JIM CONRAD'S
NATURALIST NEWSLETTER
Issued from Mayan Beach Garden Inn 20 kms north of Mahahual
on the Yucatán Peninsula's eastern coast just north of the Belize border,
in the state of Quintana Roo, MÉXICO
(N18°53'16.36', W87°38'27" )

September 4,  2011

A MORE TIGERY TIGER-HERON
Back in June we met one of our mangrove-loving Bare-throated Tiger-Herons. That was an adult, though, whose fairly inconspicuous stripes are still shown at http://www.backyardnature.net/n/11/110619ti.jpg.

A juvenile Bare-throated Tiger-Heron showed up this week with much more prominent barring, as you can see at http://www.backyardnature.net/n/11/110904tg.jpg.

This young bird will remind some Northerners of bitterns, which have similarly thick necks and also are heavily striped. However, stripes on bitterns run up and down while the tiger-heron's are horizontal.

*****

STARSNAIL
Having such poor vision, I concentrate so hard on not tripping over things that often I overlook what's right beside the path. That's when it's good to have along a kid like the one the other day on a Nature walk. What a wonder that he noticed so many things and wanted to know about them. He found the little shell at http://www.backyardnature.net/n/11/110904ss.jpg.

That's basically a snail shell with sharp dentations along the coil crests, so we know right off that we have gastropod (snails and slugs), which is a kind of mollusk; it's not something like a clam or barnacle shell.

However, the experts' say that maybe around 85,000 kinds of gastropods exist, so calling something a gastropod isn't saying much. Volunteer identifier Bea in Ontario steered me to the Turban Snail Family, the Turbinidae, but at that point it becomes harder to get a solid name for it.

A good guess is that we have the Longspine Starsnail, ASTRALIUM PHOEBIUM. Most pictures of that species show its shell bearing longer, sharper spines, but shells worn by waves look like ours. The main reason for guessing that it's Astralium phoebium is that that species is known to be common in our part of the world, from the North Carolina coast south through the Gulf of Mexico to Venezuela.

Longspine Starsnails have been recorded from shallow water to depths up to 137 meters (450ft). They graze on microalgae and diatoms. A website specializing in aquarium pets tells us that starsnails in general occupy rocky, rubble-covered environments. If they fall onto their backs onto flat, open sand they're unable to right themselves. They should be kept in aquaria with rocky, irregular bottoms.

*****

A BLUE & CLEAR-WINDOWED SKIPPER
Skippers are big-headed, thick-bodied, stubby-winged butterflies that quickly dart or "skip" about. With more than 3500 species worldwide, mostly in the American tropics, the Skipper Family, the Hesperiidae, is huge. We've seen lots of them, and they're mostly brownish, rather plain, and often hard to identify. And then there are some like the one shown at http://www.backyardnature.net/yucatan/mariposa/butt091.jpg.

That's a Belus Skipper, sometimes called Beautiful Beamer, PHOCIDES BELUS, and it's about the prettiest skipper I've ever seen. Not only does its powder-blue hue scintillate in sunlight but also the wings' transparent "windows" glow with whatever color stands below them, in this case the rosy pinkness of a Goat's-foot Morning-glory, a species blossoming fulsomely these days. Belus Skippers are found from the southernmost tip of Texas, where they accidentally turn up time to time, south to Costa Rica.

*****

SNOWBERRY
Lots of plants bearing white fruits are called snowberries. One of those, a shrub usually about eight feet tall (2.5m) is prettily fruiting along our roads nowadays, with white, pea-sized berries, as shown at http://www.backyardnature.net/n/11/110904cc.jpg.

A close-up of some of the black-eyed fruits is at http://www.backyardnature.net/n/11/110904cd.jpg.

This dense bush with slender, brittle stems and opposite leaves (two leaves at each stem node) occurs from Florida and Texas's Lower Rio Grande Valley through Mexico and the Caribbean into South America. Occurring in several English-speaking countries, it goes by other English names than Snowberry, such as Milkberry, West Indian Snowberry, David's Milkberry and Davis Root. It's CHIOCOCCA ALBA, a member of the same family as Coffee and gardenias, the Rubiaceae.

That name "Davis Root" points to a time when Snowberry's roots were used medicinally, as a laxative, diuretic, emetic, and against diarrhea. Years ago the plant was sold commercially as a medicinal plant in Europe and the US.

Snowberry is one of those bushes that acts like it wants to be a vine; it leans onto and grows over other shrubs and trees. Some gardeners espalier it or train it to trellises.

*****

CORAL PLANT
One of Marcia's plants flowering nowadays is shown at http://www.backyardnature.net/n/11/110904ru.jpg.

That's a native Mexican plant now widely planted in the tropics because it's so spectacular. Several English names are given for it, including Coral Plant, Coralblow, Fountain Plant, and Firecracker Plant. It's RUSSELIA EQUISETIFORMIS, a member of the Figwort Family, the Scrophulariaceae.

