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

February 17, 2013

DEER PELLETOLOGY
Deer wander around the cabin every night, often leaving their scat, or poop. The other morning two long donations had been dribbled across the gravel driveway, a small part of which is shown with my fingers providing scale at http://www.backyardnature.net/n/13/130217dp.jpg.

Deer scat is produced in pellet form similar to that of rabbit poop, except that rabbit pellets are spherical while those of deer are more oblong. Some trackers say that most deer pellets have a dimple on one end and a point on the other, and that's the case with some but not all the pellets in the picture. These dimples and points are just a small part of what can be noticed about deer scat, in the science we can call deer pelletology.

Why pellets? There are several reasons.

First, deer, along with rabbits, sheep and other pellet-dropping mammals, have much more efficient digestive systems than many other mammals, including humans. Deer are ruminants with four chambered stomachs in which bacteria break down the otherwise indigestible cellulose into nutrients the body can use. Deer guts are about 28 feet long (8.5m), so there is plenty of length along which not only nutrients can be absorbed through intestinal walls but also water. Therefore, what comes out of a deer is a surprisingly small fraction of what goes in, and normally what exits is fairly hard and compact. The drier the forage eaten, the harder the pellets and the more strung-out they tend to be when deposited. The moister the forage, the softer and stickier or even mushy the pellets, and the more clumped the deposit tends to be.

This doesn't explain why deer turds are pellet-shaped. However, any human who doesn't drink enough fluid notices the next morning that what comes out is hard and pellet-like. It seems that dry poop tumbling through long intestines just naturally comes out in pellet form.

There's still the question, though, of why deer pellets should be about the same size of those of rabbits, even though deer are much larger than rabbits. Why don't deer produce baseball-sized pellets?

One explanation is that it's a basic law of Nature that small spheres have larger surface areas per unit volume than larger spheres. If your body wants to extract as many nutrients and as much water from your pellets as possible, these things are more efficiently absorbed through the relatively large surface areas of many small pellets than through the relatively small surface areas of a few large ones.

The average number of pellets in an ordinary deer movement, by the way, is 75. And a study done back in 1940 found that deer defecate on the average 12.6 times a day.

*****

AN ALMOST WHITE BLACKBIRD
The other day my neighbor Fred was in downtown Uvalde south of here when he came upon a small flock of blackbirds on a street, and one of the birds was mottled black and white as shown at http://www.backyardnature.net/n/13/130217bb.jpg.

Fred assumed that the birds were Great-tailed Grackles, which are abundant in town, but the tail and beak of our speckled bird aren't long enough to be that, nor even the smaller Common Grackle. I was unsure who it might be so I sent the picture to my old birding buddy Jarvis in North Carolina who is PHD'd in ornithology. Jarvis suggests that it's a Brewer's Blackbird, pointing out the pale eye, which distinguishes it from a Red-winged Blackbird, and the fact that Brewer's Blackbirds are known to be abundant in our area, in fields, around ranches and along roadsides.

When you see an animal patterned like this bird you think "partial albino." However, when you look into the matter on the Internet you find other options. Most photos similar to ours and posted by people who ought to know their business label such birds as "leucistic."

Leucism is different from albinism in that albinism results from the absence of the pigment melanin, while leucism comes about when all pigments are missing, not just melanin. Thus in species whose colors are produced by a variety of pigments albinos are not entirely white, but rather pale yellow. Leucistic individuals, in contrast, are entirely white or at least their leucistic parts are pure white.

Partial leucism like that shown in Fred's bird produces what is known as a "pied" or "piebald" effect. Piebaldness is especially common among domestic animals -- horses, cows, cats, dogs -- as well as Crows who hang around urban areas. Since the effect occurs mostly among domesticated and semidomesticated animals, it should be no surprise to see a piebald Brewer's Blackbird, since that species has adapted so well to human environments.

