March 1, 2019
*****
GROPING TOWARD A CATERPILLAR ID
Two years ago several very spiny, black caterpillars turned up feeding on the Cecropia trees in the deep pit next to the hut I live in. You can see them at https://www.backyardnature.net/mexnat/hyalopho.htm
Neither volunteer identifier Bea in Ontario nor I could figure out what they were. Since I'd heard of Cecropia Moths, of the silkmoth group, and Cecropia Moth caterpillars were spiny, I decided to park our pictures of the unknown black caterpillars on the Internet, calling them silkmoths. I hoped that someday an expert might see the pictures and help us out.
Last week silkmoth expert Bill Oehlke wrote saying that the caterpillars didn't look like silkmoth caterpillars at all and, in fact, probably were butterfly caterpillars instead of moth ones.
So, back to Bea, with that new information. But, still, we just can't figure them out. Bea says that probably our caterpillars are member of the Brushfoot Butterfly Family, the Nymphalidae, which is enormous. It's like saying a plant is a grass.
Still, that was something, and when I did an image search on the keywords "Nymphalidae caterpillars cecropia," a page at the ButterfliesOfCuba.com website turned up showing caterpillars very similar to ours feeding on Cecropia leaves. That was Colobura dirce, the Mosaic butterfly, and that species has been observed in the Yucatan.
However, Bea is doubtful: "The host plant matches and the black caterpillar with yellow spines matches, but the "antlers" are not the same as yours. Yours have short black ones, while Colobura have long white ones with a black tip."
Well, it's true. Close, but no cigar, as Bea likes to say.
Anyway, now I'm filing that page under the name "aff. Colobura dirce," the "aff." for "affinity," which is an accepted formal way of saying that we know it's probably not Colobura dirce but maybe it's close, and won't you please help us figure out what it really is?...
This story is presented in the spirit of showing that in much of the world many organisms still aren't well understood, or understood at all. There's still plenty of pioneering work to be done, and often it must begin with sloppy, even embarrassing, best-guessing.
*****
JOINT-VETCH
At the weedy edge of the dirt trail leading into the rancho a ferny-leafed, densely stiff-hairy plant with small, yellow flowers caught my eye, shown at https://www.backyardnature.net/n/19/190301ae.jpg
Even at a distance the pinnately compound leaves with many leaflets suggested the huge Bean Family, the Fabacea, and the plant bore legume-type fruits confirming Bean Family membership, as seen at https://www.backyardnature.net/n/19/190301af.jpg
The flowers when looked at closely proved to have the basic bean-flower structure -- a large top petal, two side petals, and two lower petals with their common margins fused to form a scoop-like bottom -- as shown at https://www.backyardnature.net/n/19/190301ag.jpg
You can see how the big top petal curves upward above the others, and also how very stiff-hairy, or "hispid," the calyx is at https://www.backyardnature.net/n/19/190301ah.jpg
Up north a common group of weeds or wildflowers often known as tick trefoils or stick-tights, genus Desmodium, produces such segmented fruits as shown above, but leaves of species in that genus usually develop only three leaflets. When you see tick-trefoil fruits on a plant with ferny leaves, the first other kind of plant to come to mind should be the joint-vetches, genus Aeschynomene. We've noted a joint-vetch species in the Yucatan before, Aeschynomene fascicularis, shown at https://www.backyardnature.net/yucatan/aeschyno.htm
However, Aeschynomene fascicularis isn't as hispid as this species and has a "softer," less wiry feeling to it. Here we have another joint-vetch species. It's AESCHYNOMENE AMERICANA, actually much more widely distributed than our first one. Aeschynomene americana occurs throughout the tropical and subtropical Americas, plus it's become invasive in many other hot and warm countries. Even in the Americas mostly is seen as a weed not only of roadsides but also in agricultural fields and pastures.