A close-up of its inch-long (2.5cm) flowers is at http://www.backyardnature.net/n/11/110904rv.jpg.

In that picture you can see that some corolla lobes are more up-turned than others. This makes the corolla bilaterally symmetrical instead of radial. If you looked down the corolla's throat you'd see four male stamens arching up to the corolla tube's ceiling, with the female style and stigma running along the tube's floor. That's a perfect configuration for a pollinator entering the flower to have pollen dumped on him from above even as he delivers pollen from other flowers on his underparts.

*****

A BEACH-STABILIZING GRASS
Hurricane Dean in 2007 was the third-most powerful of all Atlantic hurricanes to make landfall since records began to be kept. Its eye came ashore between here and Mahahual 20kms to the south. One day soon afterwards Marcia was surveying the damage near where the eye passed and noticed something interesting: A certain little mat-forming grass had done an amazing job protecting the beach from Dean's erosion.

Marcia dug up some of the grass and took it back to her place, to help protect her own beach from erosion. You can see what became of her planting in a shot of one of her palapas with grass-covered sand behind it at http://www.backyardnature.net/n/11/110904zo.jpg.

Notice how much higher the sand is beneath the grass than where the sand is unprotected.

At the grassy area's edge creeping rhizomes snake across bare sand capturing windblown sandgrains, building up the surface and stabilizing it, as seen at http://www.backyardnature.net/n/11/110904zp.jpg.

At first I had no idea what grass this was. However, now it's flowering and I can identify it. Close-ups of two inflorescence spikes, with the one on the right showing a zigzag rachis distinctive of the rye-grass-related group of grasses it belongs to at http://www.backyardnature.net/n/11/110904zq.jpg.

Finally, you can see the plant's much-branching, wiry rhizomes, its narrow, in-folding ("involute"), sharp- pointed leaves and stiff, spikelike flowering heads at http://www.backyardnature.net/n/11/110904zr.jpg.

It's a zoysia grass! Zoysia grasses are these grasses you see advertised under the "never-mow-again" heading. Originally from Asia, they form a dense, low carpet that never gets too shaggy. I've known about zoysia grasses for many years, but I've always associated them with moist or generously watered environments. I never dreamed that a zoysia grass could do so well in this hot, sandy, salt-sprayed beach environment.

From what I can see on the Internet, most garden centers in North America speak of zoysia grass as if it were one thing. In fact there are at least three different species of the genus Zoysia commonly sold in the US, plus there are numerous cultivars with names like Manila Grass, Japanese Lawngrass, Belaire Zoysia Grass, etc. Zoysia grasses in general have had their genes well scrambled by horticulturists. Not only have the boundaries between species been blurred, but even closely related grass genera have contributed genes to the mix.

Therefore, beyond calling Marcia's grass zoysia grass, I can't say exactly which kind it is. Of the three common species sold in the US, ZOYSIA TENUIFOLIA, or "Mascarene-Grass," looks most like ours because of its stiff, short, sharp-pointed, "involute" blades. Most zoysia grasses I've seen produce softer, flatter, blunter blades, though maybe our plants are wirier because of their especially hot, dry environment. Also, Zoysia tenuifolia is known to be widely used throughout the Caribbean Basin, though it is native to Japan. A fair overview of the Zoysia kinds appears at http://www.walterreeves.com/lawn-care/zoysia-species-and-variety-names/.

Marcia mentions one further attraction of her zoysia grass: Some neighbors stabilizing their sand with St. Augustine Grass have problems with mosquitoes breeding in the grass. That doesn't happen with her zoysia grass.

*****

PHEROMONE TRAPS ALONG THE ROAD
The other day four men passed through the area hanging onto roadside trees the yellow objects seen at http://www.backyardnature.net/n/11/110904ph.jpg.

In that picture the words on the bottom are "DANGER" and "PELIGRO," peligro meaning danger. Without touching anything I snapped a picture of the yellow card suspended from the center of the hood, shown at http://www.backyardnature.net/n/11/110904pi.jpg.

The top two lines translate to, "Synthetic pheromones and compounds of agricultural use."

The middle two lines read, "Pheromone: Palm Weevil." The words "Mayate Prieto del Cocotero" are the Spanish name for the insect known in English as the Palm Weevil, Rhynchophorus palmarum.

Pheromones are secreted or excreted chemicals, sometimes transmitted through the air, that trigger social responses in members of the same species. There are alarm pheromones, food trail pheromones, sex pheromones, and many other kinds. In this case, pheromones attract adult insects causing a disease, then in the bottom of the trap the insects eat poisoned bananas, and die.

