeding, so it's fair to say they are affected by it.
They outcross successfully though because of the tendency of mite infested bees to drift. Combine that with beekeeping tendency to keep multiple colonies close together and we have some of the reasons why VD is a bigger pest in honey bees than it was to it's original host.

You are addressing a different question which was off-topic anyway.
It has nothing at all to do with the way phoretic mites move between hives and everything to do with the mating habits within the cell [reproductive phase].
There is a pretty good write-up of general varroa life-cycle here .
i.e. how does a single son, mating with its sisters, not introduce inbreeding depression in its progeny?

 

[Repwoc]

Thanks for posting that link. It's an interesting article, but doesn't say anything about why VD is unaffected by inbreeding.

 

[SDM]

As i said, it is affected . They have higher numbers of infertile mites after periods of inbreeding.

 

[B+.]

As i said, it is affected . They have higher numbers of infertile mites after periods of inbreeding.

Do you have something to support this? I haven't been able to find any papers on it and it doesn't correspond with my experience.

 

[SDM]

Do you have something to support this? I haven't been able to find any papers on it and it doesn't correspond with my experience.

Ive just been looking for it. The suggestion was that the variation in single mite infestation rates was linked to male mite mortality rates. So not exactly infertile mites, but mites who's offspring fail to mate.
I'll keep looking .

 

[B+.]

Ive just been looking for it. The suggestion was that the variation in single mite infestation rates was linked to male mite mortality rates. So not exactly infertile mites, but mites who's offspring fail to mate.
I'll keep looking .

I think you're on the wrong track but, by all means, continue looking.
Males don't survive outside the cell. Nor do juvenile females. Who suggested single foundress infestation was due to infertility? I don't see that at all. Single foundress infestations are common but their daughters fertility is not in question. It is only a matter of whether they are mature when the cell is opened (either by the bees emergence or hygienic behaviour in the other bees).

The question Repwoc posed was: Why do Varroa destructor not suffer the effects of inbreeding?. It's quite a leap of faith to say they do and to suggest single foundress infestation as the cause (without evidence).

 

[SDM]

Nobody said single foundries infestation was due to infertility. It's a consequence of the population cycles.
What was suggested is that those single clone mating cause a higher percentage of "premature" male mite mortality, I did say it wasn't a fertility issue.

 

[B+.]

Nobody said single foundries infestation was due to infertility. It's a consequence of the population cycles.
What was suggested is that those single clone mating cause a higher percentage of "premature" male mite mortality, I did say it wasn't a fertility issue.

I don't know where you get this from. There is no "premature" male mite mortality. Males and protonymphs don't survive outside the cell. Only mature females do. That is the way their life cycle works

 

[SDM]

I don't know where you get this from. There is no "premature" male mite mortality. Males and protonymphs don't survive outside the cell. Only mature females do. That is the way their life cycle works

I know how their life cycle works.
https://page-one.springer.com/pdf/preview/10.1023/A:1018492231639

 

[B+.]

I know how their life cycle works.
https://page-one.springer.com/pdf/preview/10.1023/A:1018492231639

You are quoting a 1997 paper that describes a method but gives no results and draws no conclusions. IMHO, it is poorly written piece of wishful thinking. It even quotes varroa as being jacobsonii (instead of destructor). It hints at a mechanism for varroa control but more recent papers refer to it as SMR (Suppressed Mite Reproduction) or VSH (Varroa Sensitive Hygiene).The reference to "possible role of premature male mite death" is also in africanized bees. You could learn more about the life cycle of varroa from a simple google search or reading Wikipedia.
The point I would make is; you need to inspect and record your findings or you don't know what is going on in your hives. You can't assume it is due to "premature death of the male mite". If you assume the wrong cause, any treatment you decide to administer may also be wrong.