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

September 5, 2010

SNAKE IN A BUCKET
Alex of the grounds crew approached the hut warily carrying a white bucket and I figured he was bringing me a snake. It'd be a little one, though, because the fellows are afraid of snakes. But I like those little ones since usually they're the most interesting. I was right. It was a juvenile, and like so many species it was pale below but dark above, with no lines, bands or blotches. However, some distinctive-looking black facial markings on the head gave me hopes for naming it. The snake made no attempt to bite or get away as I reached into the bucket. You can see the little fellow at http://www.backyardnature.net/n/10/100905in.jpg.

A shot showing more of the body, including the black tail that was minus a couple inches of its tip, at http://www.backyardnature.net/n/10/100905io.jpg.

Those black lines on the face and the black tail nicely matched pictures in Jonathan Campbell's Amphibians and Reptiles of Northern Guatemala, the Yucatán, and Belize. It's a juvenile Indigo Snake, DRYMARCHON CORAIS. The species' Spanish name is Arroyera de Cola Negra, or "Black-tailed Arroyo Snake," an arroyo being a small stream that's dry most of the time. With that black tail and lack of blueness, the Spanish name for our snake is more appropriate than its English name.

Back in the 70s my Zoology teacher back at the University of Kentucky, Dr. Roger Barbour, kept a big Indigo he'd collected in Florida in a large metal, swimming-pool-like container near his office, and I remember that amazingly easy-going snake as being a very dark blue. However, Campbell describes adult Indigos in our area as having the front half of their bodies pale brown to olive-tan, becoming darker further back, so that the tail and about the last fourth of the bodies are blackish. There's been talk about recognizing our snakes as constituting their own tropical species distinct from the North's Indigos.

The thing about Indigo Snakes is that they can grow very large. Occurring in Florida and Georgia, they're regarded as North America's longest snake, the record being 103.5 inches (262.8 cm, over 8.6 feet). In the Yucatan we have two species that grow longer than that, Boa Constrictors and Tiger Treesnakes.

Indigo Snakes eat frogs, lizards, other snakes, birds and mammals. They don't constrict their prey like Boas. They just rush and seize their prey, then swallow it alive. That's often the way you find an Indigo -- by its prey's distress calls as it disappears into the snake.

Alex's little Indigo had been found in the tourist area, so he couldn't be returned there. I laid him on the ground beneath my Zinnias. Within two seconds he'd slipped between the hut's foundation rocks, and I figure that that's a good place for him.

*****

LEAFCUTTER ANTS EAT MY CHAYA
The edible-leafed Chaya in front of the hut has had a hard time. Within a week of my planting it caterpillars completely defoliated it. About a month after new leaves had been issued, leafcutter ants attacked, carrying away about half the leaves before mysteriously moving on to other plants. This week the leafcutters returned, and this time they completely defoliated it again.

Leafcutters cut away small sections of many kinds of leaves, carry the tatters back to their cavernous subterranean nest -- these ants' nest lies about fifty feet away (15 m) -- where the tatters are added to masses of other leaf tatters, and then a certain kind of fungus starts growing on the leaf-masses. The ants will feed on the fungus, not the leaves.

You can see an ant excising a section of Chaya leaf at http://www.backyardnature.net/n/10/100905lc.jpg.

A nice close-up showing how the spiny-backed ant holds his fuzzy head at an angle in order for his sharp mandibles to be in a better slicing position is shown at http://www.backyardnature.net/n/10/100905ld.jpg.

That last picture is worth studying. For one thing, it shows an ant cutting away the very platform on which she is standing, plus there's another ant beneath her holding to the same leaf section, that is about to be cut loose.

In fact, as I watched individual leafcutters reduce my poor Chaya to tatters, several times I saw ants cut away the parts of the leaf they were standing on. Usually they gradually moved onto the remaining part of the leaf, or at least managed to grab hold of the main leaf body before they fell, but sometimes they, along with their leaf tatter, plummeted to the ground. Sometimes the ant remained on the parent leaf while only the tatter fell. Sometimes the ground below the Chaya was almost green with fallen, unattended tatters, but as night fell ants began clearing the ground of dropped pieces, and carrying them away.

During these defoliations, if you watch a series of individual ants at work, you'll probably get the notion that they're a disorganized bunch. Often you see ants carrying tatters the wrong way, returning to the nest carrying nothing, or maybe just wandering around bumping into other ants, not seeming to accomplish anything constructive. Yet, at the end of the day, it's impressive just how much they've cut and carried away.

