September 16, 2012
SPIDER WITH A GORGEOUS ABDOMEN
On a typically hot, windy, sun-baked afternoon while beating stone-hard clods into dust in a spot where eventually I wanted to sow a winter crop of turnips I noticed a slight commotion between wires atop the deer-fence. It was a medium-sized, dark spider wrapping something in silk. You can see her and her silk-tied package at http://www.backyardnature.net/n/12/120916ss.jpg.
In the dazzling sunlight I couldn't see what she'd wrapped up but once the image was on the laptop screen it was clear that she'd been wrapping up an empty spider exoskeleton, probably her own. I don't believe that spiders eat their exoskeletons, so what was going on here? Whatever the case, our spider must have just shed her old "skin" so now her colors and designs were particularly vivid, as shown at http://www.backyardnature.net/n/12/120916sp.jpg.
Designs on the abdomen were especially beautiful, so I got a close-up, shown at http://www.backyardnature.net/n/12/120916sr.jpg.
I couldn't identify the little beauty so I posted her picture at BugGuide.Net and within a couple of hours a spider fan in British Columbia said she was most likely NEOSCONA OAXACENSIS, often known as the Western Spotted Orbweaver, found throughout the warmer US states through Mexico and Central America to Peru in South America. Pictures of the species on the Internet don't perfectly match ours, but the species is known to be variable, plus, so soon after shedding, our spider's colors may not have been fully developed. Other pictures show more colorful spiders, but with fewer intricate designs on the abdomen.
Isn't it something that such delightful patterns and designs can suddenly be offered to a sweaty guy beating clods with a shovel on a dusty plot of land like this?
EURASIAN COLLARED DOVES
One of the first sounds catching my attention when I arrived here was a certain soft but guttural rrrrrrrrrrr which seemed very familiar but completely out of place in southwestern Texas. It was the call of the Eurasian Collared Dove, STREPTOPELIA DECAOCTO -- which I strongly associate with chilly, often rainy spring mornings during past lives in Germany and Belgium, where such calls often issued from trees and bushes. Hearing them wasn't a complete surprise because for years wild Eurasian Collared Doves have been turning up here and there all across the US. About five years ago my uncle in Owensboro, Kentucky told me that one day several appeared at his feeder. Still, I hadn't expected them in such an isolated spot as Uvalde County, southwestern Texas. You can see that they're really here at http://www.backyardnature.net/n/12/120916dv.jpg.
That black collar around the back of the neck and its whitish underparts make it easy to identify. However, there's another species, the Ringneck Dove, Streptopelia risoria, often kept in cages and sometimes escaped into the wilds, that's practically identical. However, it's the Eurasian Collard Dove spreading across America so explosively, so I assume that that's what our picture shows. I suspect that Eurasian Collared Doves have been released here intentionally because they are larger than all other local doves and some people like to hunt and eat them. In Texas you need a hunting license to shoot them but since they're an invasive species there's no closed season on them and no bag limit.
A century ago Eurasian Collared Doves occurred mainly on the Indian subcontinent, Turkey and the Balkans. In the early 20th century they expanded across Europe and North Africa, and by the mid-1950s they'd reached Great Britain and Norway. In the US they arrived in southern Florida in the early 1980s and by 1995 were found throughout the US Southeast. The first free-flying, Eurasian Collared Doves in Texas were spotted in 1995.
So far no studies indicate that Eurasian Collared Doves are significantly displacing native species, though in some places they do out-compete and replace other invasive dove species.
COASTAL PLAIN TOAD
This week while I was painting an outbuilding a toad hopped into my life. You can see what he looked like on our community park shelter's cement floor at http://www.backyardnature.net/n/12/120916gc.jpg.
Just last month when we looked at an American Toad in Mississippi we saw that for identification purposes a toad's "cranial crest" configuration atop its head is very important. Therefore, this week I was sure to photograph my visitor's crests, as shown at http://www.backyardnature.net/n/12/120916gd.jpg.
