October 22, 2017
SLIME MOLD ON HORSE MANURE
Early the first morning of my recent week-long visit with a friend near Tepotzlán, Morelos in high-elevation south-central Mexico, we went walking in his orchard so I could admire his plantings. I might have disappointed my friend when my very first show of excitement wasn't one of his wonderful trees, but rather a pile of horse manure. It was thickly covered with tiny translucent globes held atop hairlike stalks, each globe topped with an even smaller black sphere, as shown at http://www.backyardnature.net/n/17/171022sm.jpg
A closer-up view better showing the very slender, transparent stalks, the dewy, glass-ball-like globes, and the black spheres atop the globes is at http://www.backyardnature.net/n/17/171022sn.jpg
These are slime mold fruiting bodies. Slime molds are one of the most mysterious and interesting of all kinds of living things, not animals, not plants, not fungi, but something else entirely. They're Amoebozoa living by their own rules.
I have no idea what kind of slime mold we have here, but it's clear that we're seeing a good example of the "stalk phase" of the species. Here's how the stalk phase fits into a typical slime mold's life cycle:
First you have a single cell, a kind of amoeba, prowling about searching for bacteria, which it takes into its body, and digests. A well fed amoeba divides in two, and those two cells further feed and eventually divide, on and on, until some kind of hard time comes for the colony. Maybe the bacterial food runs out, things dry out, or temperature goes out of whack.
When this happens, the individual slime mold cells, the amoebas, start migrating to a certain point where they join with their neighbors, maybe a million of them, all converging and merging into one another to form a swirling mound.
Now the mound begins behaving as if it were a single organism. It forms something like a bullet-shaped slug the size of a sand grain, slithers to someplace that feels right, and after several hours the slug turns into a blob.
Then the blob starts forming a slender stalk, atop which a globe is formed. That's what we're seeing in our photos, though our species produces smaller, black globes atop the transparent ones, and I just don't know how to interpret that. It must be a special feature of this slime mold species. The globes atop regular slime mold stalks contain amoebas left over from the stalk-forming process, and these globe amoebaes form dormant spores. The spores await some kind of event that will splash, knock or carry them to a new bacteria-rich location where they can start the life cycle over again.
One of the most interesting features of the above scenario is that the amoebas forming the stalks die. Evolutionary scientists wonder how any species can evolve in which part of the population must commit suicide in order to help others of the community reach the spore-producing stage.
Online, you can watch a video entitled Watch Slime Molds Creep and Crawl Like Alien Slugs, produced by Princeton's John Bonner.
A more detailed description of a typical slime mold's life cycle, with good photos, charts and drawings, is at MetaMicrobe.com.
A deeper look at the evolutionary dynamics involved in slime mold life history is at DiscoverMagazine.com.
Also I surprised my host by not recognizing a certain 20-ft tall tree with very distinctive, palmately compound leaves, and producing large, conspicuous fruiting heads, as shown on a branch at the tree's top at http://www.backyardnature.net/n/17/171022sc.jpg
One of the tree's palmately compound leaves is nicely displayed at the picture's top, right corner. Notice how the stem-like petiolules of the leaf's many leaflets converge at the top of the leaf's stiff petiole. You can see a close-up of some fruits at http://www.backyardnature.net/n/17/171022sd.jpg
"It's a Schefflera," my friend told me, "often seen as potted plants in houses up North, and in gardens in warmer areas."
Scheffleras are members of the Aralia Family, the Araliaceae, which often produce palmately compound leaves like these.
It turns out that my friend was only half right. The Schefflera commonly grow up North as a houseplant, and famous for tolerating neglect and poor growing conditions, is Schefflera arboriola, native to Taiwan. My friend's tree near Tepotzlán was a larger species, SCHEFFLERA ACTINOPHYLLA, native to Australia, New Guinea and Java, and much grown outside in tropical climates worldwide.
My friend's Schefflera actinophylla is sometimes known as Umbrella Tree, Octopus Tree and Amate -- names shared with other species. In the tree's native environment, its fruits are eaten by many bird species, and animals such as Musky Rat-kangaroos, Red-legged Pademelons, and Spectacled Flying Foxes.
In Florida and Hawaii the species has become an aggressive weed-tree.
