One can clearly see the movements of the flower
I saw a vid of it happening and wanted to try it too.
The movement is rather quick and resets after roughly 10 minutes.

I believe this is to improve pollen distribution to insects because they dive in for nectar and trigger the stamen to close around it making sure it catches a lot of pollen when it the insects squeeze out. Its optimized so every size of insects gets dusted as the desert prolly only gives sparse insect population.



See attached avi for my version or join into chat for a high quality version as i cannot attach that here.
Its clearly visible around :30 and also if you compare the start to the end. The camera does not move so its clearly visible how the flower changed

Also the full cactus shot

That is amazing, thanks for showing me something new today!


Lynn (from the video) is always so happy. She also grows lots of Trichocereus and peyote. Could these two points be in any way related?

Likely

Thigmotactic anthers help ensure self fertilization. Your going to want to cut those off prior to the anthers maturing if you want to cross pollinate with another locality.