The continually flowing line of tatter-carrying leafcutters passes right below the green, immature Black Iguana I introduced you to last week, perched on his little rock. That iguana lets thousands and thousands of leafcutter ants pass less than a foot below his nose, but the moment a grasshopper or butterfly lands within twenty feet, like a streak he's off. I suppose it's the formic acid in the leafcutters that makes them unpalatable. However, the other day I did see a Peacock walking along a row of leafcutters crossing a corner of a parking lot just outside the ruin's entrance, and that bird nonchalantly pecked up quite a few.

A couple of days before the leafcutters attacked my Chaya they'd started on the basil planted beside my door. I happened to be sitting there just as the defoliation began. In a spray bottle I had a small bit of solution made from mashed garlic and Common Rue, which earlier had seemed to keep caterpillars off my cucumber plants. I sprayed the basil with what was left of that and the ants immediately stopped their predation. The unfortunate thing is that I have no more garlic or Rue for making a spray.

Having leafcutters so handy, I've been able to study what they do when it rains. From what I've seen, they don't do much of anything. If the rain isn't hard, they work through it. If it's a heavy rain, eventually they drop their tatters and hold onto something or get beneath something. I think a lot must drown. Within half an hour of the rain's end, individual ants start appearing on the old trail, some with tatters, and start back toward the nest. If a big puddle lies between them and their nest, they reach the water's edge, drop their tatters, and wander around until something happens. The tatters build up. Here puddles never last long, so within an hour or so they do reach their nest and all the tatters have disappeared.

During the dry season the leafcutters tended to work at night and disappeared during most of the day. Nowadays they work during the day and seem to quit with darkness.

What curious, mysterious things these leafcutters are. Really I understand why there's a discussion about whether the "leafcutter organism" is the individual leafcutter ant, or rather the whole nest -- individual ants analogous to red corpuscles flowing along arteries defined by scents on the ground. Information flows from the brain (the queen) not along neurons, but via chemicals passed from one ant to another. Who says that a living body can't be diffuse, and must be wet?

And if we can accept that an ant colony might constitute a single living organism, then there's Gaia to think about, and the Universal Unity...

*****

A PEACEFUL BUR-GRASS
Maybe you remember the vicious Coastal Sandbur grass, Cenchrus spinifex, that so painfully stuck into feet of those walking along the beach in Quintana Roo back in late 2008. You can see those wretched, spiny fruits at http://www.backyardnature.net/yucatan/sandbur.jpg.

Along the roads around here sometimes you see a member of that same genus, Cenchrus, with spiky fruits the way a Cenchrus fruit ought to be, but the spines are too soft and blunt to penetrate the skin. You can see a typical plant, with two flowering heads, at http://www.backyardnature.net/n/10/100905bu.jpg.

The spiky fruits, which hardly prick at all, are shown at http://www.backyardnature.net/n/10/100905bv.jpg.

This species isn't common enough in English speaking countries to have its own English name, though it can be referred to by the general names of bur-grass or sandbur. It's CENCHRUS BROWNII, a fairly common weed throughout much of the world's tropics, and supposedly introduced here and there in the US Southeast.

As always, it's so neat to see "variations on the theme," this time the theme being the genus Cenchrus. Cenchrus brownii's memorable contribution to the music that is Cenchrus is the relative softness and bluntness of its fruits' spines. Cenchrus in general is martial percussion and harsh, intimidating tonalities, but Cenchrus brownii comes on as an unforeseen strain on the French horn, masculine and offish to be sure, but much mellower than the music it's embedded in.

*****

TOMATILLO/ HUSK TOMATO/ TOMATE VERDE
Nematodes are killing all my tomato plants. As if to compensate for that, my Tomatillos, PHYSALIS IXOCARPA of the Nightshade Family, are four feet high (1.2 m), loaded with flowers, and fruits are starting to form. You can see a bug-eaten but vigorous sprout at http://www.backyardnature.net/n/10/100905ph.jpg.

A 3/4-inch wide (1.8 cm) flower -- back side on the left, frontal view on the right -- is shown at http://www.backyardnature.net/n/10/100905pi.jpg.

A back view of the flower is included so you can see the green calyx subtending the yellow corolla. In the genus Physalis the calyx is important because it does something extraordinary: After the flower is pollinated and the ovary begins growing into a fruit, the corolla falls off but the calyx begins enlarging rapidly, soon completely inclosing the fruit. The fruit becomes something like a small, immature, green tomato suspended inside the papery, balloon-like calyx, looking like a Chinese lantern, as shown at http://www.backyardnature.net/n/10/100905pj.jpg.

In that picture the image at the left shows how the "balloon" looks now hanging on the plant. On the right one side of the bladder has been torn away to show the immature, tomato-like fruit suspended inside. Eventually the mature, tasty "tomato" will fill the bladder. Back in Querétaro we bought such fruits in the market, and you can see a collection of them at http://www.backyardnature.net/q/physalis.jpg.

