I returned from the Midwest a few weeks back and was afraid that I'd missed the blooming season for the cereus repandus cacti on the east side of the house. Fortunately, as I rounded the corner, I saw about 20 buds that would provide about a week of blooms. The are remarkable flowers, attaining nearly 6" (15cm) diameter, with the blooms opening fully well after sunset, and on their way closed shortly after the sun hits them. So they depend on night time pollinators, and it has been a hobby of mine to document this "night shift" every year. Here is a link to
some of my favorite pollinator posts the last few years...
My first Friday night back I had gone to Phoenix to attend an astronomy club meeting, and returned after midnight to find 7 (!) flowers open, so set up my old Canon XSi (with built-in flash) to take a photo every 20 seconds through the remainder of the night. Starting about 1am, the camera ran unattended until about 5:30 when I went and stopped it - it was already getting light and was surrounded by bees, which take over after the moths stop coming. So yes, there were over 800 photos to examine! As shown above, the full frame covered 2 blooms to see if they worked them sequentially. It turns out I never saw one on the rearward blossom.
It was a long wait for the first visitor - the shot above at right was after 3am, 2 hours after the start. Hard to tell if the flash startles them or not. Some only stay for one flash, some for several. The one at left came only 2 minutes later, but I don't think it is the same one - the latter looks larger and I can't match any of the fine patterns... Then, almost 2 hours later one fed for 3 of the consecutive exposures. Looking much smaller than the moths in the other exposures, I have no explanation. I don't believe they grow as they age, so am mystified a little by their apparent smaller size. It looks to be the same species as the markings are nearly identical, the exception is that the above have 3 orange spots down the side and these smaller ones have 5...
A few minutes later I caught the corner of a wing, and the flash silhouette of another moth, so I'm counting 4 visits even though this one is marginal! About 30 minutes later the first honeybees came along and are the last to have their way with the flowers before they close shortly after sunrise. But even among these bees there are some interesting variations! At left is one of the few that had it's "fannypack" stuffed full with pollen already! Note I had repositioned the camera with macro lens for these shots with the ring flash.
The oddballs continued with the appearance of a large, black, fuzzy bee in one frame - I think is a female carpenter bee. In addition there was a small strange moth that also appeared in one frame shown at right. It appears green with brown trim. Unfortunately it wasn't in sharp focus, so remains a mystery - wasn't able to find anything close in Google images...
Finally shown here is the result of a night of pollinators... At left is shown the resultant stamen where the pollen is deposited and must adhere with a sticky substance. Individual pollen grains are resolved in this full-resolution 15-frame focus stack. Meanwhile the anther that normally is loaded with pollen look like bald, yellow raisins. At the start of the night they are fuzzy and loaded up with pollen grains. Make sure you click on the image to see it at full scale.
And here is a flower a few nights earlier that shows what the flower parts look like early in the evening, when the stamen (green fingers) are fresh and devoid of pollen at left, and at right the anthers are shown loaded with pollen...
So the bloom season has now ended, and continues again early next summer. The desert provides few blossoms for pollinators in the fall, so not much of interest coming up, but I'll be sure to be out next summer!