Why does piebaldness mostly occur among domesticated or semidomesticated animals? One way to think about it is that around humans piebald individuals are less likely to be noticed by predators than in the wild, so they end up passing their genetic malfunction causing leucism to their offspring.

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MAYFLY NAIAD
Embarking upon this week's safari into the water of the little Dry Frio River below the cabin I placed the tip of a medicine dropper against the fuzzy, algae-encrusted surface of a small, submerged limestone rock and sucked into the dropper's tube an object just large enough to see with the naked eye. When the tiny, slender critter was on a slide beneath the microscope he measured about one millimeter, or 1/32nd of an inch in length. You can see him at http://www.backyardnature.net/n/13/130217ni.jpg.

A close-up of the head area is at http://www.backyardnature.net/n/13/130217nj.jpg.

With the body divided into a head, thorax and abdomen, and with jointed legs, compound eyes at the side of the head, and what looks like complex mouthparts, this had to be the immature stage of an insect, but I didn't know which one. So, off the image went to volunteer insect identifier Bea in Ontario, who soon decided that it must be a freshly hatched Mayfly.

Mayflies undergo simple metamorphosis, so instead of their life cycle being egg > larva > pupa > adult it's egg > nymph > adult. When the nymph is aquatic, as is the mayfly's, the nymph may be referred to by the special term "naiad." Naiads are aquatic nymphs of insects undergoing simple metamorphosis.

Unlike insects with complete metamorphosis where the larva looks very different from the adult -- caterpillars are profoundly different from the butterflies they eventually become -- nymphs upon hatching already display the basic body structure of the adult, except that they're much smaller and lack appendages that only the adult needs, such as wings and functional sexual parts. As nymphs grow they shed their former exoskeletons. The stages of development between their exoskeleton sheddings are referred to as instars. You might hear an entomologist say something like "By the fifth instar, wing buds are appearing." Mayfly naiads molt twenty to thirty times as they develop over a period of a few months up to several years, depending on the species. In contrast, the adult mayfly typically lives for only a few days.

Being so tiny, our mayfly naiad must have just recently hatched, and I regard that as yet another sign of the coming of spring, and for that I am grateful.

By the way, the three "tails" at the end of our mayfly's abdomen are cerci. Cerci often serve as sensory organs, but in some species they might also be used as weapons or copulation aids, or they might simply be vestigial structures.

*****

ROTIFER
In the same drop of water from the Dry Frio River in which the mayfly naiad was captured from the surface of an alga-carpeted, submerged stone, there were much, much smaller -- about 0.2mm in length (0.008 inch) -- very fast-swimming creatures with what looked like forked tails. At first I didn't even try to photograph them because they were too fast to focus on. However, finally one appeared swimming in circles and sometimes he'd slow down, so he's shown at http://www.backyardnature.net/n/13/130217ro.jpg.

This little multicellular animal is something we haven't seen before in the Dry Frio's waters, a kind of rotifer. Rotifers are important because of the sheer biomass they contribute to aquatic ecosystems throughout the world. About 2200 species have been described so far but it's assumed that many more are to be discovered. Experts aren't in agreement on how rotifers should be classified. Their Wikipedia page asigns them phylum status. Phyla constitute the second-highest major category under the kingdom. For example, one phylum of the Animal Kingdom is the Chordate Phylum, holding all animals with a notochord -- basically animals with backbones, such as birds, snakes and humans. So, if rotifers constitute a whole phylum by themselves, there must be an amazing variety of them taking many shapes and forms. And that's the case, for some species swim freely through the water like ours, others crawl along mud surfaces, and others more or less "root" themselves to underwater substrates.

By comparing our photograph with images on the Internet, and by consulting checklists of microorganisms found in Texas, I've decided that probably our little zipping-about rotifer is a member of the genus Euchlanis, quite possibly EUCHLANIS DILATATA, but I can't be sure. I read that Euchlanis dilatata is used at sewage plants to break down solids in the water, and to eat and digest harmful bacteria.

