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

October 20, 2013

GIANT CRAB SPIDER IN RETREAT
Neighbor Ron told me about a large, silken cocoon built between horizontal metal plates serving as part of a door-hinge assemblage at the local park restroom. You can see the two-inch long (5cm) cocoon at http://www.backyardnature.net/n/13/131020sr.jpg.

Opening the bathroom's door caused one side of the cocoon to pull away to reveal the cozy occupant, as shown at http://www.backyardnature.net/n/13/131020sp.jpg.

A close-up of the spider's face appears at http://www.backyardnature.net/n/13/131020sq.jpg.

We've all seen spiders' egg bags and webs of silk, but this was the first time I'd found a mature spider inside a closed silk cocoon. I hadn't known that spiders could do that. Drawing a blank on the matter, I uploaded the above photos to the spider identification forum at http://forums.spiders.us/.

Within a couple of hours an identification was posted, and our spider turned out to be a species we've already met, but not from the side as in our picture. It was the Giant Crab Spider, Olios giganeus, for whom we have some nice pictures at http://www.backyardnature.net/n/a/olios.htm.

This Southwestern US and Mexican, arid-land, nocturnal species is known to spin silken "retreats" in which it may spend the day, or to complete molting. Also, the female may spin such a retreat to stay in as she guards her egg sac and the spiderlings who emerge from the sac.

*****

ARMYWORM
While watering the raised beds of mustard and turnip greens I saw an especially plump, 1¾-inch-long (45mm) caterpillar inching among the plants. Being so large, I thought he might be looking for a place to pupate. You can see him at http://www.backyardnature.net/n/13/131020ct.jpg.

Volunteer identifier Bea in Ontario had problems figuring out who this one was, partly because so many pictures on the Internet are misidentified. Bea sent the image to experts at the Butterflies and Moths of North America website and even they took longer than usual to figure out that we had what's variously called a Velvet, Garden, or Lateral-lined Armyworm, SPODOPTERA LATIFASCIA. Bea and I had just about decided that it was Spodoptera ornithogalli, a common across most of North America. However, the BOMONA expert determined that "The line along the side just doesn't look strong and sharp enough..." to be that species. Now our picture resides at http://www.butterfliesandmoths.org/sighting_details/937273.

Velvet Armyworms are a hot-weather-loving species, in the US turning up mainly along the Gulf Coast from Texas to Florida, and south through the Americas to Argentina in South America. The caterpillars metamorphose into moths with tan and brown wings held back over their bodies. The wings are fairly unspectacular unless you look closely at the fine details.

Velvet Armyworm caterpillars are "general feeders" capable of damaging gardens, where they've been seen eating asparagus, bean, corn, cowpea, pepper, potato, sweet potato, turnip and more. In Florida they eat ornamental plants. Mainly they eat leaves, but they can function as cutworms when they remove entire plants, cutting the stem at the soil surface. Soon after hatching, the caterpillars cluster in groups, and often are parasitized by various insects who lay eggs inside their bodies, which kills them. As surviving caterpillars grow they wander off and begin eating alone.

*****

RICE WEEVILS
Inside a big jar of brown rice one morning some darkish specks caught my attention because they hadn't been there just a few days before. Looking closely, my suspicion was confirmed: Weevils. They were too small for the camera, only 2-3mm long (1/10th inch), so I poured some rice and weevils beneath the dissecting scope, and you can see what I saw at http://www.backyardnature.net/n/13/131020wv.jpg.

The spectacular thing about weevil anatomy is the presence of a long, slender, down-pointed snout. A head picture from the side showing how antennae arise at the base of the snout is at http://www.backyardnature.net/n/13/131020ww.jpg.

Googling "rice weevil" I learned that really there is such a thing, the Rice Weevil, SITOPHILUS ORYZAE. However, also I found that other very similar weevils found in kitchen jars worldwide also exist, such as the Corn or Maize Beetle and the Wheat or Granary Beetle, all of genus Sitophilus, and it's possible to find, say, Wheat Weevils in rice, and Rice Weevils in wheat. Happily, their general body shapes are slightly different, so by comparing our pictures with those on the Internet I'm fairly sure that our rice-eating weevils are genuine Rice Weevils.

