June 17, 2012
SPINY IO MOTH CATERPILLARS
How often have I embarked on long fieldtrips only for the best discovery of the trip to turn up right outside my door? That happened last weekend. As I stepped off the porch leaving for a 20-mile bike ride into the bottomlands, within arm's length, on the underside of a Sugarberry leaf, there was what's shown at http://www.backyardnature.net/n/12/120617cc.jpg.
You can see a close-up of a single caterpillar at http://www.backyardnature.net/n/12/120617cd.jpg.
Volunteer identifier Bea in Ontario pegs these as caterpillars of the Io Moth, AUTOMERIS IO. Therefore, the 1½-inch-long (4cm) larvae in the photo are intermediate-stage instars -- partway through their several molting stages -- because Io Moth caterpillars reach 2¾ inches long (7cm) before metamorphosing. While the caterpillars are solitary during their later instars, they are gregarious in the early ones.
Io Moth caterpillars are known to eat many kinds of vegetation, including birches, clover, corn, maples, oaks, willows, roses, palms, grasses, and elms. Our Sugarberry trees are a kind of hackberry in the Elm Family. You might guess that a species capable of such omnivory might enjoy a large area of distribution, and that's the case: They're common throughout eastern North America west to Arizona and south through Mexico into Central America.
Sometime caterpillars' sharp-looking spines are perfectly harmless, but Io Moth caterpillar spines can "sting," and the larger the individual, the worse the sting. Stinging hairs are technically known as "urticating spines."
The caterpillar's spininess seems to account for the species' name, Io. In Greek mythology Io was a nymph seduced by Zeus, who changed her into a heifer to escape detection. But Hera, Zeus's wife, found out about the arrangement and sent a maddening gadfly to torture Io. The gadfly's bitefulness apparently was remembered by the namer of the Io Moth, with its caterpillar's stinging hairs.
EYED CLICK BEETLE
Another interesting insect similarly turned up right at my trailer's door, floating in the rainwater tub, struggling to get out. You can see the 1¼-inch long (33mm) beetle at http://www.backyardnature.net/n/12/120617cb.jpg.
In general form -- large and slender with parallel sides, and with the base of the bulging front part (pronotum) forming a kind of M where it meets the winged part -- I knew this was a kind of click beetle. As a kid on the Kentucky farm I learned early that if you catch a click beetle the first thing it does is to draw in its legs and antenna, exactly like the one in my hand, and then if between your fingers you hold the bug next to your ear, you can hear and sometimes very definitely feel the beetle clicking. In the picture you can see that the pronotum's rear corners (the M's legs) are prolonged backward into sharp points. These points are clicked against the wing section, and the click can be surprisingly powerful.
The first time one clicked between my fingers I was so surprised that it scared me and I dropped him, half expecting to be stung. That's exactly what the clicking is all about. You can imagine an uninitiated bird's response if such an unexpected clicking occurs just as the beetle is about to be gulped down. Also, most click beetles when placed on their backs can click so violently that they can flip themselves back onto their legs.
The click beetles I grew up with were different species than the one in the picture. In fact the Click Beetle Family, the Elateridae, holds about 9300 species worldwide -- some 965 just in North America -- all capable of clicking.
Bea in Ontario says that our picture shows the Eyed Click Beetle, ALAUS OCULATUS, one of the most common and best known click beetles of eastern North America. Adults mainly deal with reproduction, though they may take some flower nectar and plant juices. Most of the species' life cycle is spent in the larval stage as a longish, slender, honey-colored grub sometimes referred to as a wireworm, during which it preys on grubs of wood-boring beetles.
Right outside my computer-room window a Tufted Titmouse landed, took into his beak an acorn that seemed far too large for him to ever swallow or hammer open with his little bill, and flew away. You can see this at http://www.backyardnature.net/n/12/120617tt.jpg.