You might remember our earlier piece on Lethal Yellowing Disease, or LYD, which has killed about 95% of this area's Coconut trees. That story is online at http://www.backyardnature.net/yucatan/lethal.htm.

Papers on the Internet peg the weevil larvae killing palms weakened by Lethal Yellow Disease as those of the Palmetto Weevil, Rhynchophorus cruentatus. That's different from the Palm Weevil, Rhynchophorus palmarum, which our pheromone traps are for. The Palm Weevil of our traps is known mostly for spreading a nematode disease called Anillo Rojo in Spanish, or Red Ring Disease, which kills Coconuts, Oil Palms, Date Palms, Papayas and Banana trees. Maybe the Palm Weevil is yet another newly invading threat to our Coconut Palms.

I chanced to meet a technician maintaining the traps, which must be done every two weeks. He had some dead weevils he identified as Palm Weevils. Two weevils beside one of my pinkie fingers for scale are shown at http://www.backyardnature.net/n/11/110904pj.jpg.

*****

ANVIL-HEAD THUNDERSTORM
That morning as I began jogging the stars were shining, with the merest glow of dawn off toward the east, over the ocean. When it grew lighter clouds began showing up as silhouettes and I could see that that day there was a good bit of "vertical development" -- columnar clouds all around the horizon soaring skyward. That meant lots of instability in the air, maybe leading to nice storms later in the day.

As the sky lighted up, one columnar cloud in particular caught my attention, its roiling, cauliflower-like top billowing upward fast, and vertical lightning starting to flash within, eventually ever ten seconds or so. As the sun rose, colors and luminosity of back-lighted clouds intensified, even as the air grew more electric. A magnificent thunderstorm was forming and I couldn't take my eyes from it all.

At a certain point any storm-cloud punching upward through the troposphere toward the stratosphere enters such thin air that the cloud must out from its own inner pressure, becoming anvil shaped. Cumulus clouds producing rain are called cumulonimbus, and cumulonimbus with anvil-top shapes are called CUMULONIMBUS INCUS, "incus" being Latin for "anvil."

Back at Marcia's, just as my jog ended, our cloud got its anvil-head, and I got its picture, as shown at http://www.backyardnature.net/n/11/110904th.jpg.

I can't see an anvil-head cumulonimbus without remembering Joe Putnam, my first roommate in college back in 1965, who one day came in from Climatology and asked me if I'd ever had a good view of a fully formed anvil-head thunderstorm. Before blurting out that like everyone else I'd seen dozens of them if not hundreds, it occurred to me that with Joe this might be a trick question. So, I tried to remember the last well formed one I'd actually had a good view of. I couldn't. I'd seen lots of them in books, mostly shot from airplanes, but, no, when I got to thinking about it, really I couldn't remember having ever having enjoyed a clear view of a fully formed anvil head, not in my whole life.

Joe was disappointed that he hadn't caught me. Then he explained that in our part of the world, the eastern US's humid interior, anvil head clouds were nearly always mostly or entirely obscured by haze or other clouds clustering around them. To have a good view of a fully developed anvil head, I needed to go west to more arid land, or south to Florida.

Speaking of lack of haze, right after taking the above picture I snapped a shot straight into the rising sun, which shows isolated, very distant clouds between us and the sun, visible because of lack of haze. See http://www.backyardnature.net/n/11/110904ti.jpg.

What I haven't figured out yet is why we have so little haze here over ocean water, and so much over dry land in places like eastern North America.

About an hour later, the thunderhead no longer thundered, and no rain fell below it. Its luminous head was spreading and dissipating, as shown at http://www.backyardnature.net/n/11/110904tj.jpg.

*****

DOWNSIZING
On an online National Public Radio program two folks were interviewed who'd recently had to stop spending so much money. One, who'd always eaten at least once each day in a restaurant, had begun preparing her own meals. The other had given up the car he'd used for going to work, and begun using mass transit.

Though it wasn't the point of the interviews, both downsizers said that at first they'd been depressed about having to give up things they liked, but later they were surprised to find themselves enjoying the changes. It was fun to take control of one's food and to prepare it just the way you like. It was a relief to forget about car maintenance and insurance premiums, plus it was enjoyable to read on the way to and from work.

All this sounds about right to me. For, we've all seen how excess of the kind people in our culture have become accustomed to bloats, weighs down, desensitizes, weakens, disorients, stupefies and makes crazy.

However, most of us also have personally experienced how frugality liberates, sensitizes, awakens, opens eyes, delights and enlightens.

How can this magical effect of frugality be explained?

I think it has something to do with frugality not being the opposite of excess. The opposite of excess is having too little to live a healthy and dignified life. Between poverty and excess, frugality is the golden Middle Path.

And many times here we've reflected on the magical, soul-satisfying qualities of keeping to the Middle Path.

*****

Best wishes to all Newsletter readers,

Jim

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