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

March 6, 2011

RATTLESNAKE
Deep in the dry season curled, brown leaves littered the grove's floor as I wandered among trees not paying much attention to where I was going. Maybe a not-consciously noted movement on the forest floor alerted my woolgathering mind to the 2½-ft-long (76cm) snake laid out before me, one whose diamondback pattern beautifully camouflaged him in the dry-leaf mosaic.

It was the Neotropical Rattlesnake, CROTALUS DURISSUS, a species occurring from northeastern Mexico south to Uruguay and Argentina, the distribution area being highly fragmented so that in some areas where you'd expect it, it's just not there.

We were away from the main tourist area but close enough to be of concern. I made the five-minute hike to the hut to get a bucket with a lid on it to put the snake in, and when I returned he was still there, not far from where I'd left him.

I held my walking stick before him to see how snappish he was, and he hardly seemed to notice. I passed the stick beneath his head, then farther back, until it was about midway beneath his body, lifted him up, and he behaved as if this happened to him every day. Gently I dropped him into the bucket, where he curled up, never once having shown fear or anger and never having rattled his rattles. Sometimes he looked around and once he flattened his head cobra-like, but that was his only hint that he noticed anything unusual happening to him. This mellow behavior is just like what I've experienced among Timber Rattlers back in Mississippi.

You can see the snake curled inside the bucket at http://www.backyardnature.net/n/11/110306rt.jpg

A close-up of the head showing an eye's vertical-slit pupil, as well as a pit between the eye and nostril, is at http://www.backyardnature.net/n/11/110306ru.jpg.

The pit is a heat-sensing organ enabling the capture of warm-blooded prey in total darkness. Such pits are characteristic of pit vipers -- rattlesnakes, copperheads, water moccasins, cantils, fer-de-lances -- all of which are venomous.

I carried the rattler a couple of kilometers from the visitor area and let him go. You can see him leaving at http://www.backyardnature.net/n/11/110306rv.jpg.

A close-up of his rattle-bearing tail tip is at http://www.backyardnature.net/n/11/110306rw.jpg.

It's untrue that rattler tails bear one segment for each year of the rattler's life. Segments are added to the tail each time the snake sheds. Young, rapidly growing rattlesnakes may shed three or four times a year while older snakes may shed only once. Sometimes if rattles grow too long part of it may break off.

This is the first venomous snake I've seen in this area. I'd been told that rattlers live here, but folks here are so uninformed, superstitious and downright hysterical about snakes -- swearing that nearly every snake encountered is venomous -- that I just wasn't sure they were here until now.

José the shaman says we have two races of rattler here, a "negro," or black, and a "rojo," or red. Ours is the "negro."

*****

TWO TURKEY VULTURES ON A POWER POLE
In the Yucatán we have four species of vulture: Turkey Vulture; Black Vulture; Lesser Yellow-headed Vulture, and; King Vulture. The first two species are common year-round in the skies over Hacienda Chichen. Lesser Yellow-headeds cluster around marshes, savannas, open grasslands and mangroves, so here in the dry, scrubby central zone they are rarely seen. Mostly white King Vultures likewise need moister, lusher forest than what we have here and don't deal well where forest patches are cleared, so they're very rare, and disappearing.

Therefore, on a cool morning as the sun came up, seeing two Turkey Vultures basking atop a power line was nothing special for here. It's just that they composed a nice picture, which you can see it at http://www.backyardnature.net/n/11/110306vu.jpg.

*****

MAYAN STINGLESS BEES SWARMING
A cloud of smallish, fast flying, buzzing bees swarmed outside a storage room's window up at Hacienda Chichen's colonial church, as shown at http://www.backyardnature.net/n/11/110306mb.jpg.

I put my hand into the cloud, as you can see at http://www.backyardnature.net/n/11/110306mc.jpg.

Though they really were bees, I didn't fear being stung because these were Mayan Stingless Bees, genus MELIPONA. Two species of stingless bee are cultured by the Yucatán's Maya, Melipona beecheii and M. yucatanica, with beecheii being the favorite. Though both species are stingless, they do tend to tangle threateningly in one's hair, and bite, as shown at http://www.backyardnature.net/n/11/110306md.jpg.

The bites don't hurt, though, mostly just scare you if you don't know how innocuous they are.

Often people refer to Maya Stingless Bees as melipine bees because they belong to the bee tribe called the Meliponini. That name avoids the question of which species is being dealt with, and hints of the fact that other species of stingless bees also exist. As well as in the Americas, stingless bees occur in Africa, Australia and Southeast Asia.

That day the bees were swarming outside a cluster of nest "pots" and remnants of pots in a cavity formed where a window's wooden lintel had rotted away, shown at http://www.backyardnature.net/n/11/110306me.jpg.

The pots look those of mud-dauber wasps, but instead of mud they're composed of a mixture of beeswax and various types of plant resin. In 2005 near Dzemul in northwestern Yucatán I photographed a smaller, neater cluster of pots where it was easier to see how thin the pots' walls were and how the pots structurally related to one another. That photo still resides at http://www.backyardnature.net/yucatan/mayabees.jpg.