I've seen jays swallow acorns similarly "too large," but some jay species are known to have "expandable throats and esophagi." Jays and titmice aren't too far apart on the Phylogenetic Tree of Life, so maybe that's part of what is going on here.
Experiments with Tufted Titmice do indicate that they always choose the largest seeds they can when foraging. At a feeding station, the bigger the seed, the better. Either their gullets are more expandable than I can imagine, or their little beaks are more effective at hammering than I'd guess.
CHIPMUNK CHEEK POUCHES
Titmice aren't the only ones outside my window carrying more food than they seem capable of swallowing. A chipmunk regularly comes, stuffing his cheek pouches with acorns, as you can see at http://www.backyardnature.net/n/12/120617ch.jpg.
Those pouches are used not only to transport food but also for carrying nesting material, and when burrows are dug the excavated soil is carried away in the pouches so there'll be less chance of predators noticing the digging.
REDCEDARS WITH BLUISH CONES
In abandoned fields and along roadsides throughout the eastern US and adjacent southern Canada one of the best-known and easy-to-identify trees is the Eastern Redcedar, JUNIPERUS VIRGINIANA. In natural areas over most of its distribution it can only be confused with pines, which in aspect are more open, plus of course pines bear pine needles, not the Redcedar's overlapping scales.
Nowadays some of our Redcedars are laden with bluish, 1/5th-inch wide (5mm) cones, as shown among their scaly, much branching stems at http://www.backyardnature.net/n/12/120617ju.jpg.
Why are these "cones" and not "berries"? In this case, you just have to know the botany, because otherwise they do seem to be berries, which are pulpy fruits containing more than one seed and not splitting open at maturity. The Redcedar's fruits are cones because they are formed from several flower scales that fused together as the fruiting body enlarged. Out West where several members of the Redcedar's genus Juniperus are found (the junipers), cones on those species often consist of scales not as neatly fused as the ones on Redcedars, and they look more like regular cones. Redcedars are members of the Cypress Family, the Cupressaceae, so they're gymnosperms like pines and spruce, and you know that those trees produce cones. The Redcedar just does a good job making their cones look like berries.
Redcedars typically come in male or female trees -- they're dioecious -- though sometimes one tree can bear both male and female flowers. That explains why some of our trees are full of cones but others have none. On the ones without cones, if you look closely you can find tiny, egg-shaped, 1/8th-inch-long (3.5mm) catkins composed of clustered anthers, with their pollen released weeks ago, as shown at http://www.backyardnature.net/n/12/120617jw.jpg.
Ecologically, Eastern Redcedars are very important because they can quickly invade abandoned or burnt-over fields by way of bird poop dropped from the sky. Studies show that it takes about 12 minutes for redcedar seeds to pass through a Cedar Waxwing's guts, and seeds that do pass through germinate about three times better than those of seeds not eaten by birds.
You can see the Redcedar's bark, which comes off (exfoliates) in strips, not in plates the way it happens on some western juniper species, at http://www.backyardnature.net/n/12/120617jv.jpg.
Notice the relationship between the words redcedar and juniper. The West's several juniper species as well as our Eastern Redcedar are all members of the genus Juniperus, so they're all junipers. It's just that by tradition the East's junipers are called Redcedars.
The tree's wood is very durable, prettily colored and aromatic. When I was a kid on the Kentucky farm, people used Eastern Redcedars as their "Christmas trees," so of course when I smell the redcedar's resiny fragrance I have flashbacks to Christmases past.
Indigenous Americans once made bows from redcedar wood. Juniper oil, much used in aromatherapy, is distilled from the wood and branches. The oil is said to increase kidney function, relieve dehydration, treat ulcers, and other health problems, plus it's used in cosmetics due to its antibacterial and anti-inflammatory properties. The cones are used to flavor gin
SHUMARD OAK'S DOMATIA AND THICK ACORN CUPS
On the steep, moist sloped of a deep ravine cut into our thick covering of loess here certain large, pleasingly formed oaks have been a challenge to identify. You can see a high branch bearing bristle-margined leaves at http://www.backyardnature.net/n/12/120617qu.jpg.