Rice Weevil adults as well as their grub-like larvae feed not only on rice and wheat but also such diverse foods as dried beans, cashew nuts, wild bird seed, bean pods, boxed cereals and macaroni. Females chew a cavity into a seed, lay a single egg and seal it with a secretion from her ovipositor. The larva develops within the seed, hollowing it out while feeding, and eventually pupates inside the same grain before emerging as an adult weevil

I'd always assumed that weevils feed through the tips of their snouts but once I saw that last picture with no hint of mouthparts at the tip I began wondering. Maybe the mouthparts lie farther back, below the snout. But, no, the experts say that weevils feed with small, saw-like teeth at the very tip of their snouts. I read about the Acorn Weevil that, "The tip of the snout is actually a miniature saw, and the weevil places the tip against the {acorn's} shell, circling endlessly around the pivot point until the shell is pierced."

The suddenness with which weevils appeared in my rice jar can be explained by the fact that Rice Weevil females can lay 300 to 400 eggs. Under our hot conditions larvae can mature in a month, and adults often live for seven to eight months. Doing the math, you can see that in just two months it's possible to develop a whole weevil metropolis in a jar.

*****

SWALLOWTAIL EGG ON THE PARSLEY
A big pot of lush, dark green Parsley lives on Juniper House's deck. When I want to rest my eyes from the computer screen it's a pleasure to look out the window and see the Parsley gorging on sunlight and air, alongside other healthy, happy-looking potted plants. The other day as I worked at the computer a black-colored swallowtail turned up flitting above the Parsley, every couple of seconds dipping her abdomen's tip onto some of the top leaves. She was laying eggs. When she left, I went out to look for an egg, and on one of the topmost leaves saw what's shown at http://www.backyardnature.net/n/13/131020eg.jpg.

Black Swallowtail butterflies are known to place their eggs on plant members of the Parsley Family, the Apiaceae, so all along I figured that the egg was of that species. However, another mostly black butterfly is common here, the Pipevine Swallowtail, so when I sent the egg picture to volunteer identifier Bea in Ontario, I asked her if she could be sure it wasn't a Pipevine Swallowtail egg.

Bea pointed out that Pipevine Swallowtails lay orange eggs, while those of Black Swallowtail eggs are white, like ours. Also, Pipevine Swallowtail larvae eat ONLY plants in the Pipevine Family, while we know that Black Swallowtail caterpillars feed on the Parsley Family.

So, we're fairly sure that what we're showing here is the egg of a Black Swallowtail, whose incubation period is 11-13 days.

*****

SUNFLOWER GOLDENEYE
I met an old friend the other day, standing along the road, though I wasn't sure it was she until I "did the botany." You can see the friend at http://www.backyardnature.net/n/13/131020v0.jpg.

Notice that the pretty, yellow, daisy-type flower heads of this Composite or Sunflower Family member terminate long, stiff stems, or peduncles. You can see that the heads' eyes are yellow, not dark as with many sunflower-type heads, at http://www.backyardnature.net/n/13/131020v1.jpg.

The leaves with very finely saw-toothed, or "serrulate," margins are seen at http://www.backyardnature.net/n/13/131020v2.jpg.

Anyone familiar with wildflowers but not knowing this species, based on what we've noted so far, might guess that this is one of many species of sunflower, genus Helianthus. A general shot of the head, showing the petal-like ray flower corollas bearing notches at their tips, doesn't contradict the notion, at http://www.backyardnature.net/n/13/131020v4.jpg.

Also supportive of this being a sunflower is the fact that the cylindrical disc flowers in the head's center are fertile, but ray flowers along the head's margin bear no style arms, so do not get pollinated and do not produce viable fruits, as you can see at http://www.backyardnature.net/n/13/131020v6.jpg.

If this ray flower were fertile, two style arms somewhat in the shape of a Y would emerge from the base of the yellow corolla, at the top of the white, unformed, cypsela-type fruit.

Scales, or phyllaries, of the green involucre subtending the flower head also look like those of sunflowers, as seen at http://www.backyardnature.net/n/13/131020v3.jpg.

Finally, take a look at a longitudinal section of a flowering head, shown at http://www.backyardnature.net/n/13/131020v5.jpg.

There we see that each disc flower is partly enveloped in a scoop-shaped scale, and that atop the white, developing fruit just right of the center of the picture there is a white, pointed spine, part of the fruit's pappus. That scale is like one of the needles on Spanish Needle fruits, which stick into animal fur for free rides into new territories.

Sunflower seeds are topped with sharp scales like this, but they are very fragile and fall off easily. These scales are fairly firmly attached. So that's the first indication we have that this is not a sunflower -- not a member of the genus Helianthus.

It's the Sunflower Goldeneye, VIGUIERA DENTATA, and it's an old friend because during the middle of the Yucatan's dry season untold millions of this pretty flower form yellow walls along backcountry roads, such as those shown in a picture from the Yucatan at http://www.backyardnature.net/n/12/120122vv.jpg.