Field marks identifying microorganisms as rotifers include their bilateral as opposed to radial body symmetry, their more or less cylindrical bodies divided into head, trunk and foot, and their hairlike cilia on their heads. The cilia mainly serve to sweep food suspended in the water into their mouths. Their main foods are bacteria, algae, protozoans and all kinds of very small organic particles.

In our picture we have a side view. The "forked tail" at the right is actually a pair of "feet." The blunt end at the left is the head's "corona" on which you can barely make out short, hairlike cilia. Notice that on the head end of the undersurface there's an opening, which is the mouth. Most of the large, brownish area inside the body is the stomach.

The term Rotifer is derived from a Latin word meaning "wheel-bearer," apparently because movement of the cilia on the head gives the impression of a turning wheel.

*****

SWEETGUM FLOWER BUDS EXPANDING
Though Sweetgums are among the most common trees in eastern North America they don't occur naturally this far west. However, there's a small one planted next to the cabin I stay in. It's stunted and half dead because the species isn't adapted for the long, rainless, very hot weather we experience most of the year. Still, now in February flower buds on at least some of its branches are expanding and about to open, and to me this is a welcome sign of spring. You can see some of the Sweetgum's fast-enlarging, twig-tip flower buds at http://www.backyardnature.net/n/13/130217lq.jpg.

In that picture the smaller, brown scales at the buds' bases have enveloped the buds all winter when the buds were much smaller. Now those scales are spreading wide, permitting green, softer, interior scales to enlarge around the buds' expanding contents, the future flowers, stems and leaves. In that picture, notice that below the terminal flower buds there are much smaller buds containing embryonic leaves and stems that so far have expanded very little or none at all.

On our Sweetgum page at http://www.backyardnature.net/n/w/sweetgum.htm a picture shows what the contents of such buds will look like once the flowers and leaves have burst out. The image is at http://www.backyardnature.net/flswtgum.jpg.

That picture shows how pollen-producing male flowers are grouped into several balls at the tip of the expanding material while female flowers cluster into only two or three balls on drooping stems at the base of the flower cluster. Also you can see a few of the Sweetgum's distinctive five-pointed leaves unfurling from the same bud. All this future greenness already exists in our Sweetgum's expanding buds, as can be seen in a picture showing a bud before and after it was cut down the middle to expose its contents at http://www.backyardnature.net/n/13/130217lr.jpg.

In that image most of the bud is filled with the granular, yellow, pollen-producing anthers of the future male flowers, while at the base, at the left of the cluster of male flowers, there's at least one smaller, paler, immature ball of female flowers from which a future fruit may develop. Below the flower balls several thin layers of green vegetative material is visible. The inner layers are cut-across future leaves.

Speaking of leaves, with tweezers I removed the scales of a small leaf bud growing below a terminal bud. Inside the scales were green leaves with their five lobes directed upward, shown at http://www.backyardnature.net/n/13/130217ls.jpg.

What a pleasure having the little Sweetgum tree next to the cabin harbingering so eloquently the coming of spring.

*****

WHITISH LICHEN ON SWEETGUM BARK
The whitish or pale gray bark of the same little Sweetgum tree nowadays producing expanding flower buds is shown at http://www.backyardnature.net/n/13/130217lo.jpg.

Sweetgum bark is described as gray or grayish, so anyone can be forgiven for assuming that the picture actually shows gray Sweetgum bark. However, if you look very closely at just a single flat, finger-wide plate of the trunk's irregularly fissured bark you see what's shown at http://www.backyardnature.net/n/13/130217ln.jpg.

In recent Newsletters featuring this area's lichens we've seen bowl-like structures such as those, recognizing them as apothecia, which are structures producing spores of the fungus component of the lichen -- and of course lichens are composite organisms consisting of a fungus mingled with a species of alga and/or cyanobacterium. An important difference between the apothecia we've looked at earlier and the ones in the picture is that the ones in the picture are much smaller. Apothecia can be the size of a postage stamp or larger, but the ones in the picture are no larger than 1mm across (1/32nd inch) and most are much smaller.