The shiny, hairless undersurface of one of its leaves is shown at http://www.backyardnature.net/n/12/120617qv.jpg.
Several oak species bear leaves of this general shape and size, but most have hairy leaf undersurfaces. Only two species, the Shumard and Nuttall Oaks, bear leaves with hairless, or glabrous, leaf undersurfaces. Those two species are so similar that I'm not sure I could distinguish them using only vegetative characters. While examining the leaf in the above picture hoping for distinguishing field marks, you might notice the unusual thick tufts of light-brown hairs in vein axils along the midrib, as seen up close at http://www.backyardnature.net/n/12/120617qx.jpg.
Those are called domatia and often are used by mites for shelter and as sites for egg-laying. Notice how the domatia are open in the center, perfect for a tiny mite to back into and be partially protected. Mites using such domatia often feed on invertebrates or fungi that might damage the host tree. It's a classic mutualistic relationship. Unfortunately, leaves of both the Shumard and Nuttall Oaks provide them.
Fortunately, the oaks are treated in the free but only partly completed online Flora of North America, and there is a technical "key" for identification purposes. In the key, the two species "key out" together -- indicating their very close relationship -- and are separated on the basis of differences in their acorn cups. Acorn cups are those scaly, saucer or bowl-shaped receptacles subtending the oval acorn nut. The cups of Nuttall Oak acorns are described as less than 1.5 mm in cross section, and their inner surfaces are hairy; the cups of Shumards Oak acorns are more than 1.5mm thick, and are hairless inside, or with only a ring of hairs around the scar. Happily, beneath the oaks in our ravine plenty of last year's acorns remain, some of which are shown at http://www.backyardnature.net/n/12/120617qw.jpg.
Breaking a cup apart, I find its wall thickness averaging about 3 mm, and I see no hairs. Therefore: Shumard Oak, QUERCUS SHUMARDII.
I had leaned toward this species, because the habitat description in Flora of North America is described as moist, protected slopes like our ravine slopes, bottomlands, stream banks and poorly drained uplands. The habitat of Nuttall's Oak, Quercus texana, is described as flood plains and bottomlands, with no mention of upland slopes. However, I have noticed that our loess soils don't fit the usual soil characterizations, so in this area I don't trust habitat descriptions as much as in some places.
Shumard Oak is mostly restricted to the US Southeast, though it's found as far north as northern Ohio and Missouri. With its large acorns it contributes greatly to local wildlife.
Back on the farm in Kentucky no barnyard weed caused me more grief than the Horse Nettle, SOLANUM CAROLINENSE, a plant of which grows beside my trailer, shown at http://www.backyardnature.net/n/12/120617so.jpg.
A close-up of one of the pretty, white flowers is shown at http://www.backyardnature.net/n/12/120617sp.jpg.
The five yellow, banana-like items are anthers -- the stamens' baglike affairs in which pollen is produced. Notice that these anthers are unusual relative to other flowers' anthers in that instead of splitting along their sides to release pollen they develop holes, or pores, at their tops. That's where the pollen escapes. The green, match-stick-shaped thing arising amidst the anthers is the stigma-tipped style, the style being the ovary's "neck." The ovary, or future fruit, is hidden among the anthers' bases.
Anyone knowing a bit about wildflowers recognizes this combination of features as very characteristic of the group of plants known as nightshades, the same nightshades famous for their toxicity. Nightshades belong to the genus Solanum in the Nightshade/Tomato/Potato Family, the Solanaceae. Solanum is one of the largest of all flowering-plant genera, containing between 1500 and 2000 species, depending on your expert.
It wasn't the Horse Nettle's pretty flowers or the herbage's toxicity that gave me problems back on the farm. You can see the troublemakers at http://www.backyardnature.net/n/12/120617sq.jpg.
