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

December 16, 2012

WHITE-FOOTED MOUSE
During my hermit years in Mississippi almost daily I had encounters with big-eyed, white-bottomed White-footed Mice, which are quite different from House Mice. The House Mouse, an invasive species from the Old World with small, squinty eyes and of the same mousy color overall, can't survive in woodsy locations such as my old hermit camp, but White-footed Mice are amazingly well adapted and consequently abundant in such places.

So, when at a neighbor's house here a mouse with a white underside turned up stretched out on the sidewalk either dazed or dead from unknown causes, I was curious whether it might be my old Mississippi buddy-species. You can see him at http://www.backyardnature.net/n/12/121216wf.jpg.

The freely available, online Mammals of Texas by Davis & Schmidley at http://www.nsrl.ttu.edu/tmot1/ lists 33 mouse and rat species in the family Heteromyidae just for Texas, and several of those species have white undersides. The book says that White-footed Mice in Texas are most easily confused with Cotton Mice and Deer Mice. However, Cotton Mice are smaller, have a relatively shorter body and brighter color than White-footed Mice, and Deer Mice have tufts of whitish hairs at the bases of their ears and sharply bicolored tails -- white below and dark above. It also says that the White-footed Mouse's tail is about 43% of the body's total length. I measured the tail and body length of our mouse and, by golly, the tail figured out to be exactly 43% of the body's length! The other mice species have tails proportionally of different lengths.

Our White-footed Mouse turned out to be mysteriously dead. His demise won't make much of a dent in the local population, however, since now I know that also in Texas the species is abundant in many habitats, feeding mostly on seeds and especially acorns and pecans, which also are abundant here. Young females mature sexually at the age of 10 or 11 weeks and may bear their first litters at the age of 13 or 14 weeks, so females born in the spring can themselves rear one or two litters before winter sets in. However, White-footed Mice seldom live to be more than 18 months in the wild because so many predators feed on them.

There's a White-footed Mouse in the cabin too smart to fall for any of the peanut-butter-smeared live traps I've devised for him. He's almost become a pet, like the ones back in my hermit camp.

*****

CYCLOPS
While scanning a drop of water from the little Dry Frio River behind the cabin a ghostly creature with a mostly transparent body jerked across the field of vision, as shown at http://www.backyardnature.net/n/12/121216cy.jpg.

This tiny creature, less than 1/25th of an inch long (1mm), was one of over a hundred species of cyclopes, genus Cyclops -- cyclopes is the plural for cyclops -- easily recognizable as a group by the single eyes at the tips of their heads. The eye can be either black or red, and you can see that ours was red eyed. The other red spot on the tail is where mature females bear conspicuous, frankfurter-shaped egg sacs, so maybe that's where this individual's egg sacs either are about to grow, or the eggs have just been shed. Arising near the eye you can see two sizable, ram-horn-like antennae. The rear end divides into the "caudal fork," the purpose of which I can't find explained, though many crustaceans bear more or less forked rear ends.

Cyclopes belong to the Animal Kingdom, the Arthropod Phylum, the Crustacean Subphylum (along with crayfish, lobsters and crabs), the Maxillopod Class (along with barnacles and copepods, all having short bodies and lacking legs), and the Copepod Subclass (the 13,000 copepod species usually being only 1/25th to 1/50th inch long (1-0.5mm) with teardrop-shaped bodies and large antennae).

The more than 400 species of the genus Cyclops occur nearly worldwide, mostly in freshwater but also in brackish. They live along vegetated banks of stagnant and slow-flowing bodies of water, feeding on small fragments of plant material, animals and carrion, and swimming with jerky movements. Sometimes they deal with harsh conditions by forming a cloak of slime. Average lifespan is about 3 months.

Though our little Dry Frio River seems to provide ideal habitat for Cyclopes, I've seen only this one individual. Probably during warmer weather they're much more common.

*****

ANT-MIMICKING BUG
A large, black ant prowled the hairy undersurface of a dried-up leaf on a bush, but there was something funny about that ant. It didn't move right, and somehow it looked odd. You can see what I saw at http://www.backyardnature.net/n/12/121216hm.jpg.

