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

July 13, 2014

RED-EARED SLIDERS
In the green, placid waters of the little Leona River coursing through Uvalde's Memorial Park an old tree snag rose from the water just the size and orientation to invite turtles to climb up and bask. You can see three of them doing exactly that at http://www.backyardnature.net/n/14/140615re.jpg.

Whenever I see basking turtles of that general size and shape I figure that they're probably Red-eared Sliders, also called Red-eared Terrapins and Red-eared Turtles, TRACHEMYS SCRIPTA ELEGANS. That's because that species is abundant and very widely distributed. It's so tough and adaptable that it's often sold in pet shops throughout the world and thus has become an invasive species far beyond its native homeland, which is the southern US and northern Mexico. During our Newsletter days we've run into them from Oregon and California to Mississippi, south to the Yucatan.

But, somehow these particular turtles' upper shells, the carapaces, looked a little flatter and more widely flaring around the edges than I'm used to, so maybe this was a similar and more interesting species. Specifically, in our area the Texas River Cooter, Pseudemys texana, also can turn up, and that one, endemic just to Texas, is noted for its flattened carapace thats toothed, or "serrated," at its rear.

In the end I couldn't decide which we had, so off I went to http://www.Texasturtles.org where an offer is made to identify pictures of Texas turtles if they can keep the pictures. Verdict: Red-eared Sliders.

The determination was made by Carl Franklin, no less than the Biological Curator of the Amphibian and Reptile Diversity Research Center at The University of Texas at Arlington. He writes that one good field mark for the Red'eared Slider consists of the horizontally oriented, line-like furrows on that species' carapace. He says that the furrows are so diagnostic that they can even be used to ID fragments from road killed specimens. However, the best field mark, which maybe I'd have seen without my cataracts, is that, as he writes, "The one on the left has red ears ... "

*****

JUMPING SPIDER
While painting a house, a jumping spider came climbing up a drop cloth I had covering a window. Jumping spiders are famous for reciprocating the curiosity shown by humans examining them, so I placed my hand imediately in front of the spider, who instantly jumped onto it, offering the picture shown at http://www.backyardnature.net/n/14/140615js.jpg.

Last November we looked at the Carolina Jumping Spider, Phidippus carolinensis, which I remembered as looking pretty much like this one. You can compare the picture of that one with what's in our current picture at http://www.backyardnature.net/n/a/jumpspid.htm.

Once I compared the pictures it was easy to see that the patterns on the abdomens were a little different, and the spiders' shapes differed, too. So, off this week's pictures went to volunteer identifier Bea in Ontario.

Bea, using BugGuide.Net's "browse-button technique" described here a couple of weeks ago, decided that this time we had what's sometimes called the Tan Jumping Spider, PLATYCRYPTUS UNDATUS. Tan Jumping Spiders are fairly widely distributed across the Eastern States and adjacent Canada, west to Wisconsin and Texas, south through Mexico into Guatemala.

Besides jumping spiders being among the most handsome of spiders, they're also known to have excellent vision -- among the best eyes of all invertebrate animals. Their eight relatively large eyes are arrayed on their front body section, or cephalothorax, in a way helping the spider see all around and judge distances acutely. A shot showing the arrangement of our spider's eyes is at http://www.backyardnature.net/n/14/140615ju.jpg.

Among jumping spiders it's typical that two especially large eyes occupy the front-most position on the cephalothorax, and that a widely spaced pair of much smaller eyes is set fairly far back. A very nice shot showing our spider looking exactly at us -- an instant before jumping onto the camera lens -- is at http://www.backyardnature.net/n/14/140615jt.jpg.

In that picture the two pale, very fuzzy little arm-like items below the face are not legs, but rather "pedipalps," also called palps. They're used to feel and manipulate, plus they bear sensitive chemical detectors and serve as taste and smell organs, supplementing similar tasting and smelling done by the legs.

Jumping spiders are members of the Jumping Spider Family, the Salticidae, the largest of all spider families, embracing about 500 genera and 5000 species -- about 13% of all spider species, and mostly found in the tropics. Instead of building webs for catching prey, jumping spiders range about, often on vertical surfaces like my drop cloth. Right before jumping they anchor a strand of silk to something solid, so if they miss their target they return to their original spot by following or maybe climbing the silk strand.

*****

A FRUIT FLY MIMICKING A JUMPING SPIDER
At the house in the valley where I was painting, a fruit fly hang on a veranda's wire screen. I knew it was a fruit fly because it was small with a yellowish body, blue eyes, dark markings on its otherwise transparent wings, and every few seconds it would curl and flex its wings in a strange way I've only seen fruit flies do, a behavior known as wing-waving. You can see this colorful little fly at http://www.backyardnature.net/n/14/140615ff.jpg.

