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

July 6, 2014

ADULT ANTLION
Many times we've looked at the conical pits excavated by antlions for catching ants and other tiny creatures that wander across sand and dust. The antlion hides in sand or dust below the pit with its pincer-like mandibles ready to clamp down on whatever slides to the pit bottom. A picture of an antlion from our BackyardNature website is at http://www.backyardnature.net/pix/doodbugl.jpg.

You can see several typical pits in dust beside my hut door in the Yucatan at http://www.backyardnature.net/n/10/100627al.jpg.

Antlions are larvae. Insect larvae are what emerge from eggs of kinds of insects that undergo complete metamorphosis (egg/larva/pupa/adult). Though antlion pits often are abundant in dry places, few of us know what antlion adults look like. This week one turned up on my neighbor Phred's garage -- looking like a damselfly with a moth's antennae. You can see it at http://www.backyardnature.net/n/14/140706al.jpg.

Notice that very unlike the larva this adult bears no pincer-like mandibles. The BugInfo.Com website tells us that " The adult antlion feeds on a variety of foods, such as nectar, pollen, or even other small insects, depending on the species of antlion" but the online Antlion page of the Encyclopaedia Britannica says that "Since the adult does not feed, the larva must consume sufficient food to sustain the adult." Whatever the case, with such small mouthparts adults certainly can't prey on small invertebrates the way they did during their larval stage.

When I pulled the camera in closer for a better look at the adult's head and antennae, the critter suddenly unfurled its two sets of wings, enabling the shot shown at http://www.backyardnature.net/n/14/140706am.jpg.

Adult antlions normally are nocturnal, and this one had been attracted to Phred's security lamp. Along with other night-fliers, mostly moths, he was found there at dawn, probably exhausted from a night of trying to navigate by the light as if it were a far-away star, but succeeding only in going in exhausting circles.

Volunteer identifier Bea in Ontario thinks our antlion might be PERUVELEON DORSALIS, a species for which little information is available, apparently documented only from Mexico, Texas and North Carolina.

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A GREEN MOTH
If you leave on an outside light at night you'll attract, confuse, exhaust and often kill an incredible number and diversity of night-navigating insects. The above antlion was surrounded by several moth species, some of which we've looked at here and some not. One moth I'd not noticed before caught my eye because it was emerald green -- not a color often turning up on moths. You can see it at http://www.backyardnature.net/n/14/140706em.jpg.

Moth's are the specialty of Bea in Ontario so of course she got to identify it. Instantly Bea recognized this as one of many species of emerald moths, meaning that they belong to the Emerald Moth subfamily the Geometrinae, of the Geometer Moth Family, the Geometridae. The "geometri" part of the names derives from the Greek meaning "Earth-measure," which refers to the caterpillars of this family, which are inchworms, and inchworms as they move along in a looping fashion appear to be measuring the Earth.

About 1,400 species of geometer moths in six subfamilies are listed just for North America, so figuring out which one we have was a challenge. Still, Bea suspects that we have NEMORIA ZYGOTARIA, and that species has been collected and confirmed here in Uvalde County, so she's probably right. You can see what a Nemoria zygotaria from Uvalde County looks like when pinned on a specimen board in the Carnegie Museum of Natural History at http://ourfcs.friendscentral.org/moths/nemoria_zygotaria.htm.

That page tells us that "Nemoria zygotaria appears to be a species unique to Texas in the US, though it is relatively common in south central Texas and has been collected over a wide range of counties in that region."

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SQUASH BUGS
My neighbor Phred had some nice summer squash plants he enjoyed watering each morning and he was anticipating the nice harvest of yellow crooknecks indicated by the presence of many flowers. However, one morning as he approached his darlings with the hose, all his plants suddenly were droopy -- more than droopy, obviously moribund and never to produce a single squash. When he looked among the leaves' petiole bases he could see what had happened: His precious plants had been attacked by Squash Bugs, ANASA TRISTIS, and you can see Phred's picture of them at http://www.backyardnature.net/n/14/140706sr.jpg.

