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

August 22, 2010

AUGUST CUCKOO
Maybe you're familiar with that feeling that comes in late summer or early fall when days are definitely growing shorter, the sky's haze has cleared out leaving a deep blueness, and in the resulting contrasty world the skin-crisping sunlight is intense, and coolish shadows are satiny black. We've had a little of that feeling here this week. I don't know whether the feeling always comes at this time of year, or if it's just a transient state.

Up North during the season of this feeling, that's when you often see birds molting, and I'm seeing the same here. For example, the other day I saw a Squirrel Cuckoo who'd completely lost his tail, and the rest of his plumage wasn't in a great shape, either. It was early morning after a big rain the previous evening and a drippy night. He perched spreading his wings against the drying morning sunlight as seen at http://www.backyardnature.net/n/10/100822cu.jpg.

Squirrel Cuckoos usually bear very long, impressive tails accounting for most of their body length. You can see a nice picture of a normal looking one at http://www.backyardnature.net/yucatan/cuckoosq.htm.

That last picture is prettier but somehow the first one engages me more, because it so well captures the feeling of our soggy but brilliant mornings, the welcome feeling of the day's first drying-out sunlight, and the vivid contrasts such days are full of.

*****

THREE FLIES OVER THE COMPOST HEAP
I keep a compost heap going so I can throw banana peelings there and pee on it. About once a week I add a bucket of dry leaves because the heap decomposes so fast it'd otherwise disappear. During the first few days of the heap's existence the pee smelled a bit, but soon the mound developed a microbial population especially rich in microbes that convert pee's urea and uric acid to ammonia and other less smelly forms of nitrogen. In my microbiologically balanced compost heap the uric acid doesn't hang around unconverted long enough to cause a stink.

So, last Monday right before dark I was standing peeing on the compost heap when I noticed that on the underside of a leaflet of Spondias mombin three plump, big-headed, greenish flies were doing what you can see at http://www.backyardnature.net/n/10/100822fl.jpg.

It looked like each was depositing a layer of white silk or foam over the leaflet's undersurface. My drawing close enough to take the picture didn't seem to upset them at all. I just left them there as darkness came on, planning to keep an eye on those white spots. In two days, here's what one spot looked like: http://www.backyardnature.net/n/10/100822fm.jpg.

Apparently, instead of the white patch being a smooth layer of silk or foam, it consisted of hundreds of very tiny, close-packed eggs or cocoons. Moreover, most of the white, baglike items appear to be split open, as if the larvae, or maggots, already have emerged from them, or maybe something tore the developing larvae from their bags. I'm not really sure what's going on.

One thing for sure, though, is that the white spots were deposited only on leaves about six feet (1.8 m) directly above the compost heap -- and not on any other leaves I could find. It looked to me as if the flies had left their eggs exactly where emerging offspring would fall through open air onto my compost heap with all its semi-decayed banana peelings, leaves and pee derivatives.

Volunteer bug identifier Bea in Ontario identified the flies as Green Hover Flies, ORNIDIA OBESA, described as a ubiquitous fly of the New World tropics. Apparently in earlier years when animal waste and garbage was less hygienically managed the species was much more common than it is now, even occurring in the southern half of the US. The maggots seem flexible in their food sources, being found in everything from the semiliquid stuff pooled in human outdoor toilets, to decaying fruit. One study showed that Green Hover Fly maggots can convert coffee-production waste into a protein-rich material useful in cattle feed.

When Bea sent me her ID, at first I wasn't sure she was right because the first Green Hover Fly image I Googled up showed the fly's two large compound eyes touching one another along most of their common sides. But you can see in our picture that our flies' eyes are widely separated. Googling more pictures I found that about half the flies shown had joined eyes while half were widely separated like ours.

Finally I remembered that in horseflies the males have contiguous eyes while the females have widely separated ones. It turns out that it's the very same with Green Hover Flies.

And that's interesting, since horseflies and hover flies aren't very closely related. A good guess is that the feature evolved independently in the two species. So what is there that makes widely spaced compound eyes more adaptive for the females of certain large fly species than for males?

*****

CROWFOOT GRASS
Lately we've looked at several grasses with flowering heads, or inflorescences, composed of several slender, spike-like racemes arising from atop a stiff flowerhead stem, or rachis. In the North the best-known grasses with that inflorescence construction are the crabgrasses and Bermuda Grass. There's a yard-wide (1 m), sprawling, foot-high patch of grass in front of my hut like that and it's none we've considered so far. You can see its blades and starfish-shaped heads at http://www.backyardnature.net/n/10/100822cg.jpg.

A closer look at one of its nicely symmetrical heads is at http://www.backyardnature.net/n/10/100822ch.jpg.