It's a good weed, however, making such good forage for livestock that "improved" varieties have been developed for planting. Plus, like most members of the Bean Family, its root mycorrhiza convert atmospheric nitrogen to forms needed for plant growth, so it fertilizes the soil just by being there.
*****
SIGNALGRASS, YUCATAN STYLE
We first ran into Signalgrass, Urochloa fusca, up in Texas. You can see what some healthy specimens looks like at the base of a corrugated tin wall at https://www.backyardnature.net/n/h/urochloa.htm
This week when I ran into a similar looking grass entangled with many other weedy species along a road, I didn't realize that it was the same species. It turns out that the species is very widely distributed -- throughout the tropical and subtropical Americas, plus it's established in Australia -- and as you might expect of such a broadly distributed species, some of its features vary from region to region, especially with regard to its hairiness and spikelet size.
In fact, I've had a hard time convincing myself that our local roadside grass is just another form of Urochloa fusca. I've settled on the ID mostly by the process of eliminating other possibilities, and that's never encouraging to an identifier.
Whatever the case, below are all the field marks on our local grass I can photograph, and if anyone has a better ID for it I'd like to hear from them.
The rather lanky plant with its flowering head occupying the picture's top right corner is shown at https://www.backyardnature.net/n/19/190301ur.jpg
Notice that at the grass's bottom smaller shoots are emerging. Within the flowering head, a single row of spikelets is arranged along one side of a narrow rachilla heavily beset with long, sharp hairs, as seen at https://www.backyardnature.net/n/19/190301us.jpg
A side view showing how the spikelets line up with one another, and that the bases of many hairs are swollen, is seen at https://www.backyardnature.net/n/19/190301ut.jpg
Our spikelets are a little larger than described in the literature I've seen, as seen against a ruler's millimeter marks at https://www.backyardnature.net/n/19/190301uu.jpg
While leaf blade surfaces themselves are not so hairy, their sheathes surrounding the stems below them are densely so, as seen in a picture also showing the ligule at a blade's base, at https://www.backyardnature.net/n/19/190301uv.jpg
This grass's lower stems tend to run along the ground before arching upward, as indicated at https://www.backyardnature.net/n/19/190301uw.jpg
Certain nodes on the stem's ground-running part issue adventitious roots like those shown at https://www.backyardnature.net/n/19/190301ux.jpg
In Mexico Urochloa fusca is mostly a weedy grass, though when it occurs in pastures livestock gladly eat it. Sometimes it's even cultivated as a forage crop.
*****
ROUGH-LEAFED PEPPER'S PEPPERCORNS
Last October 4th when I was camping in Palenque National Park in Mexico's southernmost state of Chiapas, at a forest edge I came upon a small tree often seen throughout southern Mexico living in shadowy forest understory. It was the Rough-leafed Pepper whose interesting leaves and spikes of tiny, much simplified flowers are nicely shown on our page for the species at https://www.backyardnature.net/yucatan/piper-am.htm
Rough-leafed Pepper, Piper amalago, belongs to the same genus as the Asian Piper nigrum, the dried fruits of which become the peppercorns that are ground up to make black pepper, of salt-and-pepper fame. The Chiapas plant last October bore fruiting heads loaded with future peppercorns, as can be seen at https://www.backyardnature.net/n/19/190301pi.jpg
A close-up of the immature fruits/future peppercorns is seen at https://www.backyardnature.net/n/19/190301pj.jpg
In that picture, each tiny, green, egg-shaped item topped with a little black tuft is a maturing ovary, a future peppercorn. The black items are the shriveled-up remains of the ovary's stigma, that part on which pollen grains land, bearing male sex germs.
These maturing ovaries are too young to dry and grind for use as fresh black pepper, but later they will be, and the pungent pepper produced is just about as good as that provided by the closely related Asian Piper nigrum. For use as pepper condiment, the fruits should be collected a little before reaching complete maturity, because at that point they soften and lose their pungency.
