Mite Testing

[Bob Russell]

Some behind the scenes pics of private varroa research in New Zealand today.We may be ahead of the rest of the world by time but have got an extra day ahead by my date on this test.This hive running 55% infestation has held its own over the summer season.No treatment has been given as yet.

http://tinyurl.com/qzwxk

Comments and questions welcome.

[Jim Fischer]

> This hive running 55% infestation has held its
> own over the summer season.No treatment has been
> given as yet.

Its not unusual for a colony to survive with
no treatment for a summer, as the bulk of hives
left untreated (or treated using ineffective methods)
will die in the SECOND season.

[beemandan]

'will die in the SECOND season.'

Or, will collapse during the winter (even the first) when the smaller number of winter bees are infested by the same (or greater) number of mites and die from the added parasite pressure.

[George Fergusson]

That's amazing Bob. By all rights and purposes with an infestation rate of 55% that hive should already be dead. It's been estimated that a 14% infestation level will kill off a hive over winter. That they often live into the second season implies the colonies started out with a marginal mite population and it typically does take a couple of seasons for the mites to kill them off. I've got a few hives in that category. This ain't that category.

To what do you attribute your amazing success at breeding mites?

[Michael Bush]

>To what do you attribute your amazing success at breeding mites?

Thanks George. I was trying to figure out how to say that. [img]smile.gif[/img]

[George Fergusson]

>Thanks George. I was trying to figure out how to say that.

Hehehe..

According to Stephan Martin's paper on his varroa population model:

The model was used to test the prediction that any A. mellifera or A. cerana colonies of a given size have a maximum theoretical mite population (Martin, 1997a). The models’ predicted values for both A. mellifera (81000) and A. cerana (900) were in good agreement with the values predicted by Martin (1997a). 1997b). An A. mellifera colony will collapse long before these high levels are reached due to secondary viral infections."

Now, I don't know what percent level of infestation 81,000 mites in a hive corresponds to, but I'm guessing around 125% [img]smile.gif[/img]

Regardless... It still seems amazing to me that Bob's colony has a level of infestation of 55% and the colony is still alive.

[Michael Bush]

Varroa researchers are always desperate to get that many varroa to test with. [img]smile.gif[/img] Maybe you can sell the Varroa mites to researchers.

[Robert Brenchley]

Have you any idea what mechanism the bees are using to control the mites? I assume that this is what's happening, however they're doing it.

[Bob Russell]

>That's amazing Bob. By all rights and purposes with an infestation rate of 55% that hive should already be dead.

Correct if there were viral infections present.

>To what do you attribute your amazing success at breeding mites?

This is not success,this is a hive that has not carried through the resistant traits yet is tolerant and will be put to good use.

>Regardless... It still seems amazing to me that Bob's colony has a level of infestation of 55% and the colony is still alive.

I am not surprised as 55% is my cut off to allow for varroa pressure and the hive is requeened or used for research methods.This one will get a two day old cell ( for full brood break) from a resistant breeder running 10-15 % end of season varroa infestation and proven honey yield over two seasons.

>Varroa researchers are always desperate to get that many varroa to test with.

After 5 years breeding for resistance I am having the same trouble and need mite pressure on the hives for selection and for my own private research.

>Have you any idea what mechanism the bees are using to control the mites?

Yes,there are a number,when one works with resistant bees you see these first hand.