Actually, the term "fruit fly" is so general and imprecise that it doesn't say much about who the fly actually is. Not only many genera but also several entire fly families are known as fruit flies. The best known fruit flies are of the genus Drosophila, but they're much smaller than the one in our picture, Using the dandy BugGuide.Net website and the picture-matching technique described here awhile back, our little fly was so distinctive that I could figure out its genus, Zonosemata. And since the genus Zonosemata has species that can damage agricultural crops, the USDA provides a well illustrated key to Zonosemata species at http://www.sel.barc.usda.gov/diptera/tephriti/zonosem/ZonosKey.htm.

It's ZONOSEMATA VITTIGERA, with no good common name, though often it's referred to as a tephritid fly, a general name alluding to its membership in the family Tephritidae, one of the two largest families holding species most commonly referred to as fruit flies. Because of their bright colors and bold wing markings, members of the Tephritidae are sometimes called peacock flies.

Zonosemata vittigera is a bit famous, and its wing-waving is part of what it's famous for. That's because the dark lines on its wings, the markings atop its thorax, and its wing-waving all contribute to enabling the species to mimic the territorial display of its jumping spider predators. In other words, jumping spiders prey on fairly defenseless Zonosemata fruit flies, but when the flies wave their wings, to a jumping spider it looks like another jumping spider making threatening displays at them, so the spider retreats.

To see the spider in our fruit fly, look at our picture thinking in terms of the fly's roundish, yellow rear end, or abdomen, as a spider's front body segment, or cephalothorax, and the fly's dark thorax (segment behind head) as the spider's abdomen, with the dark bars on the fly's wings being legs issuing from the spider's cephalothorax. When the fruit fly wing-waves, to the jumping spider it looks as if the enemy spider is signaling its "agonistic territorial display" with its legs a display that can be interpreted into plain English as "This is my territory, so get away!"

Amazingly, it's been proved that the mimicry practiced by Zonosemata flies actually does keep jumping spiders from attacking them. The experiment consisted of transplanting housefly wings onto Zonosemata vittigera, and Zonosemata vittigera wings onto houseflies. Both Zonosemata flies with transplanted house fly wings and house flies with transplanted Zonosemata wings were attacked by jumping spiders, which shows that both the fruit fly's wings and body markings are important in order to deceive the spider.

Zonosemata vittigera mostly occurs in Mexico, from the Isthmus of Tehuantepec northward, extending into the US from Arizona to Oklahoma and Texas.

The only known host plant for Zonosemata vittigera is the Silver-leaf Nightshade, Solanum elaeagnifolium, an abundant roadside weed here. We profile it at http://www.backyardnature.net/n/h/solanum1.htm.

*****

PENNSYLVANIA SMARTWEED
In the bottom of a drainage ditch in Uvalde the weeds were lush and green as they were nowhere else in town, and someof the weeds, about belly high, bore stiff, slender peduncles at their tops tipped with spike-like flowering heads that looked like pale, pink caterpillars standing on their heads. This is seen at http://www.backyardnature.net/n/14/140615pp.jpg.

This plant's general form and presentation of flowers is so distinctive, and the plant-type so commonly encountered, that most fans of wildflowers and weeds instantly recognize it as a kind of smartweed, also known as knotweed, of which maybe 55 species are listed for North America. When I was learning my botany, smartweeds were placed in the genus Polygonum, but since then numerous species known as smartweeds have been exiled to the genus Persicaria, and this is one of them. In fact, in eastern and central North America it's one of the most commonly occurring and easily recognizable smartweed species. It's the Pennsylvania Smartweed, sometimes called Pinkweed, PERSICARIA PENSYLVANICUM.

When you think you have a smartweed but want to confirm it, you need to look for a vegetative feature that serves as a very good field mark for the family to which smartweeds belong, which is the Buckwheat Family, the Polygonaceae. That field mark is the cylindrical sheath or "ocrea" completely surrounding the stem wherever a leaf's petiole attaches to the stem. You can see the Pennsylvania Smartweed's ocrea at http://www.backyardnature.net/n/14/140615pr.jpg.

Some ocreas bear atop their top edges conspicuous hairs, but you can see that Pennsylvania Smartweed's don't, and that's one important field mark for this species. The above picture shows another important distinction of the Pennsylvania Smartweed, which is that its stems are heavily invested with tiny, dark, sticky glands held atop short, stiff hairs -- they're "glandular hairs." Most smartweed species don't have these.

