June 1, 2014
CLOUDBURST BRINGS OUT TOADS
For months I've been speaking of our very severe drought. This Monday, on Memorial Day, we had a cloudburst unlike any I've seen since being here. For several hours nobody in the valley came or went because deep water rushed across all our "low-water crossings." Neighbor Phred says we got six inches (15cm), while Uvalde received eight.
The next day, toads were calling, and along the road I caught the one shown at http://www.backyardnature.net/n/14/140601td.jpg.
That picture, with my thumb for scale, shows one good field mark for the species, which is that it's very small. Another striking feature is that when captured the toad closed his eyes and curved his body so that his soft belly was well protected. He looked like he was sleeping, but the first chance he got he flashed open his eyes and gave a mighty jump.
Last June we saw this same species but that one got away before we could document its most important field marks. Still, we got the good general shot shown at http://www.backyardnature.net/n/a/bufopunc.htm.
In our area we have Green, Texas, Coastal-Plain and Red-spotted Toads. This is the Red-spotted one, the red spots not being conspicuous on the individuals I've seen. Some of the very small warts do turn reddish, as seen looking down on our toad's head at http://www.backyardnature.net/n/14/140601te.jpg.
There you can see another important field mark for the Red-spotted Toad, which is that behind the bulging eyes the tumor-like mounds -- the parotoid glands -- are more or less round in shape. Parotoid glands in most toad species are longer, somewhat triangular or shaped like kidney beans, plus they're larger relative to the eye size. Parotoid glands are "poison glands," secreting neurotoxins -- toxins that affect animal nervous systems. The toxin produced in toad parotoid glands works mainly on the heart in a way similar to that of digitalis. In Hawaii a child died after eating a toad killed by his father in a sugarcane field. Most dogs and cats leave toads alone but those who chomp down on certain species can be poisoned, even die.
Another important field mark of the Red-spotted Toad deals with the slender lines of warts coming together at right angles at the bulging eyes' bases. These "cranial crests" differ from species to species. The Red-spotted Toad's cranial crests are distinguished from those of other toads by being very weakly developed or absent. You might like to compare the above picture with a similarly positioned picture of the American Toad at http://www.backyardnature.net/n/12/120812td.jpg.
Yet another similar picture, showing the very different cranial crests of the Coastal Plain Toad, is at http://www.backyardnature.net/n/12/120916gd.jpg.
Without paying attention to parotoid glands and cranial crests, it can be hard to differentiate the various toad species.
EMERGENCE OF BIG-BOTTOMED ANTS
Early Tuesday morning after the big rain on Memorial Day Monday thousands of very large, amber-colored flying ants turned up dead and dying on the community's gravel road, below a streetlight kept on all night. You can see one picked up as it staggered across the gravel at http://www.backyardnature.net/n/14/140601bb.jpg.
A view of a dead one from below is shown at http://www.backyardnature.net/n/14/140601bg.jpg.
In 2007 in the central Mexican state of Querétaro we saw the same thing, similarly occurring on the day after the first big rain of what normally is the rainy season. You might enjoy reviewing the page describing that outbreak, and brings up the matter than in some places the arrival of these big ants is highly anticipated because they are eaten with relish, and are thought to have aphrodisiacal properties. The page is at http://www.backyardnature.net/q/culonas.htm.
In Querétaro we learned that the big, flying ants were male leafcutting ants. The species seen there were Atta mexicana, so the species we're seeing here in southwestern Texas must be Atta texana, the only leafcutting ant species occurring here. These winged males, called drones or "male alates," are very much larger than the wingless, sterile workers normally seen carrying cut-out shreds of leaves as they march in long lines between their vast underground nests and whatever plant they happen to be defoliating. Last summer they destroyed my beet and turnip crops.
Once a leafcutting ant colony grows to a certain stage, newly hatched queens fly off followed by clouds of males. Once the time for sex has passed, whether the males had luck with the queen or not, the males die. The story of all those dead ants on the community's road, then, whas that on Memorial Day night, at least one queen had left a leafcutter nest followed by many males, and now the males were dead or dying, probably drawn there by the streetlight.
As I surveyed the males' dying field, a wingless ant even larger than they emerged from grass along the road, its head and scissor-like mandibles proportionately much larger than those of the males'. Its shown at http://www.backyardnature.net/n/14/140601bc.jpg.
Though structurally it was similar to the male leafcutters, my first thought was that it was some kind of gigantic carnivorous ant about to feed on the dead and dying male leafcutters on the road. You can see how large this big, wingless ant was on my hand at http://www.backyardnature.net/n/14/140601be.jpg.
