Pollination of Cypripedium acaule (Pink lady's-slipper orchid) by a Bombus species (Explored 4-8-2012)

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Yesterday, Walter and I conducted a botanizing trip with three gentlemen (I use that term loosely) from Georgia. One of them was my flickr friend, Alan Cressler. The other two, Steve Bowling and Max Medley, are friends of Alan, and were welcomed by us to visit some of our favorite natural sites in the upstate of South Carolina.

One of the places we visited was a Heritage Preserve where, in previous years, I had seen Cypripedium acaule (Pink lady's-slipper orchid) bloom. This year, they were three weeks early in their blooming! Just try to tell me that climate change is a myth.

Anyway, I was fortunate enough to witness the pollination of this wonderful slipper orchid.

The process is rather straight forward:
1. A pollinator (in this case a bumble bee) enters the flower through a natural, vertical slit in the front of the slipper (pouch).
2. Quickly finding out that there is no nectar reward, the bee attempts to escape.
3. But the only way is out is up the back of the pouch and through one of two tiny openings at the top.
4. As the bee manages to squeeze out of the opening (and it is a struggle), its back is first forced to brush against the stigma inside the pouch, but since pollen has not yet been deposited on the bee's back, fertilization does not take place. As it progresses further up the opening its back is forced against one of the two waxy caps which hold the pollen. There is one on each side of the top of the pouch. Through this process, pollen is deposited on the bee's back.
5. Once the bee finally manages to escape, it will soon visit another orchid flower, and it will go through the process again, but this time, it will brush against and deposit the pollen on the stigma -- thus completing the pollination process...

What an ingenious way for the orchid to work with a pollinator to accomplish reproduction!