JIM CONRAD'S
NATURALIST NEWSLETTER
Issued from Hacienda Chichen Resort
adjoining Chichén Itzá Ruins in
YUCATÁN, MÉXICO

December 4, 2011

SLIME MOLD IN THE WASH BASIN
Here at the beginning of the dry season leaves are falling, collecting in odd places, moldering, lending an air of seedy repose everyplace not swept on a daily basis. Leaves gather in my outside bathroom's corners, nightly dews soak them and en masse each afternoon they dry into a brown crust like a layer of burnt oatmeal in the bottom of a pot. You can see such encrustations in the bottoms of troughs of the clothes-washing station next to my pole-walled shower at http://www.backyardnature.net/n/11/111204p7.jpg.

In that picture, in the narrow trough on the right, on the back wall and toward the lower left, do you see that vague, wedge-shaped stain? A closer look is at http://www.backyardnature.net/n/11/111204p8.jpg.

That whole treelike structure is four inches tall (10cm). It originated in soggy, decaying leaf litter on the trough's floor and spread up the near-vertical wall, branching and rebranching as it went, the branches often reconnecting with one another, forming an intricate, even beautiful, network. At the branches' uppermost tips the ramifications have thickened and occasionally budded into tiny mounds. You can see a much-enlarged photo of one of the topmost strands showing a budding tip at http://www.backyardnature.net/n/11/111204p9.jpg.

This is one of the Earth's most poorly understood, even mysterious, life forms. It's not a plant, not an animal, not a fungus. In fact, there's much debate about what taxonomic kingdom it belongs to. In common terms we can say that it's a slime mold, possibly PHYSARUM POLYCEPHALUM. I pick that name only because the picture matches others of that species found on the Internet, and the species seems to commonly occur. However, there are lots of species in the genus Physarum, and many, many slime mold genera and families.

The fan-shaped item in the picture is the resting stage of the vegetative form, which is known as a plasmodium. Plasmodia are thought of as single, huge cells invested with only one membrane, yet containing within that membrane very many nuclei, which stream along with the cell's protoplasm as the plasmodium grows searching for food. The plasmodium surrounds its food and secretes enzymes to digest it.

If the streaming plasmodium dries out it forms a sclerotium, which is the hardened, immobile thing shown in our picture. The sclerotium can remain in this dormant stage for a long time. Once favorable conditions resume, it will soften and continue growing and wandering, looking for food.

If the food supply runs out, the plasmodium stops feeding and enters a reproductive phase. Stalks of spore-producing sporangia form; I assume that the volcano-like feature shown in the last photo is a sporangium. Spores are spread by wind. They can remain dormant for years.

When environmental conditions are favorable, spores germinate and release either microscopic, tail-bearing, or "flagellated," cells, or else microscopic, amoeba-like "swarm cells," which eventually fuse together to form a new plasmodium.

Don't let that information slide by you. It means that during the slime mold's life history, sometimes it's actually many independently living organisms moving about, but then those many things combine to form just one organism, the plasmodium. It's as people in a street crowd suddenly began merging with one another, eventually ending up as one enormous, wandering, hungry being.

The mysteriousness doesn't stop there. Physarum polycephalum's plasmodium has been documented doing certain things that simple organisms aren't supposed to be able to. For example, by repeatedly alternating a plasmodium's environment between cold and hot at 60- minute intervals, biophysicists at Japan's Hokkaido University found that the slime mould appeared to react on time even, anticipate the pattern, when the researchers didn't repeat the conditions for the next interval. The plasmodium somehow had "learned" to prepare for the coming change.

Plasmodia connect their many branches into networks capable of distributing resources among their parts as efficiently as roads in human cities. This has caused some experts to consider them the "ideal substrate for future and emerging bio-computing devices."

References to these and other studies on Physarum polycephalum can be found on its Wikipedia page at http://en.wikipedia.org/wiki/Physarum_polycephalum.

I've resolved to not clean out the right side of my clothes-washing station. My pleasure in having a Physarum polycephalum plasmodium sclerotium waiting there for the next rainy season outweighs any service the trough could provide.

*****

SWEETPOTATO HORNWORM
Last week a long, thick, succulent, yellow-green hornworm, the Cassava Hornworm, turned up on the Cassava, or Manioc, outside the hut. This week in the center of the little asphalt road running south of Pisté to Yaxuná a similarly long, thick and succulent but this time brown caterpillar turned up, as seen at http://www.backyardnature.net/n/11/111204hw.jpg.

At first both volunteer identifier Bea in Ontario and I thought this was probably the brown phase of last week's Cassava Hornworm. However, something not quite right kept gnawing at Bea, so she kept on looking. After a couple of days she found it:

It's AGRIUS CINGULATA, whose adult stage is known as the Pink-spotted Hawkmoth, and whose caterpillar stage is called the Sweetpotato Hornworm. It's in the same family as last week's Cassava Hornworm, the Sphinx Moth Family, the Sphingidae, but in an entirely different genus.

