Friday, June 1, 2018

Fishing for Pollinators!

Back at "Ketelsen West" in Tucson where it is deep into late Spring - the "5th Season" careful observers get here, where it is ungodly hot and made comfortable by the lack of humidity! It is supposed to be 108F this Sunday, yet the humidity will likely be somewhere close to 5%, making it entirely comfortable if you are at least out of the sun...

As for local flora, we are nearly to the end of the Saguaro blooming season, so there is little on the bloomin' calendar till the summer rains start another spurt of desert growth in 5 weeks or so. But wouldn't you know, my cereus repandus on the east wall of my house, spurt out 7 buds on 2 plants last week, and I enjoyed 3 consecutive nights of flowers of a couple per night! The photo at left shows a good number of them (click to enlarge image) about 4 or 5 days before start of blooming. By late afternoon you can spot the ones that are going to open that night, finally opening to their full 5 or 6 inch diameter (!) by 10pm or so. Once the sun hits them the next morning, the show is over and they close, either setting fruit or if un-pollinated, drop off in a few days... At right is a photo of the last night of blooming showing the spectacular flowers.



These flowers are so large and deep that they require pollinators with a long tongue or proboscis to be able to reach the nectar. There is a story where evolutionary biologist Charles Darwin predicted the existence of an unknown pollinator that could reach the bottom of a 12" long flower in Madagascar, and it took 130 years to prove his prediction! For these flowers, one need only wait and they will come to you. My favorite hunting technique is in setting up a camera on a tripod, taking flash photos in the dark on the off chance of catching one. It has worked well except rarely do I catch moths in the early May blooming - my suspicion is that they are not active in the pre-monsoon season... Here at left is shown a great photo I took a few years back of an uncurled proboscis of a rustic sphinx moth as it is about to dive in to feed on nectar. How deep does it go? Well, the photos at right (again, from years ago) show how far in they reach, and you can see their effectiveness as pollinators - they must get covered in it! The fact that it was in 3 consecutive photos indicate it fed for at least 90 seconds...



On Wednesday night I set up the gear and started it about 11:30, and awoke about 5:30 to fetch it. At 2 photos per minute, that corresponded to something over 700 photos. Did I catch any moths this time? YES! Exactly 2, their images shown here left and right. The one at left came in at 20 minutes after midnight, and the one at right came in at 3:07 am. Don't know if the flash scared them off, as they only appeared in a single shot each, but I've spent some nights in the May blooming without capturing a singe one, so am ahead of average in May!



And yet, pollination occurred - I can tell by looking at the stigma to see if pollen has been transferred from the anther... With the macro lens plus extension tubes at 5:30 in the morning, sure enough, it appears the stigma had a good coating of pollen as well as "moth feathers". Make sure to click on the image to show the full resolution. This was a 3-frame focus stack to slightly extend the depth of focus of the exposure...

SO success for the May blooming outing - rare indeed from my earlier excursions to catch anything. But it is always fun to try and see what you will catch. You bet I'll be back in the busier August and September blooming season!