The ancient Maya regarded stingless bees as sacred, and the bees' honey was very important to them. In the 112-page Madrid Codex, one of few "Maya books" escaping destruction by the conquering Spaniards, ten pages are dedicated to stingless bees.

These are fascinating and beautiful creatures but they're fast disappearing because of habitat destruction, insecticide use and competition from introduced bee types. You might enjoy reading the unusually informative Wikipedia page on stingless bees at http://en.wikipedia.org/wiki/Stingless_bee.

*****

POTTER WASP NESTS ON A LEAF
Also this week I happened to notice what's shown at http://www.backyardnature.net/n/11/110306po.jpg.

Those pea-size insect nests are indeed nests made of mud stuck to the silky, golden-brown underside of a vertically hanging leaf of the Star-Apple tree outside Hacienda Chichen's public bathroom. The leaf hung at head level and someone had picked the top, right pot's mud walls away revealing the cocoon from which, apparently, an adult wasp already has emerged. A couple of the pots lack escape holes.

By comparing pictures of these "pot nests" with others on the Internet, I'm guessing that they belong to a species of potter wasp, genus EUMENES. Eight species of Eumenes wasp are known in North America and who knows how many exist in Mexico, and which species we have here?

Even Bea in Ontario couldn't come up with much guidance. She did run across some general advice for identifying wasp nests made of mud, which she interpreted as suggesting that nest identification is difficult even for the experts. Here's the advice:

"... search an empty cell for the remains of spiders (legs, etc). If there are spider remains it is one of the Auplopus (genus) spider wasps (family Pompilidae). Pollen residue would indicate this is the nest of an Osmia mason bee. Caterpillar remains would indicate a wasp in the Eumeninae subfamily of Vespidae."

*****

ASTROCASIA FLOWERING & FRUITING
A small, very common tree here, about the size of a northern Redbud tree, is flowering and fruiting now. It's particularly interesting to me because it's unlike anything I've ever seen. A branch showing clusters of mouse-eye-size flowers, and leaves with petioles seemingly too long and stiff for them is at http://www.backyardnature.net/n/11/110306as.jpg.

A close-up of a yellow flower is shown at http://www.backyardnature.net/n/11/110306at.jpg.

One reason the flower looks so peculiar is that it is unisexual, bearing only female parts; stamen-bearing male flowers occur on separate trees.

Clusters of green, three-sided fruits dangle on the same tree as the above flowers appear on, shown at http://www.backyardnature.net/n/11/110306au.jpg.

The fruits appear to remain green until ripe, when the leathery husk splits into sections revealing three hard, bony seeds inside, as seen at http://www.backyardnature.net/n/11/110306av.jpg.

This is ASTROCASIA TREMULA, apparently having no name in English or Spanish, but known to the Maya by several names, including X Kay Yuc.

Whenever you see a three-sided fruit like that on a tree that's obviously an angiosperm, and the flowers are unisexual, you should think "Euphorbia Family" -- Euphorbiaceae, which is Astrocasia's family.

So many Astrocasia tremulas grow on and around the Hacienda's grounds that you assume that they're very common weed trees. However, Astrocasias are seldom heard of by non-specialists. The genus occurs only in tropical America, and includes only five species. Our species, Astrocasia tremula, is found only in widely separated, or disjunct, populations -- in the Greater Antilles, the Yucatan Peninsula, western Mexico, Panama, and Venezuela. Did the species once cover the whole area from Mexico to Venezuela, but then something such as a disease killed most of them out, leaving only these scattered populations? No one knows.

*****

DUCKWEED IN A HALTÚN
Haltunes (singular haltún), are special features of this area's landscape, which is developed upon limestone and referred to as exhibiting karst topography. A haltún is merely a smallish depression or hole eroded into the limestone, maybe the size of a small dog or a cow. Haltunes fill with water after rains. Since there are no aboveground rivers or streams in northern and central Yucatán, haltunes are important to wildlife and people needing water. You can see typical haltunes here at Hacienda Chichen at http://www.backyardnature.net/yucatan/haltun.htm.

Cenotes, or sinkholes with water in their bottoms, are much, much larger than haltunes, resulting from the collapse of limestone ceilings of underground rivers and caverns.

Haltunes hold water for weeks after a good rain. However, during the dry season often weeks pass without a drop of rain, and then most or all our haltunes dry up. Our last rain came about three weeks ago so now most of our haltunes are dry, but some deeper ones still contain rainwater. An especially deep, dog-size one in the Alux Grove holds several inches of black water and is frequented by Black Vultures who drink there, in the process leaving the water enriched by their poop. The surface of that Haltún is now carpeted with green duckweed, as shown at http://www.backyardnature.net/n/11/110306lo.jpg.

A close-up of some duckweed plants is seen at http://www.backyardnature.net/n/11/110306lm.jpg.