In that shot you can clearly see wing stumps, so apparently that ant also recently had flown into the area. A close-up of this big one's head is at http://www.backyardnature.net/n/14/140601bd.jpg.
I watched as a second big, wingless ant entered the dying field headed toward a male who seemed more alive than most of the rest. I thought I might see a fight, but instead I saw what's shown at http://www.backyardnature.net/n/14/140601bf.jpg.
Several times the male climbed atop the big, black ant and made half-hearted gestures suggesting the sexual act. Though the big ant appeared to be receptive to the idea, no sex took place, if only because all the males in this dying field were too weak or exhausted to perform.
Apparently the big, black, wingless ant was a queen. Numerous wings were lying loose on the road, so maybe there were more queens than the two I saw, and they'd landed there, lost their wings, mated, and now were off somewhere digging their own nests.
The next morning all hints of this drama were missing from the road.
FEMALE GOLDEN-FRONTED WOODPECKER DEFENDING TERRITORY
Each morning on most days in March and April both male and female of a pair of Golden-fronted Woodpeckers took turns attacking their own images in windows at my neighbor Phred's house. They were programmed to defend their territories from other woodpeckers of their species, and their reflections in the windows triggered their attacks. The window banging stopped during most of May, but this week they started up again, and I wonder if the return of rain has anything to do with it. You can see Phred's picture of the female on the balcony guardrail beside the couple's favorite attacking window at http://www.backyardnature.net/n/14/140601wp.jpg.
My picture showing the female attacking her own reflection is at http://www.backyardnature.net/n/14/140601wq.jpg.
It was a little surprising to see a female so actively defending territory, because in most songbird species that's the male's chore. Female Cardinals sometimes do the same thing, though, and female aggression in Golden-fronteds is well documented. In Michael Husak's study "Seasonal variation in Territorial Behavior of Golden-fronted Woodpeckers in West-Central Texas," in the March, 2000 edition of the The Southwestern Naturalist, I read:
"Intrasexual aggression was regularly observed between non-mated individuals, including males instigating attacks upon intruding females and females instigating attacks upon intruding males."
Golden-fronted Woodpeckers occur from Nicaragua north through Mexico to the brushlands of Texas and Oklahoma. They look a lot like eastern North America's common Red-bellied Woodpecker, except that the Golden-fronted male displays less color on the head. In the Yucatan this was one of our most commonly encountered birds. We show them pecking at anonas and papayas at http://www.backyardnature.net/yucatan/wp-g-f.htm.
On that page you might notice that Yucatan birds have red on their heads, not yellow. That's because Golden-fronted Woodpeckers are represented by four subspecies that differ in size, amount of barring on the tail, and the color of the nape, nasal tufts, and belly. You can see that the nape of our Texas birds -- and on Golden-fronteds in most of Mexico as well -- is yellow to orange, while it's red on Yucatan birds, and orange farther south. The four forms were formerly considered different species. The Gila Woodpecker mostly of northwestern Mexico shows a different combination, and sometimes has been lumped with the Golden-fronted species. My own personal feeling is that all these variations probably would be best treated as one species, along with the East's Red-bellied Woodpecker.
Memorial Day's first good rain of the year may also have been behind the appearance of a 1¾-inch long (44mm) beetle, dead, on my neighbor Phred's car two mornings later. You can see it at http://www.backyardnature.net/n/14/140601bt.jpg.
The long antennae and general shape quickly orient us toward the Longhorned Beetle Family, the Cerambycidae, but over 35,000 species have been described for that worldwide family, so the challenge becomes figuring out which longhorned beetle we have A view of the underside is provided at http://www.backyardnature.net/n/14/140601bs.jpg.
Volunteer identifier Bea in Ontario narrowed the possibilities to two very similar species, both having been documented in Uvalde County. They're Mallodon dasystomus, often known as the Hardwood Stump Borer, and Mallodon melanopus, usually listed as the Liveoak Stump Borer.
Since maybe 90% of our hardwood trees are liveoaks, I figured we'd have the Liveoak Stump Borer, but Bea and I both, after comparing our individual with lots of pictures on the Internet, think our dead beetle is the Hardwood Stump Borer, MALLODON DASYSTOMUS. Mainly we're looking at ornamentation on the spiny-margined part behind the head, the pronotum, and the way the pronotum's rear part flares out less in the Hardwood species than the Liveoak one. A close-up of our beetle's pronotum is at http://www.backyardnature.net/n/14/140601br.jpg.
