Correction:  In a previous post, when discussing the Australian research on
gut bacteria (https://rirdc.infoservices.com.au/downloads/09-120.pdf), I
posted:


> "The Aussie paper also indicates that the crop bacteria largely disappear
> in the absence of feeding."
>

An alert reader pointed out off list that I should not have used the word
"crop," but rather "gut".  I stand corrected.

The reader also questioned "i also don't see any reference in the paper to
gut bacteria "largely disapearing" in the absence of feeding....unless you
are talking about feeding the bees probiotic bacterial cultures, which is
entirely different from "feeding" as any reader would understand it."

I've reread the paper, and am not sure how to respond.  I'll cite the
relevant passages below, and let you decide for yourselves.  It appears to
me that the two strains introduced thrived on continual sugar syrup
feeding.  The authors did not look for other strains of bacteria during the
tests.  It is not clear to me whether the colonization of bacteria was due
to continual inoculation, or due to the sugar syrup feeding, since the
authors didn't test with syrup feeding alone.

For the first time (world-wide) probiotic feeding experiments were designed
and carried out to
determine if fed bacteria could be established in the bee gut. Bacillus and
Pseudomonas species were
marked with antibiotic resistance and fed to bees in apiaries in sugar
solution. It was found that high
numbers of bee gut bacteria could be maintained while regular feeding
occurred. However there was a
marked decline of the introduced bacteria over a period of time as soon as
feeding stopped. This
occurred more rapidly during summer feeding, compared to winter feeding.

The feeding of sugar solution seems to be the only artificial way to improve
recovery from
Chalkbrood disease currently. The increase in gut microflora with this
method again suggests this
to be a beneficial method for increasing gut bacterial populations.
Therefore feeding of sugar
solution can also be recommended in relation to gut microflora maintenance.

The Pseudomonas and Bacillus strains tested in these experiments gave
similar results.
For both Pseudomonas and Bacillus, the number of bees carrying the
artificially-fed bacteria reduced
in both field trials, which were carried out at different times of the year
(winter and summer), once the
feeding had stopped. However, this decline was far more rapid in the case of
bees fed in summer,
presumably because the bees at this time are foraging more, and thus that
there is likely to be a higher
turnover of bacteria in the bee gut during this period. This suggests that
the two test strains did not
colonise the bee gut effectively for longer-term survival. However it is
encouraging at this stage to
know that continuous feeding of bacteria to a bee colony introduces the
bacteria in high numbers to a
significant population of worker bees.

Randy Oliver

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