JIM CONRAD'S
NATURALIST NEWSLETTER
Issued from the valley of the Dry Frio River on the
southern slope of the Edwards Plateau, northern
Uvalde County, southwestern Texas, USA

September 7, 2014

WRINKLED GRASSHOPPER
In the middle of a gravel road in the middle of the morning there sat the fairly large (1¾ inches, 45mm), boldly patterned grasshopper shown at http://www.backyardnature.net/n/14/140907gh.jpg.

Even though the bicycle had almost run over him, he hadn't moved a bit, so I circled back to see if he'd stay still long enough to be photographed. Not only was that image allowed, but also I got the top view of his back, which was nicely marked with a distinctive white X, as seen at http://www.backyardnature.net/n/14/140907gi.jpg.

While photographing, I hadn't noticed the red items on his back, or pronotum. I'm guessing that the red things are mites, possibly of the family Erythraeidae, composed of parasitic mites, some of which are known to parasitize grasshoppers, and when they do so they look just like what's shown in our pictures. Maybe this parasitization explains why our grasshopper was behaving so lethargically. A side view of the same part of the grasshopper appears at http://www.backyardnature.net/n/14/140907gj.jpg.

The grasshopper was so sluggish that I caught him, and was able to see that his hind wings when opened displayed yellow and black splotches, shown at http://www.backyardnature.net/n/14/140907gk.jpg.

Grasshoppers can be hard to identify, but both volunteer identifier Bea in Ontario and I came up with the same name, which is the Wrinkled Grasshopper, HIPPISCUS OCELOTE, occurring throughout Mexico except for the Yucatan and Baja Peninsulas and in the US common east of the Rocky Mountains and the desert southwest, where it inhabits prairies, pastures, and fields, only occasionally turning up in open woods. It feeds on a variety of plants but prefers grass. Its occurrence seems to be spotty and never in large numbers, so it's not regarded as of agricultural interest. Recently I'd heard of vast swarms of grasshoppers in the Texas Panhandle farther to the north and had thought this might be one of them, but guess not.

Though our Wrinkled Grasshopper's bold, dark patterning really stood out on the white gravel road, in grassy areas the species' camouflage is very effective. Moreover, members of the species make themselves even harder to see by entangling themselves in grass blades.

*****

TERSA SPHINX HORNWORM 
At daybreak each morning my neighbor Phred steps from his house and waters a long row of potted plants along his house's sunny side. Earlier this week one of his favorite plantings turned up as nothing but a pitiful cluster of nibbled-on stems, as you can see at http://www.backyardnature.net/n/14/140907x9.jpg.

In that picture, if you look closely, down in the lower, left corner there's a finger-thick, brown, juicy-looking hornworm hanging beneath a ravaged stem, and that's one of the culprits. A similar caterpillar was on the ground beneath the plant. A close-up of the caterpillar showing a handsome eyed pattern along its sides, a curious "square-scaled" design on the skin, and a "horn" at the end, is at http://www.backyardnature.net/n/14/140907xy.jpg.

Both caterpillars kept their heads safely tucked beneath folds of skin at their enlarged front ends, as shown at http://www.backyardnature.net/n/14/140907xz.jpg.

That picture also shows the big "eye" on the swollen front end, and of course this enlarged front with two big "eyes" might dissuade a potential predator from taking a stab at our little plant eater.

Normally I wouldn't even attempt to identify such a caterpillar because volunteer identifier Bea in Canada is much better at it than I, but this time I noticed something that might give me an advantage in the ID process. It's shown at http://www.backyardnature.net/n/14/140907x8.jpg.

That's a stem node on the plant the caterpillars had devoured. At this node two leaf petioles come together, so the plant's leave are "opposite," and above the two leaves are three stems, displaying a certain kind of stem branching not found among all plants. The most distinctive features, however, are the comb-like, upward projecting "teeth" arising from the flange-like item connecting the two leaf petioles, one comb on each side of the stem.