He took a picture of one on his garage wall, shown at http://www.backyardnature.net/n/14/140706sq.jpg.

These bugs are immature, as you can see in Phred's second photo, where that bug's wings are no more than small scales covering only a small portion of the abdomen. On adults, the wings extend all the way to the tip of the rear end, and on the wings themselves reticulating veins are easy to see. If Phred had looked closely at his squash plants earlier, he'd have seen smaller versions of these immature Squash Bugs, which would have almost looked like large, gray aphids with black legs and antennae.

Since the immature Squash Bug displays several immature forms, it's clear that this speices undergoes incomplete metamorphosis, which is the case for all "true bugs" -- all members of the True Bug Order of insects, the Hemiptera. An insect undergoing complete metamorphosis, like butterflies, passes through the stages of egg --> larva --> pupa --> adult, but those with incomplete metamorphosis follow this path:egg --> nymph --> adult.

Nymphs themselves develop through several stages, or "instars," the number of stages depending on the species. Squash Bug nymphs display five nymphal stages, with each instar a little larger than the last, and with wings a little better developed.

The second part of the Squash Bug's binomial, "tristis," caught my eye because in Spanish "triste" means "sad," because it's based on the Latin "tristis" with the same meaning. I wondered if Swedish Baron Charles De Geer who named our bug in 1773 imagined how sad people would be when they saw how the bug had killed off their squash. However, looking into the matter, it's clear that De Geer was thinking of the second meaning of the Latin "tristis," which is "smells bad." In fact, Squash Bugs when bothered do emit a foul odor.

Phred asked for advice about getting rid of his bugs. From what I can see, if you really want to kill them, the best way is to just smush them with your fingers or maybe brush them off into a can of kerosene. Bugs who suck their meals through a straw inserted into the plant, and who are encased in a plastic-like exoskeleton, are pretty impervious to most insecticides, except those so disagreeable that they'll wipe out much more than just Squash Bugs on your squash.

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AN IDIOSYNCRATIC MILKWEED
Beside the little road running up the Dry Frio Valley, growing up through a pile of Ashe Juniper posts eventually to be used for building a fence, an herbaceous plant caught my eye because its leaves were similar to our abundant roadside weed the Silverleaf Nightshade, but its flowers weren't nightshade flowers and, once I looked closer, the leaves were two to a node, or "opposite," instead of the typical one leaf per node, or "alternate," of nightshades. You can see the whole thing at http://www.backyardnature.net/n/14/140706as.jpg.

On hands and knees I could see from the flowers' very distinctive form that this was a species of milkweed I'd never seen. A flower close-up is at http://www.backyardnature.net/n/14/140706at.jpg.

Flowers of most milkweed species are numerous and closely packed in ball-like inflorescences, but here each cluster included only three to seven or so loosely held flowers. Also, many milkweed species hold their inflorescences at the tips of their branches, above their leaves, but on this plant flower clusters arose lower down, from where leaves attached to the stems.

Milkweed flowers are so unusual that to get to know them you must learn special milkweed-flower concepts, such as those of the corona, horn, and gynostegium. We provide a page just on milkweed-flower anatomy at http://www.backyardnature.net/fl_milkw.htm.

If you understand typical milkweed-flower anatomy, then you'll see in our flower picture that this species' corona limbs, or "hoods," are exceptinally slender and rise far above the gynostegium. Also, most milkweed flowers are some other color than green, especially pinkish, red or white.

Our roadside milkweed was such an atypical milkweed that it was pretty easy to figure out. It's variously called the Sidecluster Milkweed, Zizotes Milkweed, Texas Milkweed, Longhorn Milkweed, Primrose Milkweed, Lindheimer's Milkweed, and other names. It's ASCLEPIAS OENOTHEROIDES, a mostly tropical plant distributed from Costa Rica north through Mexico, entering the US in southern Arizona, New Mexico, Texas and Oklahoma.