The Sunflower Goldeneye occurs throughout much of Central America, the Caribbean and Mexico, and extends into the US from Arizona to central Texas.

In several Mexican states, Sunflower Goldeneye is known as “Chimalacate” and infusions of its above-ground parts are used for the treatment of baby rash. A 2008 study by M. Canales et al in Pharmaceutical Biology reported that a compound extracted from the plant did indeed show antifungal activity against all tested fungi.

*****

FLEABANE
Here and there in grassy, open spots in the hillside woods surrounding Juniper House, as well as right beside Juniper House's back door, you see half-inch broad (13mm), daisy-type flowering heads on much-branched, slender-leafed, foot-tall stems such as those shown at http://www.backyardnature.net/n/13/131020fb.jpg.

Especially on dark, overcast or rainy days like some we've had this week, the white-rayed heads seem to hang suspended above other dark herbage. The daisy-type flower heads consist of white, petal-like ray flowers surrounding tiny, yellow, cylindrical disc flowers forming the "eye" in the heads' centers. A pretty shot of a flowering head from the top is shown at http://www.backyardnature.net/n/13/131020fc.jpg.

Most of the time when you see small daisy-type flowering heads like this with white rays and yellow discs, and both rays and discs are uncommonly slender, numerous and closely packed together, a good guess is that you're dealing with a fleabane -- a member of the genus Erigeron. Other genera share those features but fleabanes are very commonly encountered, and nearly 400 species are listed worldwide, and 173 are known from North America. So, even if you know you have a fleabane, if you want to know exactly who you have, you have to "do the botany."

At http://www.backyardnature.net/n/13/131020fd.jpg a view of the green involucre below the flowering head shows that the scale-like phyllaries are all about the same size, which is a little unusual, and they're very hairy, with the hairs not leaning close to the phyllaries' surface but rather loosely hanging outward -- all good field marks.

Also important is that this species' hairy stems bear very narrow, small, hairy leaves, as shown at http://www.backyardnature.net/n/13/131020fe.jpg.

However, the stems arise from clusters of much broader leaves tufted at the stems' bases, as seen at http://www.backyardnature.net/n/13/131020ff.jpg.

One of the best field marks, however, needs to be seen with a good magnifying glass. That is, atop the future cypsela-type fruits formed by the disc flowers there are ten or so slender, white hairs constituting the pappus, but atop the ray flowers' cypselae, there are no hairs.

All these features lead us to the Plains Fleabane, ERIGERON MODESTUS, occurring in the US south-central states, from southwestern Kansas to Arizona and central Texas, south into arid, northeastern Mexico. The Flora of North America describes its preferred habitats as "rocky or gravelly sites, sand, clay, limestone, granite, sometimes deep sand, often with oak or oak-juniper, shrubland," so the grassy spots in our oak-juniper forest are good places for them.

The Plains Fleabane has a fascinating genetic makeup. The Flora of North America says that "Erigeron modestus is a polyploid complex apparently incorporating genes from E. flagellaris, E. tracyi, elements of E divergens, and the Mexican E. pubescens Kunth; arbitrary identifications may be necessary." A polyploid is an organism having one or more extra sets of chromosomes. Some estimates suggest that 30–80% of living plant species are polyploid, and many lineages show evidence of ancient polyploidy. Polyploidy happens in various ways. Wikipedia's page on it is at http://en.wikipedia.org/wiki/Polyploid.

The Flora also says that in Texas the Plains Fleabane is not "sympatric" with any of those species of which its genetic material consists -- sympatric meaning "found in the same place."

So, all those species shared genes with one another producing a whole new species that has been able to exploit habitats in a completely new part of the world.

The name "fleabane" suggests species that are the "banes," or "the curse", of fleas, though there's little or no evidence that fleabane upsets fleas at all.

*****

LOVEGRASS
You may have to look hard to see tiny, diffusely dispersed spikelets in the inflorescence of the knee-high grass rooted at the very edge of Juniper House's back porch, shown at http://www.backyardnature.net/n/13/131020er.jpg.

A shot showing just the inflorescence, in which the spikelets are easier to see, is at http://www.backyardnature.net/n/13/131020es.jpg.

Several grass species bear tiny, dispersed spikelets, so even with such good field marks, to identify this grass you need to look at the 4mm long (5/16ths inch) spikelets, shown at http://www.backyardnature.net/n/13/131020et.jpg.

Important features to notice in that image are that the spikelet's lowest scales, the glumes, are not longer than the upper, scoop-shaped scales, which are the lemmas, and that there are only four florets present. In the inflorescence, many spikelets bear only two or three florets and are even shorter.