It's interesting that these important diagnostic features are vegetative, not sexual -- not details of flowers or fruits. In most cases it's the other way around. You can see Pennsylvania Smartweed's flower which is, though pretty enough, not much different from flowers of many other smartweed species, at http://www.backyardnature.net/n/14/140615pq.jpg.

One feature seen in that flower that's typical of the entire Buckwheat Family is that the petal-like, colorful parts are neither the petals of a corolla nor the normally green sepals of a calyx, but rather they are simply undifferentiated, look-alike lobes functioning as if they were corolla petals. In such a case the collection of colored, corolla-like parts is referred to as a perianth.

*****

PEPPERWORT
One of the most commonly encountered and easy to recognize spring wildflowers/weeds is the pepperwort with its cylindrical, raceme-type flowering heads held about meagre herbage like little pagodas. You can see the effect with a pepperwort in my abandoned, leafcutter-ant-infested garden in the valley at http://www.backyardnature.net/n/14/140615li.jpg.

From the beginning, these pepperworts struck me as somehow different from the ones I'm used to in gardens and along roads and city sidewalks not only in the US but throughout most of Mexico. The Flora of North America reports that of the 220 or so known pepperwort species -- members of the genus Lepidium -- 42 are found in North America, so there no reason why my garden pepperwort has to be the "usual species." You might enjoy comparing the above picture with one of the "usual species," Lepidium virginicum, a tough, vigorously adaptive species very common in North America coast-to-coast and south through Mexico and Central America, and invasive in much of the rest of the world, at http://www.backyardnature.net/yucatan/lepidium.htm.

For one thing, notice how our garden species' flowers at the top of the racemes are so tiny and densely crammed together. A close-up of the flowers, as well as maturing flat, roundish fruits that on their pedicels look like green spoons with very slender handles and notches at the spoons' tips, is at http://www.backyardnature.net/n/14/140615lj.jpg.

One field mark distinguishing our garden pepperwort from many other pepperwort species is that it's an annual herb, not a biennial or perennia. Another is that our present pepperwort's flowers bear only two stamens, while flowers of some other species bear four. In the above picture, near the top, left of the flowering raceme you can see the very small, much reduced and simple flower -- this one even without petals -- with its two yellow-tipped stamens.

Usually but not always a plant' hairiness is regarded as a poor field mark, since often that feature varies from plant to plant of the same species, and hairs may fall off as plants mature. However, among the pepperworts, hairiness is something important to notice. You can see one of our garden pepperwort's shallowly and broadly toothed leaves with its slender petiole, as well as the stem's manifest hairiness, at http://www.backyardnature.net/n/14/140615lk.jpg.

A closer look, showing that the hairs are stiff, not soft, and that on the stem they tend to bend slightly downward, is shown at http://www.backyardnature.net/n/14/140615lm.jpg.

This distinct kind of hairiness helps us separate our garden pepperwort from the very common species, which is less hairy, and when it bears hairs its hairs are softer and not so stiff.

Our garden pepperwort turns out to be what's often called the Southern Pepperwort, or Southern Peppergrass, LEPIDIUM AUSTRINUM. Unlike the very widely distributed "usual species," Southern Pepperwort is endemic only to Texas, Oklahoma, and arid northeastern Mexico, plus very spottily here and there in some other US states.

In general, pepperworts -- probably more often called peppergrasses though they're a long way from being grasses -- are members of the Mustard Family, the Brassicaceae. That sounds right because one of the first living-off-the-land tricks novice wildflower students learn is how pleasantly peppery the fruits taste when sprinkled onto a salad or nibbled from the hand. They can be easily harvest by pulling a raceme between two fingers. You can see some immature, silicle-type fruits plus some mature seeds with their split pod coverings at http://www.backyardnature.net/n/14/140615ll.jpg.  

*****

PROSTRATE ROSEMARY
In a traffic island in the parking lot of Uvalde's fine public library a dense, woody shrub formed a waist-high mound with branches cascading onto the sidewalk, and the bush was full of small, pale flowers, creating an effect I couldn't remember seeing before. The whole thing is shown at http://www.backyardnature.net/n/14/140615rs.jpg.

Up close, the flowers showed themselves to be typical blossoms of the Mint Family, the Lamiaceae, the main field marks being their strong bilateral symmetry (only one way to cut them down the middle so that mirror images are seen on both sides of the cut), having only two stamens (in other families with similar flowers 5 is more typical), and, down in the bottom of the flowers' throats the ovaries were deeply four-lobed, forming four little green "nutlets" looking tiny green eggs with the slender style arising between them. Two flower are shown at http://www.backyardnature.net/n/14/140615rt.jpg.