A 2008 paper by Ana Mercedes Fernández entitled "Usos de las Especies del género Asclepias" reports that in Mexico backcountry folks apply the milky latex produced by Sidecluster Milkweed to painful teeth, and despite the latex containing certain toxic alkaloids, the fruit is reported as edible. I wouldn't try eating them without cooking them and pouring off the juice, though. Elsewhere I read that traditionally Native Americans made a poultice from the plant for skin rashes.

Sidecluster Milkweed is described as growing in sandy, rocky conditions, prairies, ditches and fields, to which we can now add roadsides.

*****

BRING BACK THE MONARCHS
Over the years we've paid lots of attention to Monarch Butterflies, especially in Mexico where they overwinter. I think that each time we considered them we remarked on their dwindling populations, and the habitat destruction and insecticides causing their disappearance. This week when studying the above Sidecluster Milkweed, I came upon the MonarchWatch.Org website we've often linked to, enabling readers to have the fun of watching how each season's majestic migration proceeds, and to learn more about Monarch ecology.

This year the front page at MonarchWatch.Org invites us to join the "Bring Back the Monarchs" campaign. At the heart of the campaign is an effort to plant more milkweeds, which are the host plants for Monarch caterpillars.

I have little hope for the milkweed in our pictures, since roadsides here are mowed to lawn-grass height and, where state maintenance begins, herbicides are used. The milkweed in our pictures was surviving only because it was momentarily protected by a heap of juniper posts, which soon are to be removed.

So, Monarch numbers have dropped so low that there is a campaign to "bring them back." Yet, in this area, and most areas, if not almost all areas, milkweeds and other wildflowers are under attack as vigorously as ever, often in the name of "neatness" and "orderliness."

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THE MINT FAMILY'S FOUR NUTLETS
In North America the Mint Family, the Lamiaceae, is a large, well known and relatively easy to recognize plant family. Most (not all) of our mint species produce 4-angled or "square" stems, two leaves per stem node ("opposite" leaves), flowers that most often are bilaterally symmetrical instead of radial, and the flowers' ovaries are so deeply 4-lobed that at maturity the lobes separate into "nutlets," which most people think of as seeds, though they're actually one-seeded pieces of an ovary. All these easy-to-see features are shared to some extent with other families, especially the Vervain Family, but the Mint Family's stems tend to be most perfectly square, the flowers most obviously bilaterally symmetrical, and the ovaries most deeply 4-lobed, so when you find a plant with all these features very well developed -- especially if the plant smells "minty" -- the best bet is that it's a member of the Mint Family.

In this Newsletter we've often mentioned the four nutlets at the bottom of many mint-flower calyxes, but it's hard to photograph them because they're so small and it's dark inside that calyx.

However, the other day I was lying on the ground next to a Cedar Sage that had lost its corolla after being pollinated, and the sun was shining on the bilaterally symmetrical, somewhat hairy calyx in such a way that the 4-lobed ovary inside it was clearly visible, as you can see at http://www.backyardnature.net/n/14/140706m4.jpg.

In fact, that ovary is so mature that we can probably call the lobes nutlets. Sow a nutlet and you get a new Cedar Sage.

Our Cedar Sage page showing this gorgeously red-blossomed wildflower occurring naturally only in a handful of counties along the southern boundary of the Edwards Plateau and in adjacent Mexico is at http://www.backyardnature.net/n/h/salvia-r.htm.

*****

VOLVARIELLA MUSHROOM
In the same raised bed in which last week's Cone Cap Mushrooms turned up, also for several days after a good dousing rain a cluster arose of the ones shown at http://www.backyardnature.net/n/14/140706vv.jpg.

The cluster formed around a tuft of dark red beet leaves, the stems of which are seen in the background, providing scale for the picture, and indicating that these are smallish mushrooms, the cap up front only about two inches across (5cm).