You can imagine the benefit a juicy fruit has from being suspended inside a bladder. Insects can't simply light on the fruit and begin eating or depositing eggs there. Also, the mature fruits of wild Physalis species I know up North fill only a small portion of their bladders, so the bladders are mostly filled with air. When the bladders fall to the ground, fall and early-winter wind often rolls them, with the fruits and seeds inside them, across the ground for long distances -- wind dissemination.

Up North wherever lots of Mexicans live sometimes these fruits are sold in supermarkets. Sometimes they are marketed as Husk Tomatoes but my impression is that nowadays they're usually marketed under the name Tomatillo, which is Spanish for "little tomato." Here they're called Tomate Verde, which means "green tomato." These names, plus names for the regular red tomato, change from region to region in Mexico.

Since regular red tomatoes are in the genus Lycopersicon, you can see that Husk Tomatoes/ Tomatillos, in the genus Physalis, aren't too closely related. However, they do belong to the same plant family, the Black Nightshade Family or Solanaceae, which also holds the potato, tobacco, chili pepper and petunias.

Around here everyone knows about the plant because the fruits are much used in a tasty but not hot, green sauce. They taste so good that I like to just eat them raw, one after the other.

By the way, maybe you noticed that the flower in the picture bore six calyx lobes, or sepals, six corolla lobes and six stamens. Flowers with a symmetry based on six usually are limited to monocotyledonous species such as those in the Lily, Iris and Amaryllis Families. In Nature, Physalis species -- usually weedy, and called ground-cherries or Chinese-lanterns -- almost always bear five-lobed calyxes and corollas, and five stamens. As was the case last week with the Star-Apple flower based on seven -- its symmetry also departing from its normal number five -- horticultural manipulation of important species often screws up the genes so that you get species doing weird things. It's the spots-on-cows phenomenon again.

*****

MAYA RAIN THAT BURNS
At the end of the dry season José the shaman brought me a potted Rue plant, warning that if I let the plant set out during the upcoming rains the leaves would "burn." Once the rainy season was well underway, one week suddenly the rains stopped and I had to start watering the garden by hand again. One morning as I went watering, just to have something to say as I passed Don Filomeno, I said, "We need some rain, don't we?" Don Filomeno looked at me with a look of surprise and replied, "No! Rain will burn our plants. It's best to have dry days and water each plant individually."

I've been asking my Maya friends what they mean by rain "burning" things, since obviously we can all feel that the rain falling each afternoon is cool, even chilly.

José the shaman, to be counted on for the "official" Maya line, like any good conservative, fundamentalist religious figure, interprets the words his teachers handed down to him literally. He says that rain falling through hot afternoon air soaks up heat and when it hits plants it releases that heat into them, burning their leaves.

Luis, who maintains the traditional milpa, or cornfield, and is as much a traditional Maya as José, has a different concept. To Luis, what burns our plants is rain that falls at night, and heavy dew. Afternoon rains don't burn plants since sunlight can dry them out. However, if rain falls onto an afternoon's hot ground, vapors arise and that's really bad news.

"The vapors carry the heat that's been stored up in the ground and scald the leaves," he says. "When you first touch ice, you can feel that kind of heat; the ice feels like it's burning. It's hot coldness... "

The Maya fear of "rain burn" is so great that, José tells me, commonly Maya women after an afternoon rain go splash well or city water on their most prized plants around the house, to wash the rainwater off.

Also José points to the fact that often, as with Spanish Plums, fruits with no holes apparent in their skins mature filled with worms. José explains this by saying that fruit worms start out as seeds, but when burning rain hits the flowers, the seeds turn into worms. When I tell him about insects laying eggs inside flower ovaries (the future fruits) with their very slender ovipositors, without losing a beat he counters that the worms always are there, but the hot rain activates them.

A Northern gardener looking at "rain-burnt" leaves recognizes classic symptoms of fungal disease -- dried-out, crumbling brown spots bordered by yellow on green leaves. Naturally at this time of year fungal diseases are rampant because of the combination of heat and humidity, which is exactly what fungi need to thrive.

When I was a kid on the tobacco farm in Kentucky during the 1950s I was told to never water the tobacco during the day or I'd burn their leaves. I think I finally got that figured out. Broad, thin leaves of young tobacco plants growing close together tend to stick to one another when wet, so maybe that blocks the leaves' air-admitting stomata. Maybe when the sun is shining and photosynthesis is taking place fast, needing quick gas exchange, cells of leaves with their stomata blocked die from lack of air, or build-up of toxins. Does anyone have a better suggestion?

