I have never been able to catch Anacampseros flowers fully open, they seem to flower only under very particular weather conditions. Although I have heard that they flower in the afternoon and evening, the only time I have seen flowers was in the late morning and I always think "give it an hour of two and then it will be fully open". I go back later, only to find that it's closed!
This is the plant itself and as you can see, many buds, but never flowers.
Pink flowers are generally pollinated by insects but I don't know what purpose it serves for a flower to only be open for a few hours a day