Interesting Varoa Study

[Murphy]

Hi,

I found this article and found it very interesting.

http://www.funpecrp.com.br/gmr/year2002/vol2-1/gmr0040_full_text.htm


Kieran

[naturebee]

Yes, intresting article!
But in the abstract they say:

"ABSTRACT. In Europe and North America honey bees cannot be kept without chemical treatments against Varroa destructor."

I'm on my 5th year keeping bees in North America without chemical treatments of any kind. smile.gif

Here' another article that was in Bee Culture:

Quotes from an article in January 2006 Bee Culture
In Research Reviewed by Steve Sheppard

"Selection and possibilities within honeybees -
Be careful what you select for."

-------->

A team of Italian and German researchers selected
lines of bees that tended to have either high or low
mite populations and then investigated whether
behavioral and physiological characteristics of bees
from these lineages could be correlated to mite
levels.

The results reported by the researchers showed that:

1) Mite resistance or tolerance as measured solely by
mite population levels was not readily correlated with
the various tested physiological and behavioral
honeybee characteristics.

2) There was no correlation between the tendency of
the bees to remove pin-killed brood (hygienic
behavior) and the mite infestation levels of the
colony

3) They was no correlation between the number of
non-reproducing mites (SMR) and the level of mite
infestation.

4) There was no correlation between grooming and mite
levels.

5) There was no correlation between the percentage of
damaged mites collected on sticky boards and the level
of mite infestation.

However, they did find that both brood area (number of
brood cells) and the average honey crop harvested were
higher in each year of the experiment in the so-called
susceptible colonies compared to the resistant
colonies!

The authors caution the reader that hygienic behavior,
non-reproduction of mites (SMR) and grooming may be
traits that have limited value in a selection program
designed to produce mite resistant honeybees.

They further caution that it may be difficult to
select for honeybees that produce both vigorous and
productive colonies, yet have slow growing mite
populations. Their rational for the latter statement
is that mite population growth appears to be tied to
brood levels. Thus, selection for low mite levels
could actually select for bees that produce smaller
amounts of brood.

For example, by using mite infestation level (mite
counts) as the only selective criterion, the
researchers may have inadvertently selected for high
and low brood producing lines of bees.

Thus, their resistant bees actually may have been bees
selected to produce less brood and to be less able to
sustain mite population growth. Consequently, they
also would have been less able to collect a surplus of
honey.

-------->

[George Fergusson]

>For example, by using mite infestation level (mite counts) as the only selective criterion, the researchers may have inadvertently selected for high and low brood producing lines of bees.

Just another reason why so-called scientific studies need to be looked at critically and not just accepted on faith.

[Bob Russell]

George
Selective criteria is the key when breading varroa resistant bees.Here in New Zealand there are several of us working on this from different approaches.A couple of years ago those of us selecting for resistant bees were invited to take a look at the work of Allois Wallner who runs 700 hives in Randegg Austria.His selection work was from 1989-1994.During this time he examined some 17000 damaged mites.The results of his work was published in 1994 titled VARROARESISTENT all in German.I took up the offer and have his permission to repoduce his work.The English text translation is 53 pages and best read with reference to the book photographs and charts.I will be placing a CD of his work into our New Zealand National Beekeepers Technical library shortly.

[George Fergusson]

>Selective criteria is the key when breading varroa resistant bees.

I agree completely, but as the above study suggests, one needs to be careful what you choose for selective criteria.

> will be placing a CD of his work into our New Zealand National Beekeepers Technical library shortly

Good work. Will it become available on the internet in any way shape or form?