These are stipules. Some plants have them and others don't. Most stipules are like tiny leaves arising at the bases of leaf petioles, and they come in many shapes and sizes. Often they fall off the leaf once the leaf expands to full size, but not always. Stipules provide protection to leaves during their bud stage and shortly thereafter.

When you see such stipules connecting opposite leaves, you should think "Rubiaceae," sometimes called the Madder Family. It's a big family, but mostly tropical. Coffee plants and gardenias belong to it. However, the family is poorly represented in the Temperate Zone, so I figured that simply by doing an image search on the key words "caterpillar Rubiaceae" I might see a picture of our caterpillar.

And, I did. Our hornworm is the larval stage of the Tersa Sphinx moth, XYLOPHANES TERSA, a mostly tropical American month distributed from Argentina and Brazil north through northern South America, Central America, Mexico, the Caribbean area, and in the US from Massachusetts south to south Florida; west to Nebraska, New Mexico, and southern Arizona. Bea in Ontario came up with the same ID using her own approach.

The ButterfliesAndMoths.Org website states that this moth's caterpillar hosts feed on "Smooth buttonplant (Spermacoce glabra), starclusters (Pentas species), Borreria, Catalpa, and Manettia species." All these plants are members of the Rubiaceae, except Catalpa.

The Tera Sphinx moths these hornworms eventually will produce are large and brown -- with wingspans of about 2� inches (60-80mm). They begin feeding on flower nectar at dusk

*****

WALNUT SPHINX HORNWORM
Having photographed the above Tera Sphinx caterpillar I got to work painting a house, but first dirt needed to be pulled away from the foundation. And in the disturbed soil there turned up yet another large, brown hornworm-type caterpillar, but of a different species. You can see him in my paint-smeared hand at http://www.backyardnature.net/n/14/140907c2.jpg.

Lots of large, juicy caterpillars of this type display such diagonal lines along their sides, but the many tiny, evenly spaced bumps seemed unusual and therefore good field marks. Another noteworthy feature was the pointy head, much different from the Tera Sphinx caterpillar's, shown close up at http://www.backyardnature.net/n/14/140907c3.jpg.

Several caterpillar species are similar to this one so volunteer identifier Bea in Ontario shipped the pictures to the ButterfliesAndMoths.Org website, where in a few hours an expert had identified it and placed a new on the species' distribution map. The distribution map with our dot -- the southwestern-most large orange one -- can be admired a bit down the page at http://www.butterfliesandmoths.org/species/Amorpha-juglandis.

Our pointy-headed caterpillar studded with tiny bumps is the Walnut Sphinx, AMORPHA JUGLANDIS, which ButterfliesAndMoths.Org says feeds on "Walnut and butternut (Juglans), hickory (Carya), alder (Alnus), beech (Fagus), hazelnut (Corylus), and hop-hornbeam (Ostrya).

None of those host species were nearby where our caterpillar turned up, though here and there Little Walnuts, Juglans microcarpa, are found along the Dry Frio's banks where the river runs through fields of cobblestones. However, big Texas Live Oaks, Quercus fusiformis, shaded the ground where the caterpillar was found, and oaks belong to the same family as beech, where are feed upon, so maybe our Walnut Sphinx caterpillars feed on live oak, too. The adults, by the way, stay alive just long enough to have sex and the female lays eggs, so they have no functional mouthparts. Some sphinx moth species feed as adults while others don't.

Walnut Sphinxes occur throughout eastern US and southernmost Canada though they're absent from most of New England. They also extend into northern Mexico.

I read that Walnut Sphinx caterpillars make a squeaking sound when disturbed, but I heard nothing. Our caterpillar was an excellent squirmer, however, flexing back and forth so violently that the first spasm set off my own involuntary "let-go" response, and I almost dropped him. I bet that most birds with this caterpillar in their beaks would do just that after such a squirm.