Several traditional medicinal uses are listed for the species. In 2016 M. Mullally and others published a paper in the Journal of Ethnopharmacology (Jun 5, 185:147-54) inspired by reports of Piper amalago being used by Maya Q'eqchi' healers for the treatment of susto. The Spanish word susto translates to "fear," but the condition is more complex than that, and is believed in by many of the Yucatan's Maya, including some of my friends. The researchers referred to susto as "a culture-bound syndrome" that may be a manifestation of anxiety. Therefore, they wanted to know if doses of Piper amalago might reduce anxiety levels.
Rats were fed low doses of ethanolic extracts from Piper amalago leaves. The researchers observed "significant anxiolytic activity in all behavioral tests" (they became less anxious), and even identified a kind of molecule in the extract that was structurally similar to a molecule known to affect anxiety levels.
They concluded that Maya Q'eqchi' healers may be right to treat their susto patients with Piper amalago.
*****
A PANDA'S STORY, & MINE
Visitors left me some copies of The Economist they'd brought from Oregon. The February 2nd, 2019 edition had a section on Panda evolution.
Pandas have a gene called Tas1r1 responsible for the taste sensation called "umami," which detects glutamic acid, a common component of animal flesh. Pandas eat only bamboo, yet basically they are bears, so a good guess is that Panda ancestors were flesh eaters, with more "umami" tasting ability than modern bamboo-eating ones. Wei Fuwen, a zoologist at Beijing's Institute of Zoology, got the idea of testing for the gene enabling the "umami" taste sensation in fossil jaws of Panda ancestors living millions of years ago. He found that evolutionary pressures selecting for the gene in primitive Pandas was much stronger than in modern strictly-bamboo-eating Pandas, who don't need it. Probably early humans competing with Pandas for edible flesh drove modern Pandas into the bamboo thickets, where they found refuge -- from us, for awhile -- and survived by eating only bamboo.
Being reminded that even our tastes are biochemical phenomena enabled by instructions encoded in our genes, I got that old familiar twinge that comes of this: The recognition that we living organisms are basically robots whose behaviors and predispositions are nearly entirely controlled by chance events in our personal histories, and our genes conducting a vast symphony of chemical reactions.
And yet, I do believe that a few thinking, feeling beings are capable of transcending the dictatorships of their personal histories and genetic makeups, by means of consciously applied mentality. Consciously applied mentality in an effort to attain a higher level of understanding, feeling, and behavior, it seems to me, corresponds to one's spiritual quest. The mental quest IS spirituality.
When I fall into this mode of thinking, normally my reflections lead to the brain itself. To begin with, it's helpful to remember that the human brain comprises two parts, or hemispheres, serving different purposes. The left side is logical, practical, fact-oriented and verbal while the right hemisphere deals with feelings, beliefs, symbols, "the big picture," and is basically nonverbal.
Pioneering neuroscientist Michael Gazzaniga refers to the verbal left hemisphere as "the interpreter," saying that it "... constantly establishes a running narrative of our actions, emotions, thoughts, and dreams. It is the glue that keeps our story unified and creates our sense of being a coherent, rational agent. It brings to our bag of individual instincts the illusion that we are something other than what we are."
This quotation mentions "our story." Our story is a brain-generated narrative that tells us who and what we are. The idea I've been toying with this week is that, according to my life experience and of what I've read of certain others, we can edit our stories, expand on them, or even reject them and replace them with others more appealing. Regularly changing one's story as new information and insights are developed is a form of evolution. Also, this kind of story management may be a human's most powerful tool for attaining higher levels of spirituality.
So, that's how it goes when someone leaves a magazine from the outside world. You start with a Panda, learn about that Panda, begin caring about that Panda, and then you find that the Panda has a story, which reminds you that you do, too, and that stories can be, and sometimes must be, changed.
*****
Best wishes to all Newsletter readers,
Jim
All previous Newsletters are archived at https://www.backyardnature.net/n/.