If you're a barefoot kid and you step on a Horse Nettle leaf with those ¼-inch long (5mm) spines poking straight up from the midrib, the spines will puncture your foot, no matter how calloused the soles are. It's unusual for spines to arise from leaf midribs. In most species if they're present at all they're along the margins or at the petiole's base.
Though Horse Nettle is native to the US Southeast, it's adapted for disturbed habitats and is a tough little plant, so it's spread throughout the US in all but the most arid and cold places, and is even becoming weedy in other countries.
Horse Nettle's yellow ripe fruits are less toxic than fruits of many nightshade members. I remember eating one or two as a kid and finding the taste a little unpleasant but I suffered no ill effects. Herbalists sometimes cook the fruit to serve as a sedative or antispasmodic.
In organic gardens sometimes Horse Nettles are welcomed because they attract certain beetles who prey on vegetable-eating insects.
Around here in open, grassy areas in dry soil on slopes, atop ridges, along roads, even in pastures where the soil has been compacted or overgrazed, there's a certain super-abundant grass that's especially conspicuous nowadays. That's because it's issuing its flowering heads comprising two or three slender, one-sided, spike-like racemes held aloft on knee-high, slender stems, as shown at http://www.backyardnature.net/n/12/120617ax.jpg.
A close-up showing two rows of spikelets held beneath a curvy, ribbonlike rachis, with purple, pollen-producing anthers dangling from the lower florets, and purple, fuzzy stigmas arising from upper florets, is shown at http://www.backyardnature.net/n/12/120617ay.jpg.
This grass is native here in the US Southeast but it now occurs throughout most of the world's moist tropics and subtropics, either as an invasive or planted as a groundcover because it's such a tough, robustly reproducing species capable of growing on poor soils. Because it occurs in so many countries it goes by a host of names. In the US Southeast it's often called Louisiana Grass. Books may refer to it as Carpet Grass. In Australia it's Durrington Grass, and other names include Mat Grass, Caratao Grass, and Narrowleaf Carpet Grass. It's AXONOPUS FISSIFOLIUS. Despite its abundance here on the Gulf Coastal Plain, it doesn't occur as far north and inland as Kentucky and Tennessee.
Its flower arrangement in chicken-foot-like heads is similar to what's seen for Bermuda-Grass, Crabgrass and Goosegrass. Those chicken-foot-heads can be pretty swaying in an afternoon breeze, and I admire the plant's toughness and vigor, but the heads do serve as wonderful platforms for ticks who also these days are abundant, and climb onto the heads and wait at knee level for bare-legged people like me to walk by.
Three Carpet Grass species -- members of the genus Axonopus -- are found in the US Southeast. Our Axonopus fissifolius is distinguished from them by its small spikelets, only about 1/10th of an inch long (2.5mm) and narrow leaves, mostly about 1/8th inch wide (4mm).
STEMONITIS SLIME MOLD
In the bottom of a deep, narrow ravine cut into the area's loess mantel I ducked beneath a dead, barkless, overhanging tree trunk. On the dry, shaded bottom of the trunk sprouted a black tuft of wispy items about ¾-inch tall (2cm), as seen at http://www.backyardnature.net/n/12/120617sm.jpg.
I'd seen pictures of such things while studying the slime molds we ran into down in the Yucatan, so a little Internet search quickly yielded the basic information about these tufts, which turned out to be the fruiting bodies, or sporangia, of a slime mold in the genus STEMONITIS. Many species of Stemonitis are recognized but they can be distinguished with certainty only with microscopic examination. Sometimes members of the genus Stemonitis are referred to as Chocolate Tube Slime, Tree Hair, and Pipe Cleaner Slime.