*****

HOT GRACKLE
During these hot dog-days, birds often look as hot as one feels, and we're reminded that birds have several behavioral mechanisms for cooling off. For example, look at the Great-tailed Grackle at http://www.backyardnature.net/n/14/140907qu.jpg.

This bird is holding his wings away from his body allowing air to circulate around his chest area, sweeping away excess heat. Also he's fluffed out his neck feathers, allowing admittance of cooler air.

Most notable, however, is that he's walking around keeping his mouth open, "fluttering" his neck muscles, causing air to quickly rush back and forth through his mouth and throat so that moisture evaporates from his tongue, mouth cavity and throat. Basically he's panting like a dog, and for the same reason -- birds lack sweat glands. Dogs do have sweat glands, but they're concentrated around the foot pads, which doesn't help much keeping the body cool.

*****

TERMITES AT WORK
In last month's August 24th Newsletter we looked at our tiny, narrowly endemic termite Tenuirostritermes cinereus. Heads of that species' soldier caste possess long, pointed beaks from which toxins are shot at enemies. Our page on that termite is at http://www.backyardnature.net/n/a/termite2.htm.

The day I observed those termites, I only got to see them streaming across a small patch of earth and entering their hole. I hadn't been able to figure out anything about how the species makes its living, and very little information about it is available on the Internet.

This week in the same general area another colony turned up, and this time I got to see what appeared to be numerous workers (guarded by a few sharp-snouted solders) stationed atop certain thin, dry flakes of tree bark and dried-crisp flower-bud scales, seemingly chewing or cutting chunks from these materials. You can see this at http://www.backyardnature.net/n/14/140907at.jpg.

A line of these termites extending from this general area to their nest hole included several workers carrying what appeared to be material they'd cut from the debris shown in the picture.

That's not Earth-shattering information but, with this uncommonly observed, little known species, it's something, and I'm glad to post this information here, for future researchers.

*****

TEXAS KNOTWEED
On a muddy bank beside a stream connecting holding ponds in Cook's Slough Nature Park on Uvalde's south side, there was a small thicket of knee-high plants with exceptionally thin, wiry, straight stems bearing small leaves and tiny flowers, all fairly unnoticeable among surrounding grasses, as seen at http://www.backyardnature.net/n/14/140907pg.jpg.

A closer look at the stiff stems and modest leaves and flowers appears at http://www.backyardnature.net/n/14/140907pi.jpg.

Most flower were in their bud stage, and the buds were distinctively triangular in shape, or "trigonous," as shown at http://www.backyardnature.net/n/14/140907pj.jpg.

Bearing trigonous flower buds is a good field mark, but maybe an even more important one is the clear, cellophane-like, long-toothed "collar" below the flowers and surrounding the stem, shown in the above picture. The collar is an "ocrea," or "stipular sheath," and when you see such a thing surrounding a stem you should think "Buckwheat Family," Polygonaceae, sometimes also called the Smartweed or Knotweed Family. Most dicots, as opposed to monocots such as grasses and lilies, have flower parts in 4s or 5s, or multiples thereof, but the Buckwheat Family has them in 3s, like most monocots, and that's unusual.

After looking around awhile an open flower turned up, shown at http://www.backyardnature.net/n/14/140907ph.jpg.

This plant astonished me, for I'd never seen any member of the Buckwheat Family like it. Fortunately, the Buckwheat Family is finished in the online Flora of North America, so I could "key out" our plant. What I came up with amazed me even more. I'd thought the plant must be a genus I'd never heard of, but it was the commonly occurring smartweed/knotweed genus itself, Polygonum, and if you do a quick image search of that genus you'll see for yourself that not many smartweeds look like ours. For one thing, most smartweeds produce their flowers in densely packed, fingerlike spikes, not in few-flowered clusters apparently distributed along a leafy stem.

In Flora of North America's genus key our plant's characteristics were so outstanding that in the key for Polygonum the species keyed out within seconds. It was enough to note that the flowers' anthers were yellow, not pink to purple, and that the plant was a perennial, not an annual herb, as I'd thought all smartweeds had to be. You can see its woody base and perennial rhizome at http://www.backyardnature.net/n/14/140907pk.jpg.

