... now, following on this long night literature review

https://link.springer.com/chapter/10.1007/978-3-319-60637-8_2
(there is PDF available online)

"Finally, there is no evidence that bees consume resins or propolis. It is
not
recommended that beekeepers feed propolis solution to bees. Because of the
highly
antibacterial and antifungal properties of propolis, it could risk killing
the beneficial
microbiome in bees’ guts that is so critical to their health and survival."

which is oposed to what Staments propose out of his fungus concoctions ....
mmmm
but they didn't or haven't done any feeding experiment.

https://www.ncbi.nlm.nih.gov/pubmed/28468244
(also available online as PDF)

One hypothesis is that social immune behaviors, such as the collection
of plant resins and their deposition in the nest as an antimicrobial
propolis envelope, evolved to
compensate for deficiencies in innate or physiological immunity. Supporting
this notion, there is some
evidence that propolis may reduce impacts of mycotoxins produced by fungi
[29]. In this case, feeding
propolis extracts, rich in flavonoids and phenolic compounds, to adult
honey bees reduced adverse
effects of exposure to toxins produced by Aspergillus, a common hive fungus.

The therapeutic value of propolis for honey bees has been understudied.
Most studies have
concentrated on the high in vitro activity of propolis from various regions
of the world against two
pathogens: Paenibacillus larvae, the causative agent of American foulbrood
(AFB) [15,19,21,79–81]; and
Ascosphaera apis, the fungal agent of chalkbrood disease [16,21,73]. Early
studies on the therapeutic
effects of propolis on individual bees and colonies yielded positive
results when propolis was fed to the
bees in sugar solution (e.g., [80,81]). In these studies, clinical signs of
AFB in field colonies, and number
of P. larvae spores in honey stores were reduced when bees were fed
propolis in sugar syrup. Feeding
bees propolis would be similar to administering oral antibiotics, but as
the antimicrobial properties of
propolis vary widely across plant sources and regions, oral application
risks under- or over-dosing
the bees and potentially harming the beneficial microbiota in bees’ guts
[82]. To our knowledge,
honey bees do not naturally consume propolis. Therefore, the mode of action
of a therapeutic effect of
propolis on colony pathogens is probably via volatile compounds [83] or
direct contact [84] either on
the hive walls, a barrier at the nest entrance, or along the rims of comb
cells.

https://www.sciencedirect.com/science/article/pii/S037811350
8001466?via%3Dihub
and we came back to latinamerica

... The aim of the present work was to evaluate the effect of a propolis
ethanolic extract (PEE) against *P. larvae* and its potential for the
control of AFB ...
... Toxicity for honeybees was evaluated by oral administration of PEE and
its lethal concentration was assessed. ...
... PEE was not toxic for bees at least at 50%. Field assays showed that 21
and 42 days after the application of the treatments, the number of *P.
larvae* spores/g of honey was significantly lower in colonies treated with
PEE compared to the colonies that were not treated with PEE. To our
knowledge, this is the first report about the use of propolis for the
treatment of beehives affected with *P. larvae* spores. ...


So I conclude that we need not only test feeding propolis to honeybee but
above all select for propolis collecting bees


*Abstract*
Propolis has been proposed to affect honeybee health. To test this
hypothesis, we initially evaluated propolis production in 36 honeybee
colonies. The three highest (HP) and three lowest propolis-producing (LP)
colonies had mean yields of 16.0 and 0.64 g, respectively. Queens and
drones from these parental colonies were crossed by artificial insemination
to produce five colonies each of the following crosses: HP♀ × HP♂, HP♀ ×
LP♂, LP♀ × HP♂, and LP♀ × LP♂. Colonies headed by HP♀ × HP♂ queens produced
34 times more propolis than those headed by LP♀ × LP♂ queens and five times
more than those from the other two crosses. Newly emerged bees were marked
to measure longevity, and egg and brood counts were made to determine brood
survival rates. The colonies with queens derived from crosses between
high-propolis-producing colonies had significantly higher brood viability
and greater worker bee longevity. We conclude that colonies that collect
more propolis are healthier and have longer-living bees.

*Increased brood viability and longer lifespan of honeybees selected for
propolis production (PDF Download Available)*. Available from:
https://www.researchgate.net/publication/277401452_Increased
_brood_viability_and_longer_lifespan_of_honeybees_selected
_for_propolis_production
[accessed Mar 09 2018].

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