Already we've seen that slime molds, which are not fungi but rather their own kind of thing, experience an amazing life cycle. A spore germinates to form a wandering amoeba-like creature eating mostly bacteria, and which under certain conditions can develop a cilia tail and move about like a tadpole, or develop lobes called pseudopodia, with which it moves like a slug. As food becomes scarce these different creatures can merge into a much larger creature composed of flowing protoplasm with no cell walls, called a plasmodium. The plasmodium wanders about like a giant amoeba ingesting bacteria, spores of fungi and plants, protozoa, and particles of nonliving organic matter. At some point the plasmodium dries up and produces the clustered masses of stalked spore-producing fruiting bodies, or sporangia, shown in the photograph.
The sporangia in the photographs have already been emptied of their spores so you can see right through them.
Stemonitis slime molds are found worldwide except in the Polar Regions.
Newsletter reader and friend JoAnn in Georgia sometimes sends me pictures of her wildflower bouquets. I find them so exceptionally pretty and artfully arranged that I asked her to let me post the pictures at the BackyardNature website. We hope to add new ones from time to time. Already we have some arrangements so pretty that they are worth meditating on -- just looking at and feeling good about. You can see what we have so far at http://www.backyardnature.net/simple/bouquets/.
Of the four dogs I coexist with here, three are mellow, good-natured and rather lazy individuals but one, Maggie, is an extremely high-strung Jack Russell Terrier whose single obsession is that of hunting, barking at, digging out and killing burrowing animals such as chipmunks. She's also very focused on loyalty to the alpha dog. Since I'm outside the most, usually Maggie is right under my feet, normally looking at me disgustedly because I'm not leading her into chipmunk wars. If I sit awhile reading a book, she positions herself nearby where she can at least gaze into a tree watching for the enemy. She can do this for hours. You can see her tree-looking at http://www.backyardnature.net/n/12/120617mg.jpg.
The domestication history of Jack Russell Terriers reveals that Maggie is doing exactly what she was bred to do.
Another way of saying that is that humans programmed her to be what she is by selectively breeding her ancestors. Selective breeding for certain traits implies increasing the frequency of genes supporting behaviors desired by the breeder while reducing or deactivating genes supporting behaviors other than what the breeder wants. A mongrel's genes may dictate so many mutually contradictory impulses that the mongrel ends up just lying around. But purebred Maggie's genes give her very unambiguous orders: Dig out and slaughter chipmunks.
Maggie reminds me of myself during much of my life. Somehow I got programmed to gather information on Nature, process it, and pass it on. As a kid I used to copy information from books and rewrite it at the kitchen table just for myself, to relieve a certain compulsion that built up inside me. If you've followed my Newsletters for long, you've seen that that obsession remains intact.
I pity Maggie because she is so enslaved to her genetic programming. Why can't she just mellow out, stop disrupting her environment and simply enjoy being a normal dog? Of course the same question can be applied to me. And that leads to another question: When Maggie and I spend our days doing exactly what we want, are we exercising "free will?"
During my early years I thought that I was, but now I'm doubting it. I no longer think that if today I choose to write about a dog instead of a fungus I am exercising free will. My genes obligate me, in order to feel fulfilled, to gather, process and pass on information about Nature.
But, maybe free will does exist. If it does, I'm thinking it manifests itself in only one narrow instance: That's when we consciously decide to become more sensitive to esthetic, intellectual and/or spiritual matters, and to harmonize our lives with the world we become aware of in our higher states of awareness.
If "free will" exists, it's the freedom to decide how hard we struggle to feel, understand, and love, and then to harmonize ourselves with that blossoming, unspeakably beautiful new world we discover ourselves living in.
FEATURED ESSAYS FROM THE PAST:
"The Artful Creator" from the September 6, 2009 Newsletter, at http://www.backyardnature.net/n/p/090906.htm
"Chilly Fog & Cabbage Leaves" from the June 12, 2005 Newsletter, at http://www.backyardnature.net/n/p/050612.htm.
Best wishes to all Newsletter readers,