So, our first picture of the little Sweetgum's bark doesn't really show bark, but rather the trunk's encrustation of grayish lichen.

Using the "Dynamic Key" linked to at http://lichenportal.org and referring to pictures on the Internet, it seems that our Sweetgum-bark-encrusting lichen may be LECANORA CHLAROTERA, sometimes known by the English name of Rim Lichen. The species is "subcosmopolitan," meaning that it's found nearly worldwide but missing in some places. It's noted in Africa, Asia, Europe, and North and South America. In the US it seems to occur mainly if not exclusively in the southern half of the country, coast to coast.

Some lichens occur only on rocks, others on the ground and some in other places, but Rim Lichen lives on tree bark, especially "nutrient rich" tree bark. With Sweetgum wood so famously resiny, it's easy to believe that its bark contains enough nutrients to make any bark-loving lichen happy.

One ecological service this little lichen provides is the important one of its algal cells producing oxygen during photosynthesis, in a location -- dead tree bark -- where otherwise little would be going on benefiting the entire ecosystem.

*****

CALENDULA
When my Estonian lady friend Malle arrived here early last October she accidentally brought some flower seeds from Estonia, which we planted. Malle says the plant producing the seeds is much grown in Estonia with its short, cool summers, and its dried flowers are used in medicinal teas. She called the plant producing the seeds Saialill, which her dictionary translated into "Marigold." However, the seeds didn't look at all like Marigold seeds, nor did the plants arising from the seeds.

The plants grew, but not well during our months of ever-shorter days and colder temperatures. By the Winter Solstice they were droopy and had to be washed with detergent water every two or three days to keep down the aphids, which nonetheless kept sucking on them mercilessly.

Now with longer, sunnier days and springy temperatures the plants are beginning to look healthy and the aphids have practically disappeared, even though I no longer spray detergent water on them. This week they flowered, as you can see at http://www.backyardnature.net/n/13/130217ca.jpg.

A pretty close-up showing tiny, reddish-orange disk flowers with their united anthers disgorging heaps of sticky pollen profiled against flaming yellow ray flowers in the background is shown at http://www.backyardnature.net/n/13/130217cc.jpg.

The flowering head of this member of the Composite Family has a bright center, or eye, unlike Marigolds, so on that account alone it's clear that our plant is not closely related to Marigolds. The button-shaped, unopened flower heads with their many involucral bracts in one or two series made me think of the fleabanes, genus Erigeron, though fleabanes aren't supposed to be yellowish. The leaves' manner of extending their blades gradually down their petioles to the stem also reminded me of the fleabanes, as shown at http://www.backyardnature.net/n/13/130217cb.jpg.

Now that the plants are flowering I can figure out who they were: It's CALENDULA OFFICINALIS, in English commonly called Pot-Marigold, even though the species has little to do with real Marigolds. Also it's called Calendula, that name sharing the same root as the word "calendar," the connection being that Calendulas blossom for a long time, "all through the calendar." Calendula is originally from the Mediterranean area, but now grows in gardens and pots worldwide.

On the evolutionary Tree of Life Calendula occupies a twig very near that of the fleabanes, so their similarity to the fleabanes is no coincidence.

Malle was right about the Pot-Marigold's dried flowers being much used in medicinal teas but maybe the plant is most effective against various types of skin inflammation, from infections to bee stings. A study in the 2009 issue of the Indian Journal of Experimental Biology showed that Calendula works by inhibiting the signaling molecules and enzymes that trigger the body's inflammatory response. Calendula also is strongly astringent, so it can be used for minor cuts and burns. A study reported in the 2009 issue of Phytotherapy Research described Calendula as one of the most effective herbs for inhibiting the growth of Campylobacter jejuni, a common bacterium causing severe diarrhea in children. Another study found that Calendula regulates the menstrual cycle and yet another that a Calendula extract killed cancerous melanoma cells and stimulated the immune system's white blood cells.