The cranial crests are the narrow ridges looking like slender wires inserted just below the skin originating near the nose tip then passing just behind the eyes, and forking. You might find it interesting to compare this configuration with that of last month's American Toad's at http://www.backyardnature.net/n/12/120812td.jpg.
Notice how our visitor's cranial crests extend much closer to the nose tip than the American's, and that the shorter arm of the fork behind the eye is much longer than the American's short arm. Also our toad's parotoid glands -- the big bumps below the crests -- are smaller than the American's, and vaguely triangular instead of bean-shaped.
This cranial crest and parotoid configuration is exactly that of the Gulf Coast Toads we've met several times in Mexico. Moreover, my old US field guides leave no doubt that what we have here is exactly the Gulf Coast Toad.
However... Since my field guides' publications those pesky gene sequencers who can determine an organism's true identity by looking at its DNA have determined that US toads with cranial crests like ours are a different species from the Gulf Coast Toad, which is strictly Mexican and Central American. Our toads with such cranial crests are to be known scientifically as BUFO NEBULIFER, and some experts are trying to establish the English name for that species as Coastal Plain Toad. So, the same US frogs that before the gene sequencing paper was published in 2000 were known as Gulf Coast Toads, Bufo valliceps, now are called Coastal Plain Toads, Bufo nebulifer.
Our Coastal Plain Toads, by the way, also extend deep into Mexico. The ones we saw in Querétaro were apparently Gulf Coast Toads.
So, that's how it goes. Spend a whole life calling something by a name, then somebody comes out with an obscure paper and you have to begin calling it something else.
Coastal Plain Toads aren't the only critters who like the cement floor of the community's park shelter. In early mornings you're likely to see slender, eight-inch-long (20cm) lizards starkly patterned with narrow, alternating pale and dark lines quietly resting on the cement floor, basking in the warm sunlight. You can see one doing just that at http://www.backyardnature.net/n/12/120916rr.jpg.
A closer look at the front end is afforded at http://www.backyardnature.net/n/12/120916rs.jpg.
On the farm in western Kentucky I grew up with a very similar lizard, the Six-lined Racerunner, Cnemidophorus sexlineatus, common in the US Southeast and south-central states. However, this is a different species, the most conspicuous difference being that the Six-lined Racerunner's black lines are solid black, while you can barely see that on our cement floor one the black lines are broken with indistinct pale spots. Also, Six-lined Racerunners tend to have brownish tails while the tail of ours is pinkish.
Our cement-floor lizard is the Texas Spotted Whiptail, CNEMIDOPHORUS GULARIS, endemic to Texas and small parts of adjacent Oklahoma, New Mexico and Mexico. Being in the same genus as the Southeast's Six-lined Racerunner, you can see that the two species are closely related.
As you might guess, our whiptail eats grasshoppers, spiders, termites and the like. He's a very fast mover who when disturbed runs a short distance, stops and checks to see if he's being chased, then either nonchalantly begins walking around or continues running. He's active during the day. As with all members of the Whiptail and Racerunner Family, the Teiidae, prey is located by sight, smell and sometimes by taste, the latter by means of a long, protrusible, deeply-forked tongue. All "teiids," as the pros call members of the family, are egg-layers.
TEXAS RED OAK
On the limestone hill in front of the house the vast majority of the trees are Ashe Junipers and Texas Live Oaks. The few trees not of these species really stand out, so it wasn't hard to notice when something completely new came along. It was an oak, similar to the Shumard Oaks farther east, in that its lustrous, bristle-tipped leaves were shiny and hairless below. However, its leaves were smaller, and Shumard Oaks aren't supposed to grow this far west. You can see the mystery tree's leaves at http://www.backyardnature.net/n/12/120916qu.jpg.
The tree's bark was deeply fissured and blackish, as shown at http://www.backyardnature.net/n/12/120916qw.jpg.