Whatever the cause, I've certainly seen many tobacco (and lettuce) leaves on young, close-growing plants "burnt" after heavy dews, summer rains, and my own rebellious midday waterings. This "water-burning" notion is by no means restricted to the Maya.

*****

PLANTING LETTUCE IN ROWS
This Thursday Luis planted lettuce. Since he's using traditional Maya seeds I'm interested in seeing what the plants end up looking like. He sowed the seeds in very straight, evenly spaced rows. I broadcast my lettuce seed in beds, so I asked him why he uses rows. "That's the way it's done," he replied.

Probably most Northerners also plant their lettuce in rows, and I've never understood why. When you broadcast them, the seeds end up more or less evenly spaced with each seed having plenty of open area in which to develop. In rows, however, seeds get crammed so close together that they must compete with one another for limited space, water and nutrients in the row's vicinity, even while a lot of open soil between the rows remains unused. To each lettuce seed, every other lettuce seed is a "weed" competing for the plant's needs. Planting seeds in rows is like planting weeds with them.

Actually, probably I do understand why so many people plant lettuce and similar plants in rows. It looks more orderly and they think it's easier to tend. I agree that it looks more orderly, but lettuce in my beds needs no tending at all, other than the selective thinning I do as I pick what I need for salads. I bet that most people just unthinkingly plant in rows for the same reason Luis does: "That's the way it's done."

*****

A VISIT TO PISTÉ
At least once a week during the last ten months I've walked -- during the last month, biked -- into Pisté, mostly to buy fruit. By now lots of people along the way recognize me and we speak or nod to one another. I'd never thought that a place like Pisté might someday start feeling like a "hometown," but that's become the case. There's a view of Pisté's downtown area, with my fruit-buying place, the Frutería "Dorcy," just beyond the big blue truck at the right, at http://www.backyardnature.net/n/10/100905ps.jpg.

That picture was taken last Sunday morning at about ten o'clock. After a clear dawn, clouds already were curdling up for the afternoon downpour and the air was so hot and humid that drops of sweat constantly had to be shaken from the tip of my nose because they tickled. My blue shirt was dark-blotched wet, and stuck to my body.

At a little left of the picture's center you might notice a shaded clutter at the roadside where you can sit on the sidewalk and drink something cold, or go into the dark, loud tortillaría behind you and buy hot, freshly baked tortillas, or bucket-size masses of masa (moist corn paste) for baking your own tortillas over a fire, on a comal, back home. That's the way it is in Pisté, lots of unexpected juxtapositions, everything kind of a hodgepodge, really, all with a friendly, homey feeling to it.

Pisté extends two or three blocks away from both sides of the highway, which is Hwy 180 running between Mérida and Cancún. The farther from the highway, the more countrylike the streets become, the lusher the vegetation, the more thatch-roofed huts you see, the more goats and roosters you hear, and the more interesting the plants around people's houses. Streets generally end as weedy dirt trials continuing to ever-more rustic homes.

Actually, backstreet Pisté is vibrant: Gaudy-flowering greenery overflowing stone walls, kids everywhere playing, crying, peeping around corners, sounds of tortillas being patted into existence or maybe methodical tapping from shops chiseling authentic Maya wood carvings for sale in the ruins, dogs barking, a little girl in yellow shorts and a pink Tweety-Pie T- shirt coming down the street holding a clear plastic bag of crushed ice in one hand and a liter plastic bottle of black Coca-Cola in the other, behind her a muddy pig chasing a dusty turkey... The animation goes on and on, never ending, never going silent, and one never tires of gawking, of letting the mind float down street after street.

In fact, I used to think I'd like to live somewhere like that, in a simple little hut amidst such vivacious, colorful, congenial clutter. But, then I thought of the noise. If a house has a radio, it's played full blast, and the music is heavy on accordions unless there's a teenager in the family, and then it's hip-hop, boom-boom-boom, full blast. And on every street there's at least one dog barking all day and night, every day, year after year. And babies crying, everywhere, everywhere, so many colicky babies, plus all those crowing roosters, bleating goats and sheep, gobbling turkeys, etc.

But, that's how life so often is: You're attracted to something, feel like you really need it, but then you get closer and it starts driving you crazy. In fact, every trip to Pisté evokes in me that whole train of thought, about it being human nature to overlook problems associated with whatever it is you want really badly.

So, when I go into Pisté I'm always glad to experience the town's charm and friendliness, but then before long I'm more than happy to get back to my own world, which may not be as colorful and congenial-feeling, but at least I don't have to listen all day and night to colicky babies and accordions or hip-hop boom-boom-boom.

*****

Best wishes to all Newsletter readers,

Jim

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