PAPER WASP NEST UPDATE
At http://www.backyardnature.net/mexnat/wasp1.htm we've kept track of a big paper wasp nest dangling exactly over the door of my hut back in the Yucatan. We've watched the nest enlarge and get heavier, dangling closer and closer to the top of my bald head as I pass below, until finally with a forked pole I lifted it higher.
After my two weeks of traveling, when I returned to the hut the first item I checked was the status of our wasps. The big paper nest hang where it was supposed to be, but all the wasps were gone. Not a single one circled around the nest. When my Maya-worker friend Gener came for a visit I asked if he knew what had happened to them. "Hormigas," he said. "Ants."
Gener had watached as the big, black wave of thousands of black ants washed across the landscape. They'd entered my hut, found, dismembered and carried away spiders and scorpions in the hut's thatch, and they'd climbed each tree around the hut, including the wasp-nest tree. Discovering our wasps' nest, they'd swarmed over it, cut open the cells and plundered the wasps' precious larvae and pupae.
At http://www.backyardnature.net/mexnat/waspmex.htm, about halfway down the page, you can review a dramatic attack ants made on a paper-wasp nest dangling on my hut's thatch roof a while back at Chichén Itzá. Both then and now the wasp-nest-destroying ants were army ants, about whom we have a great deal to say and show at http://www.backyardnature.net/mexnat/armyant.htm
The smaller wasp nest I've mentioned hidden in bushes beside the hut's exit also is depopulated. Now I understand better why the hut's roof bears quite a number of abandoned paper-wasp nests, and why the nest I've enjoyed so much watching lately was placed in such an out-of-way spot as the very tip of a long, slender branch that eventually dipped too low for comfort.
Earlier, as I watched our wasps during their most robust building period, the impression had been that the nest just couldn't have been better protected and safe. But, never forget the ants. At least in the tropics, ants very often hold the trump card in any game of survival.
BEAUTY HAS A USE
Having returned to the rancho at Ek Balam, with my "node days" ended -- those days of introspection, self criticism and change occasioned by my 70th birthday -- I find myself less interested in generating words than ever. I touched on why in the last Newspaper, noting current political and social realities. Deeds, not words. Except that I just can't keep myself from expressing awe and reverence, to anyone who'll listen, with regard to Nature's beautiful things.
"Beauty." During the last two weeks of travel, beauty has taken on an added dimension for me. It came about because my friend in Tepotzlán kept good-naturedly pestering me to explain the premises on which I base my "Nature as Bible" philosophy of life, and spirituality.
In the end I had to admit that my belief system has no rational basis at all. My beliefs are neither self evident nor provable. However, thanks to my friend's badgering, now I realize that my life's philosophy and spirituality actually are rooted in beauty. Here's how that works:
Over the years, my philosophy of life and spirituality have coalesced around the notion that the transcendentally good feeling associated with experiencing beauty is positive feedback. It's positive feedback meted out by the Universal Creative Impulse, and it functions just as it does when you give a dog a treat for behaving properly. The dog wants more, so he tends to behave better in the future.
We humans feel a delightful buzz when we experience beauty, and we want more. This is exactly what the Universal Creative Impulse "wants," since those things and circumstances most necessary to the evolving Universe are what we humans find the most beautiful. The Universal Creative Impulse needs us to procreate so we can evolve to higher levels, so humans find few things more beautiful than prospective mates at mating time, and the wide-eyed offspring that result. Music and art that speak to us of higher meanings we find beautiful because higher meaning is the goal of the evolving Universe. Healthy, vibrant forests are beautiful, so we want to protect them, which the Creative Impulse also wants, since humanity's evolving mentality won't go anyplace if the Earth's biosphere is destroyed, us along with it.
Putting this insight into words may make me seem ridiculously dreamy headed. However, the more I think about the concept, the harder it is to find anything wrong with it. In fact, it's much more believable and inspiriting than what's postulated by religions and other world views I've encountered. And, why shouldn't the Universe nudge along its evolving mental components with positive feedback such as the good feeling associated with experiencing beauty?
Beauty has utility, then. It's like a compass on a large ship, infallibly informing us of our lives' correct course.
A life filled with beauty is itself a beautiful thing; a life void of beauty, is on the wrong track.
Best wishes to all Newsletter readers,
All previous Newsletters are archived at http://www.backyardnature.net/n/.