Our plant is mostly known as the Texas Knotweed, Striped Smartweed or Striped Knotweed. It's POLYGONUM STRIATULUM, in the whole world known only from Texas where, the Flora says, it occurs in "Seasonal moist places, sterile prairies, granitic soils."

Not much information is available about this seldom-noted species. I'm glad to provide what little we have here.

*****

COASTAL INDIGO
Dangling from the dry top edge of a roadcut through a geologically old deposit of mixed limestone cobbles and silt, a wiry stem with pinnately compound leaves bore several small, salmon-pink flowers, as shown at http://www.backyardnature.net/n/14/140907in.jpg.

The pinnately compound leaves immediately suggest the big Bean Family. A closer look showing how they are heavily invested with sharp, pale hairs held against the leaves' surface is at http://www.backyardnature.net/n/14/140907io.jpg.

Even closer, the flowers display the typical Bean Family "papilionaceous" structure -- a conspicuous top petal, two side petals or "wings," and two lower petals fused along their common margin to form a scoop-shaped "keel," and- confirms the Bean Family for us. A flower close-up is at http://www.backyardnature.net/n/14/140907im.jpg.

In that picture, notice how the whitish filaments of this flower's ten stamens unite to form a cylinder around the pistil's long style, except for one stamen that's held apart, visible in our photo. Such 9+1 stamen arrangement is widespread in the Bean Family. Stamens arranged in this manner are said to be "diadelphous."

The flower's upward-jutting top petal, its side petals' or wings' of a much narrower-than-usual width, and the long, straight cylinder formed by the diadelphous stamens reminded me very much of Lindheimer's Indigo, common here in cobblestone fields along the Dry Frio. But Lindheimer's Indigo is more bushy and upright, and the flowers are different colored, even if their structure is similar. For the pleasure of enjoying the "variation on a theme" effect, you might enjoy comparing our above flower picture with a similar close-up of a flower of the Lindheimer's Indigo at http://www.backyardnature.net/n/13/130811ip.jpg.

So, the short story is that this is a different species of "wild indigo" -- another species of the genus Indigofera. It's INDIGOFERA MINIATA, variously known as the Coastal Indigo, Texas Indigo, Western Indigo and Scarlet Pea. Indigo dye, so important to our ancestors, was produced by several species in the genus Indigofera, but our Coastal Indigo is surely too small and spindly for that purpose.

Coastal Indigo occurs from Guatemala all through Mexico, and in the US is fairly common on well-drained sand, loam, clay and caliche in Texas, Oklahoma and southern Kansas, and spottily along the Gulf Coast and throughout Florida. Though I don't often see it in the Dry Frio Valley, the Wildflower.Org website reports it as abundant in open areas of the eastern two thirds of Texas. Coastal Indigo is further said to be relished by deer and grazed by livestock, so maybe that accounts for its uncommonness here, where White-tail and Axis Deer are grossly overpopulated.

The seeds, or beans, of Coastal Indigo are eaten by Bobwhite and Mourning Doves. Among butterfly caterpillars feeding on the leaves are the larval stages of the Gray Hairstreak, Common Dogface, and Reakirts Blue.

*****

TIE VINE, VARIETY #2
A year ago we looked at a certain lilac-flowered morning-glory vine found draped on a bush at the woods edge along the Dry Frio River. Among its names was Tie Vine; it was Ipomoea cordatotriloba, occurring throughout much of the tropical and subtropical Americas, and extending into the US into the southeastern Gulf Coast states and a little beyond. It's on display at http://www.backyardnature.net/n/h/ipomoea2.htm.

This week, in deep shade along the road in an Ashe Juniper stand ,a morning-glory turned up with what seemed to be the Tie Vine's flower, but instead of having three-lobed leaves like those shown on our Tie Vine page, and a very long-hairy calyx, it produced heart-shaped leaves and its calyx was completely hairless. You can see this week's find twining around a juniper branch at http://www.backyardnature.net/n/14/140907ip.jpg.