Grub larvae of Longhorned Beetles eat various plant parts, depending on the species, and the plant hosts range from healthy individuals to dead, decomposing ones. Just the name "Hardwood Stump Borer" suggests that grubs of our species spend their time tunneling through dead hardwood trees. It's known that grubs of the Liveoak one burrow through liveoak roots, forming a sort of root gall.
In the November, 2012 issue of the Journal of Insect Behavior, Matthew Paschen and others published a study of the Hardwood Stump Borer in which female beetles of the species were described as displaying a calling behavior while lowering their heads and raising their abdomens with their egg-laying ovipositors extended. Matthew Paschen also reports that while calling some females evert a membranous, cylindrical fluid-filled sac from their ovipositors, a maneuver probably involved in the production of and/or release of a male-attracting pheromone. Our dead beetle's rear end displays what might be the mentioned cylindrical sac, as shown at http://www.backyardnature.net/n/14/140601bq.jpg.
That picture also shows conspicuous pads on the beetle's hind leg, on the tarsi. These are "tarsal pads," or pulvilli. Among longhorned beetles such pads, when present, often exude adhesives, and facilitate holding onto objects. On male beetles they help the male hang onto the female.
Hardwood Stump Borers occur throughout the US southern states from Virginia and Florida west to Arizona and south through Mexico to northern South America.
A NON-VINING MORNING-GLORY
With the drought, much fewer wildflowers are blossoming now than at this time in recent years, but in the crisp-dry grass right beside Juniper House's back door this week a tiny, mysterious herb showed up bearing small, white flowers, as seen at http://www.backyardnature.net/n/14/140601ev.jpg.
A close-up of the flowers is at http://www.backyardnature.net/n/14/140601ew.jpg.
The blossoms with their funnel-shaped corollas arising from calyxes with long, sharply pointed sepals, and bearing inside the corollas five stamens with relatively large anthers surrounding the ovaries' long, slender styles is a very familiar flower type, but such flowers aren't "supposed" to be on short stems like this. These are morning-glory flowers, but morning-glories are supposed to be vines, and this plant obviously isn't.
However, in Mexico we've gotten used to the idea that some members of the Morning-glory Family can be other than vines -- such as the Morning Glory Tree, Ipomoea carnea, so common in the Yucatan.
And, in fact, our little doorstep plant is indeed a non-vining morning-glory. It's EVOLVULUS SERICEUS, often known as the Silver Dwarf Morning-glory or White Evolvulus, mostly occurring in tropical America from central South America north through Central America, the Caribbean and Mexico into the southern tier of US states, from Florida to Arizona.
Though our plant stands only about three finger-widths high, I read that the species can grow to a foot, so ours must be stunted by the drought.
In the Yucatan the Silver Dwarf Morning-glory is used medicinally to treat burns.
Along the road where deer and cattle keep the grass grazed so low that it looks like someone has been mowing, in a certain spot the short, green grass became speckled with pale objects, as shown at http://www.backyardnature.net/n/14/140601bu.jpg.
The pale items turned out to be spikelets produced by a tiny, low-growing grass, a whole plant of which is shown in my hand at http://www.backyardnature.net/n/14/140601bv.jpg.
The flowering heads are arranged in a special way, with spikelets arising from just one side of each of the two secondary flowering-head-stems, or rachillas, as shown at http://www.backyardnature.net/n/14/140601bw.jpg.
A close-up of individuals spikelets shows that in our plants normally each spikelet contains two florets, as shown best in the spikelet at the top, right in the picture at http://www.backyardnature.net/n/14/140601by.jpg.
When we profile grasses, often we refer to glumes, which are special scales that typically are scoop-shaped and normally situated opposite one another at the base of a spikelet's collection of florets. The last picture nicely shows the two glumes inside which two florets are held. Each floret also is protected by two glume-like scales, but floret coverings, instead of being called glumes, are referred to as the lemma and palea. In the photo we can see that this species' lemmas bear three conspicuous veins or ribs.
Grass identification is largely a matter of noticing such details of spikelet arrangement and anatomy, but also of special importance is a vegetative feature, that of the "ligule," which may or may not exist where the leaf blade meets the stem. Ligules come in many sizes, shapes and textures, depending on the grass species. This dwarf grass' ligules are shown at http://www.backyardnature.net/n/14/140601bx.jpg.
This grass' ligules are composed of very short ridge of stiff hairs, at the side of which much longer hairs arise.
The manner by which this grass' spikelets were attached to just one side of the rachillas reminded me of how it's done among the grama grasses, genus Bouteloua, so that's the first place I looked for this grass' identity. You might enjoy comparing our plant's general structure with that of the much larger Tall grama profiled at http://www.backyardnature.net/n/h/tallgram.htm.