In that picture, notice how the tips of the flowerhead branch stems, the rachillas, pass a little beyond the flowers below them, ending in a sharp point. This feature helped me come up with the grass's identity, revealed below.

At first I thought the grass was a stubby form of Bermuda Grass, but then I examined the flower structure, shown in a raceme cross-section, at http://www.backyardnature.net/n/10/100822ci.jpg.

In the picture, spikelets are arranged along one side, the lower, of the rachilla, in two rows, and the spikelets alternately angle off right or left. Bermuda Grass's spikelets bear only one floret, while you can see that each of this species' spikelets have three or four. If you need to be refreshed on the relationship between spikelets and their florets, check out http://www.backyardnature.net/gr_flort.jpg.

This turns out to be Egyptian Crowfoot Grass, DACTYLOCTENIUM AEGYPTIUM, an African native but now occurring as a weed throughout the world's warmer areas, even deep into the US. It's easy to identify because of its star-shaped heads with much shorter and stiffer arms than crabgrass or Bermuda Grass, plus the before-mentioned sharp rachilla tips extending beyond the flowers.

In most of the world Egyptian Crowfoot Grass is just a weed, but in Africa it's valued as a famine food. If a lot of mature plants are growing together and dropping their sandgrain-size fruits, enough grains can be collected to provide some nutritious nibbling. There's a You Tube video by Deane Jordan on the matter at http://www.youtube.com/watch?v=03en6YXSE8k.

*****

LEADWORT BY THE POOL
At Hacienda Chichen's pretty entrance a reflecting pool is bordered by knee-high masses of a compact, weak-stemmed herb with bluish-white flowers, as shown at http://www.backyardnature.net/n/10/100822pm.jpg.

With those slender-tubed flowers each bearing five flaring corolla lobes, the average Northerner with a little garden-flower savvy would almost swear that it's some kind of phlox -- until noting what's shown at http://www.backyardnature.net/n/10/100822pn.jpg.

The slender, green calyxes below the bluish-white corollas are mantled with blunt, hairlike things. A close-up of those club-shaped "hairs" is shown at http://www.backyardnature.net/n/10/100822po.jpg.

Those are glandular hairs. If you touch the calyx with a finger you can feel its stickiness, and easily imagine what the hairs are for. If you're an insect looking for food and you're climbing the calyx, you'll get stuck among those hairs before you reach the flower's succulent sexual parts.

There's a genus of popular garden flowers recognized by the very fact that they look like phlox until you notice their glandular hairs. They're known as leadworts orplumbagos. The one at the Hacienda's entrance is the Cape Leadwort, PLUMBAGO AURICULATA, a native of South Africa but now planted worldwide in the tropics and subtropics, where it serves as a low hedge or ground cover. In the US sometimes it's grown in pots that must be taken inside during the winter.

"Leadwort" is something of a klutzy name for such a pretty plant. The name is based on the genus name Plumbago, bestowed by Linnaeus himself, which in Latin means lead. It's not clear what leadworts have to do with lead but I've read one theory that the plants were once used medicinally against lead poisoning.

Last November we reported on a weedy leadwort growing wild here at woods edges. That was Plumbago scandens, and you can compare it with its pretty African cousin at http://www.backyardnature.net/yucatan/leadwort.htm.

*****

PLANTING CAMOTES, JÍCAMAS, CHAYOTES & ÑAMES
Friday I found Luis busy working in the traditional Maya milpa, or cornfield, planting "camotes" (ka-MOH- tehs), or sweet potatoes. You can see how unlike Maya sweet potatoes are to what we have up North at http://www.backyardnature.net/n/10/100822g7.jpg.

In that picture the tubers are upside down, so those are roots on top, and the long thing at the far left is a stem bearing a couple of very small, heart-shaped leaves. Luis said that he'd just buried some tubers much larger than the big one in the picture, and that Maya sweet potatoes come in colors of white, yellow and purple.

The Northern sweet potato is IPOMOEA BATATAS, a member of the Morning-Glory Family, the Convolvulaceae, and this is the same thing, just one of the many variations of that much-cultivated, native tropical American species. In the online Flora de Veracruz, Andrew McDonald describes the species' tubers as white, yellow, orange, purple or red, and ranging in form from turnip-shaped to narrowed on both ends (fusiform). Of the species' complex genetics he writes that it's hexaploid, and that it hybridizes with closely related diploid species forming tetraploids, and that it produces populations exhibiting intermediate morphological features.

Next Luis showed me Jícama beans he'd carried from home in a plastic bag and was about to plant. They're at http://www.backyardnature.net/n/10/100822g8.jpg.