We don't have Sweet Potatoes here but the abundantly weedy, late-season cornfields on both sides of the road our hornworm was crossing were nothing less than theaters of morning-glory twinings, and Sweet Potato vines are just morning-glories issuing from oversized tubers. Once again we have a hornworm turning up exactly where it ought to be.

I read that Sweetpotato Hornworms feed both day and night, and pupate in a chamber in the soil. One to three generations per year may be produced. They're found from the southern US south through Mexico and Central America to northern South America. Sometimes in late summer the adult moths wander as far north as British Columbia and southeastern Canada, and have even turned up on the western coast of Europe. A similar south-ranging flight taking them far from their main distribution area takes place in South America.

*****

UNUSUAL MORNING-GLORY PEDICELS
Around the hut these days one of the most eye-catching botanical curiosities is what's shown at http://www.backyardnature.net/n/11/111204ip.jpg.

The pretty flower there, a morning-glory blossom, isn't the story, for nowadays the landscape abounds with an amazing variety of morning-glory vines in full bloom. In the picture, what's interesting is those six dangling, 2½-inch long (6cm) things forming what looks like an upside-down candelabra. I was lucky to get the 3½-inch (9cm) flower in the picture, for it was the last of the season, and helped me identify what the things beside it are.

It's one of several blue-flowered morning-glory species we have here with no generally accepted English name, IPOMOEA CLAVATA. The upside-down-candelabra-like items are four-seeded, spherical fruits held beneath much enlarged pedicels, or stalks. When the flower is blossoming the pedicel is much thinner. The moment the corolla falls off, the pedicel thickens until you get what's shown here.

Earlier we've looked at this species, so you can see what the fruiting bodies will look like next April at http://www.backyardnature.net/n/10/100404ip.jpg.

And you can see the fruit's spectacularly fuzzy seeds at http://www.backyardnature.net/n/10/100404iq.jpg.

When we looked at Ipomoea clavata earlier we reckoned that the oversized sepals -- much larger and thicker than among "normal" morning glories -- prevented nectar robbery by insects that otherwise might burrow through the corolla's soft tube to get at the nectar inside at the base of the flower, instead of going in through the front and doing their pollinating job.

That doesn't explain why the pedicels in our current picture are so thick, but I can make a wild guess.

Ipomoea clavata's unusually large, hairy seeds mature during the dry season when the vine's leaves are yellowing and drying, even falling off. I'll bet that the oversized pedicels serve as reservoirs for water and maybe nutrients to enable the seeds to keep developing even when the vine is dying back because of lack of rain.

*****

COTTON BOLLS FORMING
We've been watching the Tree Cotton in front of the hut as they mature. Our Tree Cotton page is at http://www.backyardnature.net/yucatan/treecott.htm.

When Tree Cotton's hibiscus-like corollas fall off, ovaries are left behind to mature into fruits, which in the case of cotton are splitting-open capsules referred to as bolls. Nowadays many ovaries on our Tree Cotton are on their ways to becoming bolls. You can see one enlarging ovary snugly nested in its shallowly five-toothed, black-dotted calyx, which in turn is held within three deeply toothed bracts, at http://www.backyardnature.net/n/11/111204gy.jpg.

The black dots are glands. I'm assuming that they issue some kind of chemical that repels potentially damaging insects.

When you cut longitudinally across a developing ovary, white pulp turning into cotton fiber is seen, as shown at http://www.backyardnature.net/n/11/111204gz.jpg.

At the left in that picture four or so shiny, white, elliptical seeds are enmeshed in white pulp in which no fiber is discernable, but in the larger, more mature ovary at the right I could tease the white matrix into wet, sticky, partially formed fibers. The ovaries have to mature a good bit more before they become bolls splitting open to release soft, dry cotton.

*****

SWEET ORANGES
What a wonderful time to be eating oranges. After the hot, rainy growing season of the last few months, the Yucatán's orchards luxuriate with dark-green-leafed trees festive-looking with innumerable orange adornments. You can see what our local oranges look like heaped in a bin at the frutaría in Pisté at http://www.backyardnature.net/n//11/111204og.jpg.

Notice that these very sweet, super-flavorful oranges at the peak of perfection for eating are not as orange colored as the tangerines next to them, or oranges in North American supermarkets. That's because the notion that a good orange must be very orange colored is a marketing ploy. Marketers tout the orangeness of oranges because it's easier to make oranges look orange than to deliver exceptionally tasty oranges to distant customers. People here are sophisticated orange eaters and they know that to determine a good orange you check for blemishes, you might feel the firmness, you smell them, but you certainly don't buy the orangest oranges.