At first glance this looks like an exceptionally nondescript mushroom, one that would be hard or impossible to identify. However, if you study the picture you see that one very important field mark gives us hope: Each mushrooms' stem arises from a little cup-like structure known as the volva. In the world of mushrooms, only a small percentage of species produce such well formed volvas. A closer look at a volva is shown at http://www.backyardnature.net/n/14/140706vw.jpg.

Notice that this volva is whitish inside but dark and quite hairy outside, and even the mushroom's lower stem is hairy. Another important feature to check when gathering information for later identification is the manner in which gills beneath the cap attach to the stem. Attachment can range from "not at all," to slightly, to broadly attached, to actually having the gills descend well down the stem. This mushroom's attachment was "not at all," forming a definite "notch" between the stem and gills. Such gills are said to be "free," and once again this is a feature of only a minority of mushroom species, so now that we're looking closely we're seeing that our plain-looking mushroom does have its idiosyncracies. You can see our mushroom's free gills and the notch between the gills and stem at http://www.backyardnature.net/n/14/140706vx.jpg.

One of the most important of all field marks when identifying mushrooms is that of spore color. I collected several gilled wedges of caps in different stages of development for making a spore print that would show the color, but none produced enough spores for a good print. The most immature wedge did produce a few -- enough to indicate that the spores were not white -- as seen at http://www.backyardnature.net/n/14/140706vy.jpg.

In that picture, radiating lines of spores are barely visible on the right side, each line corresponding to a gill releasing spores beneath the cap wedge at the left.

Despite such an inconclusive outcome, it's clear that the spores aren't white, and that really surprised me. That's because when I see mushrooms arising from such well formed volvas, the first two mushroom types to come to mind are the Amanitas, which include some of the most beautiful and deadly of all mushroom species, and the commonly occurring genus Lepiota. And both of those mushroom types produce white spores. I'd guessed that our mushroom was either an Amanita or a Lepiota, but the non-white spores prove that it's something else.

By now we'd registered such excellent field marks -- the volva, the free gills, the non-white spores -- that in the end it was relatively easy to peg our mushrooms as members of the genus Volvariella, which Michael Kuo at MushroomExpert.Com describes as an easily recognized genus because they "... have pink gills and spore prints and, as the genus name suggests, volvas at the stem base."

Pink spores... Ours don't look particularly pink to me but they could be.

It's hard to say which of several species we have. A key to Volvariella at the MushroomExpert.Com webpage leads me to VOLVARIELLA TAYLORI, and pictures of that species match ours, so that's the name we'll file this page under on the Internet.

One key feature of Volvariella taylori is that its grayish cap is finely hairy, while other species have "bald" caps. Our mushrooms' caps are definitely hairy, as shown at http://www.backyardnature.net/n/14/140706vz.jpg.

Volvariella taylori occurs practically worldwide, though apparently nowhere is it very common. It's "saprobic," meaning that it lives on decaying organic matter, such as the layer of old cow manure beneath my raised bed's soil. It's described as "growing alone or gregariously on the ground; found in woods, often near brush piles and woody debris, or in urban areas in grassy waste places," so its appearance in a raised garden bed is not to be ruled out. It's not considered poisonous, but its odor and taste, which is "like a combination of radish and bleach," as Michael Kuo says, keeps people from eating it.

*****

"HOW NATURE CHANGES US" VIDEO
I've placed a video at You Tube showing me next to a Damianita bush beside Juniper House, discoursing on the topic of "How Nature Changes Us." The video can be viewed at https://www.youtube.com/watch?v=RuszStb2KgM.

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FEATURED ESSAYS FROM THE PAST:

"A Good Use for Philosophers" from the May 31, 2009 Newsletter, at http://www.backyardnature.net/n/p/090531.htm

"Bug, Basilisk, Snake & Me" from the April 3, 2011 Newsletter, at http://www.backyardnature.net/n/p/110403.htm

*****

Best wishes to all Newsletter readers,

Jim

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