Beneath the tree it was hard to find acorns, probably reflecting the large number of animals who feed on them, but there were a few, looking a good bit like Shumard Oak acorns in that the nut was big and unusually broad at the top, as shown at http://www.backyardnature.net/n/12/120916qv.jpg.
In the online Flora of North America the tree keyed out to QUERCUS BUCKLEYI, commonly known as Texas Red Oak or Buckley's Oak, which is a species that science recognized only as late as 1985. Before then trees of the species had been thought of as merely part of the natural variation of the Shumard and Northern Red Oaks. Now that the species is known, it's described as occupying limestone ridges and slopes -- exactly like ours -- as well as creek bottoms and occasionally along larger streams from central Oklahoma south to here in southwestern Texas.
It's always a pleasure to meet a tree species new to me, to just stand and admire it and focus on how it's different from other species, and this week when I met my first Texas Red Oak, especially because it's endemic to such a small part of the country, the feeling was even greater.
Here and there along the Dry Frio River's limestone slopes you find smallish trees with pinnately compound leaves like those of an ash tree, except that the leaves arise only one per twig node (alternate) instead of two (opposite) as with ashes. Nowadays some of these trees are loaded with yellowish fruits, as shown at http://www.backyardnature.net/n/12/120916sz.jpg.
The fleshy, yellowish fruits bear single round, black, very hard seeds, as seen at http://www.backyardnature.net/n/12/120916sy.jpg.
We've encountered this tree before, down in Mexico's southernmost state of Chiapas, where we got a picture of what happens when you remove the fruits' skins and beat them in a little water. That picture is at http://www.backyardnature.net/chiapas/soapber2.jpg.
So, this is the Soapberry Tree, the same species encountered in Chiapas, but it's a northern variety more specifically referred to as the Western Soapberry. It's SAPINDUS SAPONARIA var. DRUMMONDII. In older books Western Soapberries are listed as Sapindus drummondii. In the US our variety occurs from Arizona to Louisiana north to Kansas and southwestern Missouri, plus it extends into northern Mexico. In central Mexico the type variety takes over and occurs in the Caribbean, Central and South America, plus extreme southern Florida and a coastal part of Georgia.
Chiapas's Soapberries grew into substantial trees but ours here average maybe 10 to 15 feet high (3-4.5m), though I read that in well watered, rich soil they can reach 50 feet (15m). I tried to froth up a good suds the way I did for the Chiapas picture but our fruits wouldn't get so frothy. Maybe I just got them too late in the season. However, the black seeds are as black and hard as the Mexican ones.
Of course the seeds have been used for making necklaces and buttons, but I always think of what Mexican kids used to do with them -- play marbles.
Beneath scrubby Ashe Junipers at the edge of a limestone ledge on the hill facing the cabin a dense, bathtub-size clump of slender, yard-long (1m) leaves sprouted from a rock fissure. Arising from the center of the leaves a spindly stem topped with a cluster of small fruits arced toward the valley directly below, as shown at http://www.backyardnature.net/n/12/120916no.jpg.
The fruits surprised me, for they were inflated, three-cornered capsules, as shown at http://www.backyardnature.net/n/12/120916np.jpg.
The grasslike leaves, only about 3/8ths inch wide (1cm) bore tiny saw-teeth, seen at http://www.backyardnature.net/n/12/120916nq.jpg.
I'd seen plants similar to this before, though different. You might remember the one found back in 2007 similarly perched on a limestone cliff high in the Eastern Sierra Madres of Querétaro, Mexico, but with a trunk, still shown at http://www.backyardnature.net/n/07/070119no.jpg.
Often these plants are known as beargrasses. They're the genus Nolina normally placed in the Agave Family, and the online Flora of North America says that about 30 species are known, of which 14 occur in the US, mostly in the Southwest but also in the Southeast. Ours keys out to NOLINA LINDHEIMERIANA, among whose common names are Devil's Shoestring, Ribbon Grass and Lindheimer's Beargrass.