Many orange cultivars exist, too many bred mainly with very tough, very orange rinds with shipping and marketing mainly in mind. The ones in the bin are especially thin-skinned and juicy, perfect for squeezing orange juice from, though I just eat them. Since this cultivar's peel is hard to remove, I've developed a special way of eating them.

First I cut them in half, then I push inward at the back of a half so that it splits in the way shown at http://www.backyardnature.net/n/11/111204oh.jpg.

Once the half is split as in the picture, it's easy to tug the wedges from their peel with the teeth. When I'm pressing the half from behind some of the juice packets burst, but when I'm pushing, on the other I'm slurping up all the sweetness. It doesn't matter that I get a seed from time to time, for it's all so sweet and sensuous that I even like the seed's mild bitterness, and the slight burning sensation where the peel touches my lips, and the juice that gets into my beard. How wonderful to have such oranges, and to be able to eat them exactly as I like!

The Orange tree is CITRUS x SINENSIS, "sinensis" meaning "Chinese," which explains why the local word for sweet oranges is "chinas." The Orange plant is thought to have arisen in southern China. Until now it's been debated whether Orange plants derive from a wild species no longer occurring in its natural state, or whether it's a hybrid. Early this year the issue was settled by a team of Chinese researchers using gene sequencing techniques. They determined that Oranges are hybrids between Tangerines (also called Mandarins), Citrus reticulata, and Pummelos, Citrus grandis. This study, which also reveals the ancestry of several other citrus taxa, is found online at http://www.sciencedaily.com/releases/2011/01/110118101600.htm.

Today the orange is the most commonly grown tree fruit in the world, and there's a world of cultivars to choose from. In the US, most of the oranges grown in California are either 'Washington Navel' or 'Valencia'. Florida's commercial cultivars are mainly 'Hamlin' (early); 'Pineapple' (mid-season), and; 'Valencia' (late).

Our frutaría oranges look like Valencias, known to be the cultivar most planted in the tropics, and one producing relatively small but very juicy, rich- tasting fruits that often don't develop a deep orange color.

*****

A THEORY ON FOOT SHAKING
I've always been a foot shaker. Sometimes I sit tranquilly reading a book while a foot spasms back and forth at two or three beats a second. Books on body language interpret foot shaking either as an innocent release of nervous energy, or a suppressed desire to leave. I'm far from a nervous person and usually when my foot shakes I'm very content where I am. Why do I do this?

In late afternoons, mosquitoes tend to enter the hut and for some reason settle on my feet and ankles. This got me thinking about fleas in Europe where my ancestors evolved for many centuries.

May it not be that untold numbers of generations of foot shakers, for whatever their foot-shaking reasons, survived longer and produced more offspring than non-foot-shakers, because disease carrying fleas and mosquitoes on squalid hut and cave floors were less likely to settle onto shaking feet than lethargic ones? The long-term result would be a fair percentage of humanity sitting around shaking feet, even in flealess and mosquitoless places.

*****

ELEGANCE IS A COMPOST HEAP
Deep in the still night I awoke to the odor of my compost heap, a bruised-purple smell wearing old lace; fermenting citrus. Usually the heap doesn't stink, but lately I've gorged on so many sweet oranges that the extra peelings and a few whole rotten fruits have thrown the system out of whack.

Beneath the mosquito net I lay thinking how elegant it was for a compost heap to tell me it was indisposed.

For, elegance, it seems to me, is something distilled from what's profound and permanent. Elegance doesn't compromise itself with fashion or impulse, but rather states its case simply and clearly in timeless and appropriate terms.

That's what my compost was doing, stating its case, making known in the middle of a cricketless night its yearning to return to that equilibrium -- to that Middle Path -- at which its community of mutually dependent and cooperating decomposers attain their greatest diversity and efficiency. And, in Nature, what urges are more timeless and appropriate than those? What is more elegant?

The very hue of the odor that night told me what was needed. It was the same required by all healthy compost heaps, as well as for all of Nature's living things, at least Nature as witnessed here on Earth: A properly balanced input of nutrients involving some kind of energy source, air and water. No formula for life is more timeless and appropriate than that. It's an elegant formula.

Early the next morning I dumped a wheelbarrow of brown leaves onto the imbalanced heap, mingling them with bright orange rinds and yellow banana peelings, and then I peed on the whole thing. In other words, I added energy (stored among the leaves' carbohydrates), carbon and nitrogen at a timelessly exact and appropriate ratio, and stirred in air and water.

How elegant I felt standing there peeing on my mound!

The next night the air pooling around the hut was sweet and musty. It was an earthy fragrance redolent of wellness, satisfaction and unspeakable elegance.

*****

Best wishes to all Newsletter readers,

Jim

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