Up close it looked more like an ant than ever, except for two things: it bore immature wings, something I've never seen on an ant, and; more un-anty still, for mouthparts it bore a strawlike proboscis, while ants are equipped with chewing mouthparts. This was no ant, but certainly it was mimicking an ant. Some ants that size can inflict a painful bite, so maybe that's the reason a non-ant bug might want to play the part of an ant.

Volunteer identifier Bea in Ontario figured out that our antlike bug is a real bug -- a member of the True Bug Order the Hemiptera -- and the Broad-headed Bug Family, the Alydidae. She even thinks it's probably the Texas Bow-legged Bug, HYALYMENUS TARSATUS, though positive identification of that little-documented species is so rare that it's hard to be sure.

The Texas Bow-legged Bug occurs here and there throughout most of tropical America, and in the US in Texas. It feeds on beans in pods of certain legume species, but it seems to occur in such small populations that it seldom causes much crop damage.

*****

MINNIE'S STOMACH
The neighbor's cow, Minnie, who leaves impressive and fairly sloppy paddies here and there around the cabin, is an affectionate being who when we eat salad comes right up and nudges us, wanting some. It's impressive how much time she spends grazing grass, and mind-boggling to think of what is actually going on inside her. Basically, Minnie is a walking, mooing ecosystem at the service of microbes in her stomach.

I began thinking like this the other day when I read that in one drop of rumen fluid -- the rumen being a compartment of Minnie's stomach as well as of all "ruminants" such as goats, sheep and deer-- there are more than ten times the number of microbes than people on Earth. That's about a thousand billion microbes per milliliter. The rumen holds up to 95 liters of food and fluid, a liter being a thousand milliliters. At this point in the calculations my mind can no longer deal with all the zeros, not even being able to visualize a million of anything, much less a thousand billion a thousand times. And the rumen is just one of four of Minnie's stomach chambers packed with digestion-assisting microbes.

Recently while Minnie was standing looking at us beseechingly I snapped her picture, which I overlaid with a diagram of her gastrointestinal tract. You can admire this work at http://www.backyardnature.net/n/12/121216mi.jpg.

Minnie swallows a mouthful of grass, which then passes through the esophagus into her spacious rumen, her stomach's first chamber.

The rumen is a fermentation factory where cellulose, fiber and carbohydrates are broken down into compounds known as "volatile fatty acids." Also in the rumen microbes synthesize amino acids from non-protein nitrogenous sources. Food normally goes back and forth between the rumen and Minnie's mouth. When Minnie wants to re-chew some food that hasn't yet digested well in her rumen she regurgitates it, then stands around looking nonchalant while "chewing her cud," then when she's finished chewing, sends her food back to the rumen.

In the picture you can see the entire route her food might take in the inset at the bottom right. Following that diagram's arrows you can see that the next stop for her food after the rumen is the reticulum. Actually the reticulum is an optional stop. It's reserved for things swallowed that are very hard or impossible to digest, like scraps of metal. In fact, sometimes the reticulum is known as the "hardware stomach." On many ranches it's standard procedure to feed a commercially produced "cow magnet" to each calf at branding time. The magnet settles in the rumen or reticulum and remains there for the life of the animal collecting scraps of metal that otherwise might work into the stomach's many folds and perforate the stomach wall, seriously hurting or killing the cow. You can see a cow magnet and read about them at http://en.wikipedia.org/wiki/Cow_magnet.  

The food's next stop is the omasum, which is where water and some nutrients are absorbed from the now fairly well digested food. The omasum's lining is folded like the pages of book to provide a large surface area for absorption.

From the omasum food passes into the abomasum, which is like the human stomach in that it secretes protein- and starch-digesting enzymes to further digest whatever food that hasn't been digested so far. Sometimes the abomasum is known as the "true stomach". The abomasum is shown in our inset but not on Minnie's side because if we were really looking at Minnie's stomach from the side we're on, it would be entirely hidden by the sprawling rumen.

From the abomasum food passes into the small intestine, which occupies much more space than shown in our overlay. The caecum shown on our overlay is considered to be the beginning of the large intestine. It serves as a storage organ that permits bacteria and other microbes time to even further digest whatever cellulose that may have made it that far undigested.

And, from the large intestine what once was food now passes out of Minnie, onto the ground around our cabin.

*****

GALLS ON LIVE OAKS
Branches of our Texas Live Oaks often bear golfball-sized galls like the one shown at http://www.backyardnature.net/n/12/121216ga.jpg.