A peep into the pretty flower's mouth, which is dark, unlike the gardener's purple-flowered morning-glories with their corolla tubes white inside, is shown at http://www.backyardnature.net/n/14/140907ir.jpg.

I'd read that the Tie Vine's leaves can range from deeply three-lobed to heart-shaped with no lobes, so the very different leaf shapes didn't surprise me. What did surprise, however, was the absolutely hairless calyx, shown at http://www.backyardnature.net/n/14/140907iq.jpg.

Hairiness can vary somewhat between individuals of the same species without it having any significance. But this difference between a calyx with many long hairs and a calyx that's completely hairless is extreme, as you can see if you compare the calyx of last year's morning-glory with this year's. On the Internet I looked into the matter.

Now I see that two varieties of Tie Vine formally are recognized. Last year's hairy one was the "typical" one, Ipomoea cordatotriloba var. cordatotriloba, described as occurring mainly in deciduous forest. This week's hairless one is Ipomoea cordatotriloba var. torreyana, described as found mainly in prairies and plains. The junipers in which this week's vine occurred were beside a grassy prairie patch in the upper Dry Frio Valley, in Real County, plus junipers are evergreen, not deciduous trees, so all that works out OK. I read that where the two habitat types meet, often the resulting morning-glory's appearance is intermediate that of the two varieties.

Often when a species is represented by two or more formally recognized varieties, the varieties are geographically separated. It's not unusual in such cases for intermediate forms to occur along boundary lines held in common. Here the two varieties occur in the same geographic location, but in different habitats.

Though in our area Tie Vine is fairly uncommon and offers a welcome splash of color where otherwise there's just greenness, I read that in some rainier parts of the US Deep South it can become a "rampant and aggressive grower that can be troublesome in a garden setting."

*****

HYBRID LANTANA
In the parking lot of Uvalde's fine El Progreso Memorial Library a certain bush forms a dense, knee-high, broadly spreading mound with some of its side branches sprawling onto the pavement, as shown at http://www.backyardnature.net/n/14/140907la.jpg.

Up close you can see the bilaterally symmetrical flowers with their slender, curved tubes arising from stems with two leaves per node (opposite) and which are square in cross section, as shown at http://www.backyardnature.net/n/14/140907lb.jpg.

Gardeners recognize this as a lantana, close to Lantana camara, which grew beside the Red Cabin in the valley where I lived earlier, and is featured at http://www.backyardnature.net/n/w/lantana2.htm.

Lantana camara has produced many cultivars with flowers mostly in the yellow-pink range, the colors often changing as the flowers mature, but some cultivar flowers are pure yellow or orangish. However, cultivars shown on the Internet tend to have their flowers more tightly clustered than those in our picture. Of hundreds of pictures scanned, only one matched our flowers' looser arrangement and color -- one on a University of Florida page listing their plant's name as Hybrid Lantana, LANTANA x HYBRIDUM.

The "x hybridum" species name often is appended to plants whose genes are so hopelessly scrambled by years of hybridization and other genetic tricks that it would be misleading to list the two dominant parent species. It's just "hybridum." It is what you see when you see it.

Though sometimes hybrids give me the creeps with their heavy emphasis on colorful, oversized flowers at the expense of all other traits, I wouldn't mind being classified as Homo x hybridum myself -- of being automatically accepted as "what you see when you see it," and not perceived according to stereotypes or preconceptions.

*****

FEATURED ESSAYS FROM THE PAST:

"Sky Orientation" from the November 18, 2001 Newsletter, at http://www.backyardnature.net/n/p/011118.htm

"Zombie Ants & Smart Dogs" from the August 16, 2009 Newsletter, at http://www.backyardnature.net/n/p/090816.htm

*****

Best wishes to all Newsletter readers,

Jim

All previous Newsletters are archived at http://www.backyardnature.net/n/.