This is a wonderful find, for the species is endemic to only a few counties here in southwestern Texas. Though it's common on limestone outcrops on this side of the hill (the other side has been "cleared" for cattle) the Flora of North America says that it is "quite infrequent and becoming more so as its habitat is destroyed through development or overgrazing."
LIMESTONE-LOVING MOUNTAIN PINK
On a hill's lower slope so little soil covered the crumbly limestone that hardly anything but a few wiry, drought-stunted grasses survived. However, right in the middle of this parched glade stood an ankle-high little wildflower bearing more bright, pink blossoms than such a little plant should have, and it looked surprisingly fresh and healthy, as seen at http://www.backyardnature.net/n/12/120916cy.jpg.
How could so few short, narrow leaves photosynthesize enough carbohydrate to produce so many flowers? It can only be that the plant is exquisitely adapted to this harsh environment, like a camel in the desert.
You can see a close-up of a single flower with its five yellow anthers spiraling in an unusual manner, looking like tiny hands, and a large, pale stigma-head held apart from the anthers on a bent style -- better to prevent self pollination -- at http://www.backyardnature.net/n/12/120916cz.jpg.
This little wildflower is ZELTNERA BEYRICHII, pretty enough to have acquired several common names, among them Mountain Pink, Meadow Pink, Beyrich's Centaury, Rock Centaury, Catchfly and Quinineweed. It's endemic just to parts of Oklahoma and Texas where it thrives in sandy, gravelly, limestone-based or granitic habitats on hillsides and in prairies, pastures and savannahs. It belongs to the Gentian Family, the Gentianaceae. It's noted to blossom from May to July, so maybe ours are reacting to an unexpected downpour experienced here a few weeks back. In older books it's listed as Centaurium beyrichii.
On the deer fence surrounding the five raised beds where all the mustard greens, turnip tops, bok choy, tatsoi and other greens I can eat are flourishing, there's a twining vine whose drooping clusters of pea-sized fruits are turning very prettily red, as shown at http://www.backyardnature.net/n/12/120916cc.jpg.
This is one plant NOT endemic to our little corner of Texas, but rather I know it well from back East. Just for the pleasure of seeing something special and familiar I squashed a fleshy red fruit between my fingers and looked at the seed, which you can see yourself at http://www.backyardnature.net/n/12/120916cd.jpg.
It's just like a snail's shell, right? Some people think it looks like the Moon, so the vine is called Moonseed, or more precisely Carolina Moonseed, as well as Carolina Coralbead, Redberry Moonseed, Carolina Snailseed, Coral Vine, and other such names. It's COCCULUS CAROLINUS, native to the US Southeast and just beyond. It's a vigorous, adaptable species able to grow at woods edges, along streams, and even fencerows and other waste places.
Moonseed flowers are unisexual and occur on different plants, so obviously with its fruits our deer-fence vine is female. Moonseeds are members of the Moonseed Family, the Menispermaceae. All parts of the plant are reputed to be poisonous to humans, though birds eat plenty of the succulent-fleshed fruits, spreading the plant far and wide.
Certain indigenous American tribes used Moonseed medicinally for blood ailments, probably following the "Doctrine of Signatures," a primitive notion occurring worldwide based on the assumption that plants "signify" to us the use they are to serve us. Since the Moonseed's most conspicuous field mark is its blood-red fruits, it must be "signifying" that we can use it for blood ailments. Of course the things of Nature are the way they are for reasons other than their utility to humans. Nature simply doesn't work the way the Doctrine of Signatures assumes.
FEATURED ESSAYS FROM THE PAST:
"Odor of Freshly Ground Wheat," from the May 15, 2005 Newsletter, at http://www.backyardnature.net/n/p/050515.htm.
"Odor of Yellow Jessamine," from the February 3, 2002 Newsletter, at http://www.backyardnature.net/n/p/020203.htm.
Best wishes to all Newsletter readers,
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