This grass's leaf-bases bear long, white hairs and a hairy ligule, as shown at http://www.backyardnature.net/n/13/131020eu.jpg.

When you see a grass with such a proportionally oversized, diffuse inflorescence with small spikelets containing more than one flower, probably the first genus to think of is Eragrostis. (If the spikelet has just one flower you might consider Agrostis.) Within the genus Eragrostis, our plant keys out pretty quickly because of its spikelets very small size and limited number of florets. Our grass, normally known as Bigtop Lovegrass, is ERAGROSTIS HIRSUTA, occurring in the southeastern US and deep into Mexico. It likes sandy floodplains best, but it's weedy enough to turn up along sandy roadsides and, as we see here, at our hillside doorstep.

Back on the farm in Kentucky we had this or a very similar species, which my father called Crawlgrass. That's because when he went into the fields the big inflorescences would easily detach from their parent bodies, accumulate on his feet like seaweed as one walks ashore, and somehow insinuate themselves inside his trouser legs and "crawl" up his leg as he walked.

You can understand why a grass would invest in forming such a large, airy inflorescence when you see late fall's winds blowing the broken-off inflorescences across the landscape as if they were tumbleweeds. The tumbling inflorescences disseminate tiny grains wherever the wind blows them, and a lot of heads end up collecting against fences, which may be OK, since the mower can't reach the resulting plants there.

Why Eragrostis species are called lovegrasses isn't known, but the connection between them and love is an old one.

Lovegrass grains are tiny but small birds relish eating them.

*****

JOANN'S GOLDENRODS
Newsletter reader JoAnn in central Georgia sent us a picture of an exceptionally pretty arrangement she made of various goldenrod species and a few other wildflowers. You can see it by clicking on the top image at our page featuring many of her past creations at http://www.backyardnature.net/simple/bouquets/

*****

GNARLINESS
Two mature liveoaks stand outside my window, the tree on the left healthy and bearing leaves and acorns, while the top half of the other is dead. It's normal to see large liveoaks in this area with whole, big branches dead, maybe infected with deadly Oak Wilt, though this particular tree doesn't show certain symptoms for that, other than by dying. You can see what I'm talking about at http://www.backyardnature.net/n/13/131020-_.jpg.

Whatever causes the tree's dead top, visitors suggest that I cut the branches, not for disease control but because the branches are ugly and block the view of hills across the valley.

Unless I learn that the tree should be cut to stop the disease from spreading, I'm against cutting anything. First, any tree's dead branches provide valuable service to the surrounding ecosystem: woodpeckers eating beetles that are eating decaying wood; naked branches offering perches for lichens and mosses; falling branches adding organic matter, etc.

But, more than that, I don't agree that the limbs are ugly, or that the view of hills across the valley is superior to that of the gnarly limbs themselves.

For one thing, that well formed, healthy tree on the left is like thousands of others along this slope, but there's only one tree here expressing itself in the exact schematic gnarliness as the tree on the right, and that tree seems to have something to say to me.

For, each morning as I sit looking out this window during breakfast, those contorted branches and the flaking bark empathize with my own kinked, aging joints and weather-beaten hide. They visually display my mental world populated with inconsistencies and asymmetries, my personal losses and deformations, my gradual yieldings to gravity, in fact all my general daily degradations. Yet, I would judge what I see in that tree as some kind of prettiness, and certainly something worthy of existing, at least as worthy as anything else. Maybe if a gnarly tree can please me, then my own case is not a hopeless one.

Beyond all that, when I meditate on those dead branches I get to thinking that there must be a sovereign gnarly theme flowing through the Universe and among all the dimensions, just that right now, right here, that flowing theme catches itself on and crystallizes in the dying tree, and in me. As such, each morning I find myself strung among those branches and, because gnarliness turns up in lots of places, when I go into the world I find myself among craggy rocks, in certain minor-chord, jerky kinds of music and prose, in shattered clouds and night-skies with clots of stars and summer lightning, and, conversely, all those things seem to turn up within me.

Communality... Maybe that's what the dead branches speak to me of each morning, of my being part of a flow through the Universe, the flow being eternal, but like any river always changing and evolving, so right now, right here, even this arthritic-knee kind of gnarliness on a droughty limestone hill in southwestern Texas is acceptable, maybe even lovely and hopeful.

*****

FEATURED ESSAYS FROM THE PAST:

"October Passions" from the October 27, 2008 Newsletter, at http://www.backyardnature.net/n/p/081027.htm

"Norte Nostalgia" from the January 10, 2010 Newsletter, at http://www.backyardnature.net/n/p/100110.htm

*****

Best wishes to all Newsletter readers,

Jim

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