More fun with UV lasers: The Aloe Edition

Aloe bloom

Let me state up front that I hate Nerine Dorman, the acclaimed South African horror writer. This isn’t a minor hate. I have plans for a vicious and vile repayment for everything she’s done to me and for me, and she’ll have earned every last bit. This was the woman who, along with her husband, introduced me to the fynbos, the smallest and most fecund floral kingdom on the planet. They’ve forgotten more about fynbos flora, particularly aloes and euphorbias, than I’ll ever learn, but that’s not why I plan to gain revenge.

Aloe nobilis

It all started this spring, when my aloes started blooming. At this time, I only have two species on hand, A. vera and A. nobilis, and last winter’s repeated Icepocalypses did wonders for all of my South African and Australian flora. Instead of burning off or freezing off permanently, the cold snaps not only encouraged sprouting and growth in Roridula seeds I’d given up on, but it caused a bloom explosion in the aloes.

Aloe blooms
(As an aside, I’m regularly asked at shows by cactus and succulent beginners about their plants’ blooming or lack thereof. While many require at least some cooling period to encourage blooming, the biggest factor is ambient light. With most barrel cacti, regular interference from streetlights, porch lights, security lamps, and other artificial illumination throws off their circadian rhythms, even if it’s only for a few days during their normal blooming periods. I’ve also noted this in such common succulents as jade plants (Crassula spp.), and it’s absolutely vital for aloes. Protect your aloes from light pollution in the spring, and watch them go nuts.)

Aloe blooms
Now, things got even more interesting when taking a closer look at the blooms themselves. They closely resemble the blooms of indigenous North American plants that depend upon either hummingbirds or hawkmoths for pollination, and the confirmation that they had a similar attraction came when a ruby-throat hummingbird proceeded to give me grief when mowing the grass by the aloe planters. There’s a very good reason why Huitzilopochtli, the Aztec god of war, was often portrayed as a hummingbird, as these little monsters have no fear of man, beast, or god, and this one took severe umbrage at my interrupting his feed. Most people would look at the wonder of being attacked by a dinosaur in this day and age and move on, but I needed to know what set off the sort of response more likely to be encountered when haranguing a hummingbird’s nest.

Well, that night, I dusted off the UV laser flashlight used to view fluorescence in carnivores, and tried it on the A. nobilis blooms. The petals fluoresce slightly under UV, but the tips? Those glow a brilliant cadmium yellow, like a black light poster. Considering similar enthusiastic responses from hummingbirds from bladderwort blooms with comparable yellow fluorescence, this suggests either that blooms of this sort offer trace elements in their nectar needed by hummingbirds, or some other factor makes hummingbirds associate this sort of UV glow, and remember that hummingbirds can see well into the UV spectrum, with particularly good food. Time for more research, or at least time to pass on the observations to botanists and ornithologists who can examine things further.

Aloe bloom spike junction

With that observation, I then asked Nerine, without any other familiarity with aloe pollinators, about which birds might be attracted to the blooms. That’s when she informed me of sunbirds (Nectariniidae), which are enthusiastic aloe pollinators. Two groups of birds separated by the Atlantic Ocean, attracted by the same floral cues for the same reasons, and a group of plants able to be pollinated by a bird group from the other side of the planet for precisely that reason…so do the birds call the shots, or the flowers?

Aloe blooms
This is why I hate Nerine as much as I do, and why I’m not going to rest until I come out to her house and talk her to death. At the same time as all of this, I lucked into a copy of the absolutely incredible book Fynbos: South Africa’s Unique Floral Kingdom by Richard Cowling, Dave Richardson, and Colin Paterson-Jones, and now I know where my next trip outside of the US is going to be. As if I don’t have enough realms to research: now I’m addicted to studying fynbos flora, and I CAN’T STOP.

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