These galls are conspicuous and well known in Texas, western Louisiana and parts of arid northern Mexico where live oaks occur, and they appear only on live oaks. We've seen galls of similar size, shape and position on tree limbs elsewhere, but they all looked a little different.

The gall, known well enough to bear the common name of Mealy Oak Gall, is caused by a ¼-inch long cynipid wasp called Disholcaspis cinerosa. Interestingly, D. cinerosa produces two generations annually -- an asexual one and a sexual one -- each producing a distinctively different gall type. Our picture's gall is the late summer and early fall type. The spring-type galls are smaller, resembling kernels of wheat in size and shape.

In December and January adult wasps emerge from these fall-type galls by chewing escape holes in the gall walls. All wasps emerging at this time are asexual females who then lay eggs in the terminals of new live-oak leaf shoots causing the spring-type galls. The generation of wasp emerging from the spring-type galls will consist of both males and females, and they'll be about 1/3 the size of the earlier asexual generation.

Abandoned Mealy Oak Galls provide homes to many beneficial insects, but homeowners who see their lawn trees bearing them generally want them off. They seldom do much damage to healthy trees.

A well illustrated document in PDF format discussing Mealy Oak Galls in detail and addressing their damage to trees is provided by the Texas Agricultural Extension Service for free at the Mealy Oak Gall link at http://nueces.agrilife.org/publications/trees-insects-and-problems/.

*****

CHINESE TALLOW TREES FRUITING
At http://www.backyardnature.net/n/w/triadica.htm we look at the invasive Chinese Tallow trees that grow thickly along the banks of the little Dry Frio River behind the cabin, usurping space where otherwise native Sycamores would grow. Now those trees are mostly leafless but many are heavy with clusters of white seeds, inspiring one of the tree's names, Popcorn Tree. You can see a fruiting branch, and a male Cardinal answering the question of whether birds feed on the fruits, at http://www.backyardnature.net/n/12/121216tc.jpg.

A close-up of some seed clusters is at http://www.backyardnature.net/n/12/121216ta.jpg.

You know that those are seeds and not fruits if you've seen the three-lobed capsular fruits that preceded them, and which appear atop our Tallow Tree page. The thin fruit walls fall from the tree leaving the white seeds. A coating of white, waxy substance on the seeds gives the seeds their color. The wax is fairly thick, as shown at http://www.backyardnature.net/n/12/121216tb.jpg.

On the Internet many pages speak of the traditional use of Tallow Tree wax for making candles, coating paper for water resistance, etc. Our trees' seeds seemed to be covered with ample wax so I decided to melt some wax off and see what it looked like. First I tried placing a handful of seeds into a saucer, which I placed inside a closed skillet with a fire beneath it, thinking the heat would cause the white wax to melt into the saucer. The seeds got hot enough that some of them popped like popcorn, but no wax pooled in the saucer. Then I put the seeds into boiling water. A mere film of soapiness eventually spread across the water's surface, but the white "wax" on the seeds stayed in place.

In an online paper at the Purdue University website I read that "Tallow is separated by placing the seed in hot water, thereby melting the tallow which floats on the surface, or by melting tallow with steam and collecting it when it drops off. Solvent extraction of the tallow from the seed is also used, tallow still adhering to the seed being removed by an alkali treatment."

I must be doing something wrong. But that's my experience with it.

*****

CHINABERRIES IN FRUIT
Chinaberry trees, MELIA AZEDARACH, are native to Asia but in North America they were planted as ornamental trees as early as 1830, have escaped and now grow wild from coast to coast in the southern US. Here I don't find Chinaberries growing wild but many people plant them as shade trees that produce masses of pretty, purple flowers and, as they are now, abundant, white, marble-sized fruits. You can see that even the branches of leafless Chinaberry trees in fruit are pretty against a blue sky, at http://www.backyardnature.net/n/12/121216cb.jpg.

Summer's flowering branches are so attractive that in Mexico people make bouquets of them. A picture of such a bouquet and a nice story that goes with it are at http://www.backyardnature.net/q/melia.htm.

I've seen Chinaberry's large panicles of flowers much visited by many pollinators, and also birds eating the fruits, though not with the gusto with which they might go after cherries or even hackberries. You can see a couple of House Finches foraging in the Chinaberry behind the cabin at http://www.backyardnature.net/n/12/121216ca.jpg.