Jícama (HEE-ka-ma) is sometimes referred to in English as Yam Bean. It's PACHYRRHIZUS EROSUS, a member of the Bean Family, native to Mexico and Central America but much planted in the tropics worldwide for its starchy, highly edible tubers.

Next Luis showed me Chayote fruits he'd just planted at the base of a small, dead tree, which later the rampant Chayote vines will climb up. They're shown at http://www.backyardnature.net/n/10/100822g9.jpg.

Chayote is SECHIUM EDULE. I read that in English sometimes it's called Christophine but I've never heard that name. It's a member of the Cucumber Family. In the picture the things looking like sticking-out tongues develop into shoots that form much-branching vines that can completely cover a hut like mine, producing an incredible number of fruits like the ones in the picture. You boil them and they taste a litle like boiled potatoes. Some Chayote varieties bristle with soft spines, but these are the smooth ones. Chayote's tubers also can be eaten,

Finally Luis showed me the Ñame (NYAH-meh) he was about to plant. You can see Luis in his Virgin of Guadalupe cap holding half a rooting Ñame tuber at http://www.backyardnature.net/n/10/100822g-.jpg.

Ñame is DIOSCOREA ALATA, a member of the Yam Family, the Dioscoreaceae. In English sometimes it's referred to as White Yam or Water Yam. In eastern North America at the beginning of winter often you see slender, frost-bitten vines at woods edges bearing straw- colored, Chinese-lantern affairs. Those vines are usually called Wild Yams, and they're in the same genus as Ñame, Dioscorea. Wild Yam tubers are very hard and small compared to Ñame's. Ñame is thought to be a native of southern Asia. Its tubers can be enormous. When Luis spread his hands to show how wide he expects his yams to grow, they were about two feet apart (60 cm), so we'll just see if he exaggerates much!

*****

MOON GARDENING
When I was kid back in Kentucky my grandfather Conrad put out his garden with reference to the Moon's phases. Down here the Maya very strongly believe in the influence of the Moon on the plants they grow. In college horticulture class I was taught that absolutely no scientific data exists proving that the Moon's phases affect the growth of garden plants, so since then I've never paid attention to the Moon's phases, and I've produced some pretty good gardens.

Because here I see gardeners so concerned about the Moon's phases, it occurred to me that since the last time I wondered about the matter a new source of information has come along -- the Internet. So, this week I Googled the matter. I found hundreds of pages telling how important it is to coordinate gardening with Moon phases, and how to do it, but, still, I found no reference to any legitimate scientific study proving any correlation between garden plants and the Moon.

I suspect that one reason belief in the influence of the Moon on garden plants remains so strong is that Moon gardeners often produce the best gardens. Probably the reason for that is that anyone concerned enough about a garden to carefully coordinate plantings with phases of the Moon also would carefully monitor the garden's needs and keep it well tended.

A good page discussing Moon gardening concepts is at http://kaykeys.net/spirit/earthspirituality/moon/moonseed.html.

*****

A RAINED-ON HUT
This week the rains returned, so on most evenings raindrops pattered on the hut's thatched roof as I lay inside the darkened mosquito net, listening. Inside the mosquito net, that's when I digest the day's happenings, go over discussions I've had, etc.

For example, this week I've thought about the North American who'd passed through pretty unhappy about having to return home after being awhile in the Yucatán -- having to return to the job, back to the house with all its maintenance and yard mowing, and, as much as anything, back to friends and family who haven't a clue about how one can live happily in ways other than gringo ways.

The Northerner seemed especially worried about this: That often people in our culture obsessively work their whole lives "planning for old age," but either die before they get old, or reach old age so wrecked or burned out by their work that they can't enjoy what they've worked so hard to have. Or maybe what they've prepared for themselves no longer pleases, or no longer seems necessary. I've seen that, but I've been on the fringes so long I don't really know how common it is. I suppose it varies from place to place, and subculture to subculture.

We ended our cogitations on the matter by concluding that, once again, it's the Middle Path one must tread. Prepare for the future somewhat, but struggle every day for time when you can do the things you really want to do, the things you're good at, the kind of work that really fulfills you. This all sounded so self-evident that it felt awkward saying it, especially as the conclusion to a long discussion. However, the visitor said that so few people really practice the idea that maybe it needs to be articulated more frequently, needs to be repeated more often in everyday life among everyday people.

The visitor left asking me this question: Which is closer to the Middle Path: The way things are done up North, or down here in Maya territory?

I just laughed, figuring the visitor already had an opinion on that. I was pooped from the day's tasks so I just returned to the hut, got inside my mosquito net, and listened to the rain.

*****

Best wishes to all Newsletter readers,

Jim

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