Gramas are native prairie grasses, and maybe a dozen species might be found in our area. Our plants, much smaller that the others and with only two rachillas, soon keyed out to Buffalograss, BOUTELOUA DACTYLOIDES.
An interesting feature of Buffalograss is that the plants can be "dioecious,", with individual plants bearing flowers of only one sex, or "monoecious," with male and female flowers appearing on the same plant, and some plants might even bear flowers containing both functional male and female parts. I read that female flowers look very different from male ones, so I sought female flowers, but couldn't find any. All flowering heads of dozens of plants looked at were just like those in my photo.
Also I read that in the southern Great Plains Buffalograss can grow a foot high, which is much taller than any plant found here. Earlier, Buffalograss was a very important component of North America's short-grass prairie that stretched from southern Manitoba and Saskatchewan through the US central states into arid northern Mexico.
Our first picture shows Buffalograss growing like lawn turf. Buffalograss also is famously drought tolerant. These features haven't escaped the notice of horticulturists, who have created numerous cultivars from the species meant to serve as lawn grass . Among the best known turfgrass cultivars developed from Buffalograss are Prairie, Stampede, 609, and Density. Other cultivars intended for livestock forage include Comanche and Texoka. Researchers at the University of California Riverside and University of California Davis have hybridized a buffalograss cultivar, UC Verde, which creates a thick, green, drought-tolerant lawn for California's hot, dry summers.
I rarely see Buffalograss here, but when I do I'm pleased, for in the history of North America, the species has served magnificently, photosynthesizing endless carbohydrate for herbivores and holding prairie soil in place during untold numbers of floods and windstorms.
PLUMED COCKSCOMB, GORGEOUS BUT CREEPY
Neighbor Phred keeps a colorful flower-garden watered, and nowadays one of his most eye-catching occupants is the ankle-high dwarf cultivar shown at http://www.backyardnature.net/n/14/140601cl.jpg.
That's three plants, not one with multicolored flower heads. Often gardeners call this Plumed Cockscomb, but it's marketed under many names, including Celosia 'Plumosa' and Feathered Amaranth. The binomial most experts seem to have settled on is CELOSIA ARGENTEA, of which there are many cultivars classified into at least two broad groups. Members of the "Cristata Group" look like bright, fuzzy, somewhat vertically flattened brains, and often are called cockscombs. The "Plumosa Group," to which Phred's belongs, produce spiky flowering heads. Then there are lots of in-between types available in many sizes and colors.
Celosias are members of the Amaranth Family, noted for producing small flowers with no corollas, but rather often having the flowering head itself brightly colored, doing the corollas' job of attracting animals with brightness. Within the flowering heads, color is provided by calyxes, which in typical flowers are green, and modified leaves, or bracts. If you look closely at a flowering head you see something like what's shown at http://www.backyardnature.net/n/14/140601ck.jpg.
There's nothing there displaying symmetry or exhibiting parts suggesting sexual reproduction, such as stamens or ovaries with stigmas tipped styles. Fact is, Plumed Cockscomb's genes have been so scrambled by horticulturalists bent on getting the absolute most color out of the poor plant that if humans were to disappear, so would these mixed-up plants. Genetically, Phred's plants are tetraploids, meaning that they bear four sets of chromosomes, not the usual two sets (one from the male parent and one from the female parent).
If you look hard amidst all that colorful mess sometimes you might find a calyx, such as the pink one at http://www.backyardnature.net/n/14/140601cm.jpg.
Celosias that have had their genes minimally manipulated can produce lots of fruits that easily sprout the next season, but I just don't know if Phred's super-altered plants will produce viable seeds. I have nothing against color, but there's something here that vividly speaks to a lethal and therefore profoundly sad feature of the human condition. That is, the default hankering among most humans for more and more of brighter and brighter everything, everything... at the expense of symmetry and proportion, of elegance and naturalness, of life and sustainability.
Each time I walk by these gorgeously colorful dwarfs in Phred's garden they give me the creeps
FEATURED ESSAYS FROM THE PAST:
"The Life-Paradigm" from the September 5, 2004 Newsletter, at http://www.backyardnature.net/n/p/040905.htm.
"The Little Prince's Scarf" from the September 21, 2006 Newsletter, at http://www.backyardnature.net/n/p/060921.htm.
Best wishes to all Newsletter readers,
All previous Newsletters are archived at http://www.backyardnature.net/n/.