these:
Poplar is the dominant source in temperate climates, I believe. It's therefore reasonable to assume that the properties of propolis gathered elsewhere, from different "ingredients" (sources), may differ from those of temperate-climate propolis. However, I do not deem it reasonable to assume that it is "useless". Bees collect propolis for a reason, and that isn't to mend our ills. If that propolis was useless, then they simply wouldn't collect it. Why bother? A bee collecting propolis is a bee not collecting nectar or pollen. Natural and artificial selection would both have driven bees from non-temperate climates to stop collecting propolis if it had no value.
That's basically my whole message. Propolis is transported on the bee's pollen baskets: do you need me to cite a study stating that the pollen basket cannot be used simultaneously to transport propolis and pollen? Much of that passage also includes a series of deductions. Should I cite Darwin in order to be able to suggest that natural evolution will tend to favor behaviors that increase fitness over behaviors that reduce it?
If it's that propolis gathered from different climates have different compositions, then that's from an article titled "Chemical characteristics of poplar type propolis of different geographic origin" (
http://www.apidologie.org/articles/apido/abs/2007/03/m6089/m6089.html):
The use of propolis in folk medicine contin-
ues to increase (Castaldo and Capasso, 2002)
as a constituent of “bio-cosmetics”, “health
foods” and for numerous other purposes
(Wollenweber and Buchmann, 1997; Banskota
et al., 2001). However, chemical studies have
revealed chemical variability among propolis
samples and the existence of different chemi-
cal types of propolis according to plant source
(Bankova, 2005b). In temperate zones all over
the world, poplarbud exudates(mainly of
Pop-ulus ***** L.) have been shown to be the
main source of bee collected resin. Undoubt-
edly, poplar type propolis is the most stud-
ied and the best known type of propolis, both
from chemical and pharmacological point of
view. The chemical constituents responsible
for its beneficial biological activities, and es-
pecially for its antimicrobial and antioxidant
properties, are well documented: flavonoids
(including flavones, flavonols, flavanones and
dihydroflavonols) and other phenolics (mainly
substituted cinnamic acids and their esters)
(Banskota et al., 2001).
And in the conclusion:
The results obtained in this study show that the
chosen parameters are meaningful for the evalua-
tion of poplar propolis quality. It is important to re-
member however, that other types of propolis have
different chemical compositions (Bankova, 2005a).
For this reason, all the above discussed conclusions
and criteria are valid for poplar propolis only, and
should by no means be applied to other propolis
types, such as Brazilian green propolis or Cuban
and Brazilian red propolis.
This article refers to other articles where you can read more about the brazilian green propolis and the red propolis. I do not have access to those right now, however.
As for the uses of propolis for the bees, it's described in a number of articles, notable "Increased brood viability and longer lifespan of honeybees selected for propolis production", where the title explains pretty clearly what the results of their experiment was.
Also, I'd point out that the article I cited also stated differences between different samples of the same climates. Indeed, it seems to say that mountain/non-mountain played a bigger role in poplar propolis divergences than climate of origin did. All the literature I come across also describes the propolis types in the way this article did. They don't say "temperate climate propolis". Indeed, "some significant differences (P < 0.05) were found but they did not follow any distinct geographic pattern", they go on to say as they compared samples from different countries.
Therefore, to go on and claim that "temperate-climate" propolis is the only good propolis sounds dubious to me, much as "north of Georgia" as a criteria of selection for what is suddenly not "useless" anymore. What articles did Dr. Vetaley Stashenko cite to support his claims? Did he also suggest that people in temperate climates don't use tar for their roads, too? What's he a doctor of, anyways? Almost all of the pages I find about him are invalid urls. No publication in credible reviews as far as I can tell. However, his name also kicks up the article "Brazilian Propolis: A Promising Adjunct to Dental Care, Cancer Treatment, Vaccines", which's text I can't find, but which also goes to disprove that only "temperate propolis" is medicinally useful.
Maybe some companies will only buy a very specific kind of poplar propolis from temperate regions. Maybe, for their own ends, it will be superior (or so they think). That doesn't make other kinds of propolis "useless".