And Calendula's fresh or dried leaves, though a little bitter, are regarded as tasty additions to certain soups and salads.

What a pretty, tough, and generous little being this Calendula is. This is one annual plant I plan to grow year after year.

*****

JALAPEÑO SEEDLINGS
In this part of the world early February is exactly the time to sow seeds in trays and pots so that later seedlings can be transplanted into the garden. Among the seeds I sowed were those of jalapeño peppers. You can see two seedlings emerging this week at http://www.backyardnature.net/n/13/130217jp.jpg.

In that picture the seedling on the left is emerging as it should, but the one on the right has a problem, a fairly common one with red-pepper seedlings. The problem is that its first two leaves, or cotyledons, are curled up inside the tan-colored seed coat, which should have stayed in the soil as the cotyledons were withdrawn. Now the leaves can't expand as they need to. Usually this happens because the seed coat for some reason dries out and becomes too stiff to yield to the leaves' efforts to withdraw. Sometimes you can help by pulling the seed coat off the imprisoned leaves. Other times while trying to do this you break off the leaves, not helping matters.

Jalapeño seedlings provide a good example of "epigeal germination" -- their cotyledons are raised above the ground and serve as the plants' first two leaves. The other main form of germination is "hypogeal," in which cotyledons remain inside the seed coat below the ground. It happens that I'm sprouting lentil seeds, which are hypogeal. You can see two hypogeal lentil seeds in my hand showing roots growing downward from the seed and sprouts growing upward, with the two cotyledons remaining within each seed coat at http://www.backyardnature.net/n/13/130217jo.jpg.

Cotyledons of hypogeal seeds like the lentil often provide stored energy for the seeds' growing roots and stems during their early part of their growth before the seedlings begin photosynthesizing their own food.

Most gymnosperms and dicots are epigeal like our jalapeños while most monocots are hypogeal. Earlier it was thought that hypogeal seeds were the most evolutionarily advanced, but in fact both germination strategies can be found within the same plant groups, so that assumption can't be made. For example, both germination types occur among the plums, genus Prunus.

*****

FINE-TUNING BEAN SPROUTING
Earlier I reported on my success sprouting large beans bought off the dried-beans shelf at the local supermarket. I've continued experimenting and now have more results to report.

I've tried Pinto, Great Northern and Black-eyed Beans. Pinto gave the best results, Black-eyed the worst, and Great Northern was so-so, but really not so hot. The latter two bean types are more prone to fungal and bacterial contamination, the beans becoming mushy and stinky.

However, I've also tried lentils, and these I find to sprout nearly as easily and contamination free as alfalfa seeds. You can see some sprouted lentils ready to be sandwiched between slabs of hot cornbread or spread as garnish atop a soup at http://www.backyardnature.net/n/13/130217ll.jpg.

Raw, sprouted lentils are described by a nutritional data website as "... very low in Saturated Fat, Cholesterol and Sodium. It is also a good source of Thiamin, Iron, Phosphorus and Copper, and a very good source of Vitamin C, Folate and Manganese." It says that one cup of sprouted lentils provides 19% of the folate, 14% of the iron and 21% of the Vitamin C required of a 2000 calorie diet.

By the way, the website providing this information is very good and easy to use. It's at http://nutritiondata.self.com/.

Nowadays I'm sprouting nothing but lentils, and I'm eating handfuls of them every day with every meal.

*****

FEATURED ESSAYS FROM THE PAST:

"Sunlight, Wind & Karate Dog," from the March 31, 2007 Newsletter, at http://www.backyardnature.net/n/p/070331.htm.

"Sunlight in a Tortoiseshell's Wings," from the June 14, 2009 Newsletter, at http://www.backyardnature.net/n/p/090614.htm.

*****

Best wishes to all Newsletter readers,

Jim

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

Visit Jim's backyard nature site at http://www.backyardnature.net