ooohhhhh ... I have NO idea what to tell you about this. FIRST ... I feel very strange in saying anything at all to YOU, one of the most knowledgable of the "experts" I have run into here at the forum. But just on the off chance that the smallest part of my experience with bees (mostly "sweat" bees ... we don't get too many "honey" bees here as this is cattle country, and not farm country) will mean something to you, i'll continue.
And It is my profoundest wish that I not appear condescending here and that I am NOT putting myself forward as an "expert".
MY outside cacti are all in the greenhouse, some of which flower all year long, and I, for the most part,
choose to manually pollinate my cactus flowers ... in an attempt to assure that as many as possible get pollinated. I don't know what I would do if my collection was as big as yours. Manual pollination would take forever ... Maybe you could experiment with a
small batch. But now a curious thought occurs to me out of the blue ... I thouight bees were attracted to the colors produced by ultra-violet light, and NOT nectar? That they
take advantage of the nectar, but were
attracted by color?
I am puzzled by the fact that you say the bees seem to ignore your cacti. Are you CERTAIN of this? Do NONE of your cactus flowers have the petals curl inward as pollinated flowers will do? Like the flower in the picture below indicated by the big blue arrow?
![027.14 2016-11-17 223304.jpg](./download/file.php?id=57441&sid=f4f2d4946f78712d368f552ed098e044)
- 027.14 2016-11-17 223304.jpg (145.22 KiB) Viewed 10270 times
Despite my propensity to want to manually pollinate mine by hand, the bees DO visit even my greenhouse cacti. A "sweat bee" (i have NO idea why they are called that, unless they are attracted to a persons sweat) in the flowers of my Mammillaria hahniana.
![027.09 2016-10-29.JPG](./download/file.php?id=57439&sid=f4f2d4946f78712d368f552ed098e044)
- 027.09 2016-10-29.JPG (105.27 KiB) Viewed 10270 times
The following links are interesting articles about what bees are attracted to. I THINK you will find them VERY interesting.
http://www.springer.com/about+springer/ ... -1408347-0
http://www.abc.net.au/news/science/2016 ... es/7959382
https://bees.techno-science.ca/english/ ... t-bees.php
http://www.sciencemag.org/news/2017/10/ ... tract-bees
And this one has suggestions on how to attract MORE bees.
https://www.thespruce.com/bee-plants-1401948
I really hope I'm not pounding things into the ground here, but these next four articles talk about bees and cactus flowers
https://uanews.arizona.edu/story/cactus ... ed-flowers
https://buzzybeegirl.wordpress.com/2008 ... fuzzy-bee/
http://hownabout.com/cactus-pollination/
https://opportunitymuse.com/cactus-flow ... llinators/
OHHHHH!!!! Here's another thought that just this instant occurred to me. The flowers of plants E V O L V E D to attract pollinators ... and cacti are NEW WORLD PLANTS (north, central and southern americas, along with some islands) ...
so what if the bees that naturally occur in Lebanon just don't know what to do with new world flowering plants that are NOT naturally occurring in Lebanon??????
That might (at least partially) explain why your cacti are not attracting as many bees as your other plants. Or maybe I'm just too ignorant to be speaking on these matters.