Floating flush with the water's surface, the flat, oval bodies are known as fronds. The larger ones are about 1/5th inch long (5mm). Each frond is a separate plant and you can see that they grow in clumps. Each clump consists of a larger frond or "mother frond," with smaller ones budding from larger ones. In time the thin, white "stipe" connecting the mother frond with the daughters rots or falls away, at which time the daughters become mothers with their own budding daughters. Duckweeds are flowering plants but the flowers are tiny and not present on fronds in the picture.

If you dip your finger into the water and retrieve some fronds so that they're upside down you see what's at http://www.backyardnature.net/n/11/110306ln.jpg.

Each frond sprouts a single root that dangles into the water below, but in the picture sticks into the air. Each frond having a single root instead of several is a field mark differentiating the duckweed genus Lemna from other closely related genera, whose fronds bear more than one root. The three conspicuous veins seen on each frond in the picture help distinguish this Lemna species from a dozen others, some which have only one vein or up to seven.

In the last picture notice that each root tip flares and flattens like a cobra's head. Root tips of most species don't do that -- they just end with a cylindrical, rounded tip. Such flaring, flattened root tips constitute an important field mark helping us identify what we have here as LEMNA AEQUINOCTIALIS, a species typical of warm-temperate to tropical zones worldwide, in the US sporadically occurring as far north as Nebraska and even Wisconsin.

The online Flora of North America assigns duckweeds to their own family, the Lemnaceae. However, other authors have begun lumping the Duckweed Family into the Aroid or Jack-in-The-Pulpit Family, the Araceae. Come to think of it, the Aroid Family also contains aquatic Water-Lettuce, genus Pistia, so duckweeds being included in the Araceae isn't really outrageous.

José the shaman says that in the forest when you find a haltún with duckweed on it, the water in that haltún will have absorbed medicinal qualities from the duckweed, and the water can be used against arthritis.

I don't see much duckweed here. In the North sometimes large areas of stagnate water are completely carpeted with it, as in some of the swamps back in Mississippi where ducks and other such critters eat plenty of it. I've not noticed Lemna aequinoctialis up there, so finding it here is a nice surprise.

*****

A WALK IN PISTÉ
In Pisté by late morning it's already hot and windy with summery cumulus clouds overhead. Coconut Palm fronds crackle in the wind, dust clouds swirl past, and heavy sunlight on sweaty skin feels good. Tourist buses stream through town headed for the ruins, pale faces peering from windows, but here on the backstreets mostly people are walking or on bikes. A pickup truck cruises by with a loudspeaker atop alternately blasting salsa music and praise for pineapples on sale.

An Achiote tree beside a low stone wall next to the street is loaded with brown, burry capsules. Break open a capsule, rub the reddish-orange seeds on your hand and you get reddish-orange stain, the color of spicy achiote paste used in many Maya dishes. Tangles of Night-blooming Cereus cactus scramble atop other stone walls. Grackles screech and clack and whistle from deep inside a big Strangler Fig, and Social Flycatchers, shrill and piercing, call t-CHEER-CHEER, chee-TIQUEER. Little boys cheer as their black homemade kite ascends skyward making loops in ever- gustier wind.

Gliding, gliding, gliding, feeling bodiless, looking at weed flowers, picking up silvery-winged Monkey-Comb seeds, passing gaudy wall posters announcing a dance in nearby Xcalacoop, images of light and color drifting by accompanied by birdsong here, blaring radio there, fragrance of citrusy Lemoncillo flowers here, the woosh of wind there, always the wind.

Honestly I'm not sure whether my friend and I are fighting when I interrupt our talk saying, "Look at that black dog smiling at us." Seeing the dog's sloppy smile and sparkling eyes directed right at us, she laughs so hard that I know we're not. She's just sending into me one of those probes of hers to see what's inside me, unconcerned about what she disturbs, or what the consequences might be.

Back on the main street it's hotter and much louder, and dustier. A lady's sidewalk rotisserie billows dense white smoke when juices drip from reddish chicken-halves being flipped. We walk through the cloud, my friend feeling good calls to the señora, "¡Huele rico!" "Smells good" and inside the smoke we enter another cloud, this of loud Mexican hiphop with such unlikely lyrics and joyful energy and sexy imagery that she looks at me and says, "Let's eat here."

In smoke and hiphop and with tourist buses rumbling over a speedbump just feet away my friend's orange-red chicken-half comes with rice, slices of red tomato, green lettuce, white onions, and hotsauce in a black stone molcajete. The giardia I've been battling for three months seems to be acting up today, sharp stomach pains and I'm a bit dizzy and feel feverish atop all the heat, so I just drink cold water, and soon feel better.

Actually I'm not sure it's my giardia acting up, or just the way I feel when this friend shoots her probes into me, or when she's doing things like sitting next to me as vividly aware as I that this smoke and the diesel fumes and this crazy hiphop beat somehow is something worth cherishing, worth getting misty-eyed about when I think about it, something that's smiling and generous and good, and even though I don't like breathing smoke, don't like eating beside speedbumps with crossing-over busses and don't like nutty hiphop, I know that we're so profoundly lucky to have it all exactly as it is right here and now, never to be experienced just so, ever again.

*****

Best wishes to all Newsletter readers,

Jim

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