The flowers bespoke the Mint Family, but the shrub's leaves were distinctive enough to identify exactly what kind of mint we had, for they were small and slender, leathery, and their margins curled beneath the blades in a way not often seen. A picture with a leaf in the middle showing its rolled under margins is at http://www.backyardnature.net/n/14/140615ru.jpg.

This was a Rosemary plant ROSMARINUS OFFICINALIS, despite Rosemary normally being thought of as a garden herb that stands quite erect, not at all producing long, trailing branches like this plant. But with such flowers and leaves, and its strong Rosemary odor, it couldn't have been anything else. Clearly it was a cultivar with genes so thoroughly scrambled by generations of horticulturalists that almost anything might result. Our plant looks very much like the cultivar 'Prostratus."

Rosemary's Wikipedia page currently lists 21 frequently selling cultivars of Rosmarinus officinalis, so a gardener could create quite an exhibition just by growing different kinds of Rosemary.

Rosemary is a woody shrub originally from the Mediterranean region. The name "Rosemary" derives from the Latin "ros," for dew, and "marinus," for sea, so the Rosemary herb is "Dew of the Sea."

In my own life, Rosemary is especially welcome during the cooler months when a few Rosemary leaves steeped in hot water make a fragrant, wholesome-smelling tea that somehow is soothing and at least feels as if it's doing good things to my innards.

*****

SCUM MYSTERY
It all started when some guests at Phred's left behind a big bag of large, dried Guajillo Chili peppers. Apparently they'd wanted to grind the brittle skins into powder to make their own spicy barbecue sauce. I inherited the peppers, didn't want to make barbecue sauce, so each night I'd soak two or three to soften them up, then the next day add them to my omelets or sautéed creations. But when for a couple of days I skipped the soaking process, leaving out my soaking container. Before long an interesting scum formed atop it, shown at http://www.backyardnature.net/n/14/140615ft.jpg.

Wanting to see how this would develop, I let things continue. The next day the soaking juice's entire surface was white and the scum had developed intricate folding, as seen up close at http://www.backyardnature.net/n/14/140615fu.jpg.

The next day the folds were collapsing and turning dark gray. I guessed that the scum was some kind of fungus and the dark parts were areas of spore production. A close-up of the scum at this stage is shown at http://www.backyardnature.net/n/14/140615fv.jpg.

At this point I wanted to scoop some wrinkled scum onto a finger for examination under high magnification, thinking I'd see wrinkles composed of fungal hyphae sometimes producing spores. But when the wrinkles were touched they fell apart, leaving behind something like dust atop the water, shown at http://www.backyardnature.net/n/14/140615fr.jpg.

So, I looked at the "dust" with the microscope. At first I found nothing, looking for fungal hyphae with a fairly low magnification. However, after using higher and higher power, finally I saw what appears at http://www.backyardnature.net/n/14/140615fs.jpg.

You see see exceedingly small cells at the edge of a drop of pepper-soaking juice. Most cells are more or less egg-shaped, but some are longer, and these must be cells dividing asexually, forming new individuals. I assume that these are yeast cells, and pictures on the Internet of yeast cells of the kind that ferment fruit juices look just like these.

So, yeasts are members of the Fungus Kingdom, and about 1500 yeast species have been described so far. They are unicellular and species size varies greatly, typically measuring 3-4 µm in diameter, or 0.003 to 0.004mm, though some get larger than 40 µm, or 0.04mm.

A good bet is that our yeast is a member of the genus Saccharomyces, which is most commonly involved with fermenting fruit juices. Brewer's yeast or baker's yeast, often used as a B-vitamin food supplement, is a Saccharomyces. Saccharomyces cerevisiae, is used in making wine, bread, and beer. When Saccharomyces species ferment -- presumably what was going on in my pepper juice contain -- they convert carbohydrates to carbon dioxide and alcohols. During my pepper soaking process, many simple carbohydrates must have seeped from the peppers into the water, offering yeast cells just what they needed.

Some yeasts cause diseases, such as the genus Candida, which causes an oral and vaginal infection in humans known as candidiasis. The yeast genus Cryptococcus attacks people whose immune systems are weakened, especially those with HIV/AIDS, causing over 600,000 deaths annually. However our pepper-juice loving Sacchoromyces yeast doesn't seem to attack humans, and I'm glad to cohabit with it, especially knowing that sometimes it forms such prettily folded white scum.

*****

Best wishes to all Newsletter readers,

Jim

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