A USDA Forest Service webpage focusing on Chinaberries points to conflicting information in currently available scientific literature about how many seeds occur in each fruit. Therefore, in the service of science I have just stepped outside my door, collected ten fruits from various low-hanging branches and do hereby report that all ten fruits each contained a single hard, stone-like seed. That makes the fruits drupes. Some papers report the fruits bearing up to six seeds, causing the fruits to be berries.

Our fruits, after a hard freeze earlier this week, are turning brown and soft, and smelly, a bit like rancid butter -- the butyric acid smell -- and maybe a little fermented. In fact, reports from Florida say that songbirds may eat so many fermenting Chinaberry fruits that the birds become intoxicated.

*****

BEEBALM SKELETONS
Here and there in the Big Bluestem Grass prairie next to the cabin you see house-size patches of brown, dried-out, thickly occurring, bleached skeletons of a certain wildflower. On a recent foggy morning when the skeletons and the fog created a certain somber but pretty mood I photographed what's shown at http://www.backyardnature.net/n/12/121216bb.jpg.

These are three fruiting heads, each head consisting of many calyxes from long-vanished flowers packed closely within a bowl-like receptacle composed of modified leaves called bracts, with the plant's stem passing through the center of the lower heads. This looks very much like the basic flowering structure of members of the Composite or Sunflower Family, except that in that family you don't see stems passing through flower-head centers. If you're familiar with many wildflowers and garden herbs, probably you're guessing that this is a member of the Mint Family, which it is. Several kinds of mint have their stems passing through the center of flower clusters. A cross section of one of this plant's flower heads is at http://www.backyardnature.net/n/12/121216bc.jpg.

Even this looks like something from the Composite Family, but notice that there's no achene-type fruit below these slender, curvy calyxes, for ovaries in the Mint Family are superior -- arising above the calyx -- not inferior, arising below the calyx, as among the composites.

Usually it's hard to identify non-flowering mints to species level, but this one bore such distinctive fruiting heads, bracts beneath the flower clusters, and calyxes that I gave it a try. It keys out to be the Lemon Beebalm, MONARDA CITRIODORA. Closely related, very similar species exist, but some field marks indicating that this is M. clinopodioides include:

Lemon Beebalm is endemic to Texas, Louisiana, Oklahoma and a bit of Kansas. Its purple/pink flowers are showy and when they appear in May and June our house-size colonies of them should present a bee-buzzed spectacle to behold.

*****

FROSTWEED'S WINGS OF ICE
Back in September we looked at the waist-high composite wildflower locally called Frostweed, which grows in dense stands in the woods along the river. You can see our Frostweed page at http://www.backyardnature.net/n/h/frostwee.htm.

Back East I called the plant Wingstem, so I asked why it was called Frostweed here. I was told that on the morning of winter's first good freeze conspicuous white "wings" of ice emerge from the stem, something very pretty to see. This Tuesday, December 11th, we had our first freeze, with a dawn temperature of 27°F (-3°C). As soon as the sun was up I visited the nearest colony of Frostweed, where well before our freeze the plants had turned brown and dry. You can see the base of one Frostweed stem at http://www.backyardnature.net/n/12/121216fr.jpg.

A close-up of another plant's ice wings bursting from a stem can be seen at http://www.backyardnature.net/n/12/121216fs.jpg.

Very few other plants produce such wings of ice. I assume that Frostweed has this special feature because, as we saw in September, its stems naturally bear green, herbaceous "wings" along their lengths. One assumes that either beneath the vertical wings themselves or between them the stem is weaker than elsewhere. When the stem freezes, water inside it changes to ice, and since ice takes up more room than water, pressure builds up inside the stem, until finally the stem ruptures and ice escapes through the thin fractures lines.

Dr. James Carter at Illinois State University provides an interesting web page discussing the phenomenon, and provides pictures of long, twisting and curling ice ribbons extruding from a variety of situations at http://my.ilstu.edu/~jrcarter/ice/diurnal/extrude/.

*****

FEATURED ESSAYS FROM THE PAST:

"What the Orchids Teach," from the October 28, 2001 Newsletter, at http://www.backyardnature.net/n/p/011028.htm

"What Pumpkin Seeds Teach," from the February 4, 2008 Newsletter, at http://www.backyardnature.net/n/p/080204.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