JIM CONRAD'S
NATURALIST NEWSLETTER
Issued from Hacienda Chichen Resort
adjoining Chichén Itzá Ruins in
YUCATÁN, MÉXICO

June 27, 2010

WHITE GRUBS
In the organic garden while digging a posthole I unearthed the amber-headed, white grub shown at http://www.backyardnature.net/n/10/100627gb.jpg.

When I was a kid on the Kentucky farm digging for fishing worms I was told that such grubs, which made great bait, were cutworms. On the Internet I found that cutworms are very similar to what's shown in my hand but they're structured differently. One obvious difference is that cutworm grubs are hairless, while this grub bristles with stiff, orange trichomes. Also, the rear end of this grub looks as if it's covered with a transparent, bladdery skin, and I couldn't find a cutworm species with anything like that.

Last month, in May, we experienced a massive outbreak of the amber-colored beetles that up north we call June Bugs, or sometimes May Beetles. Each morning the veranda floor had to be swept of hundreds of dead and dying June Bugs, and sometimes the water in the commodes in the public bathroom was covered with them. Remembering that June Bugs, which are members of the genus PHYLLOPHAGA, have a grub-type larva, I looked to see what their larvae were like, and what I found was a good match with the photo. I'm guessing that the grub, then, belongs to the genus Phyllophaga.

Identifying the grub in the picture as probably a June Bug of the genus Phyllophaga wasn't much of an accomplishment. About 207 species of Phyllophaga are listed for North America, with 54 just in Florida, and I'll bet that Mexico has more than North America. The typical life history of a Phyllophaga grub is that it feeds on roots below ground, especially in grassy areas, for one or two years. Grass is killed that is fed on by these larvae but the soil itself is made looser and better aerated where they feed. In the North, life cycles are interrupted by cold weather so that the grubs have to move to below the frost line. Here there's no frost, but I wouldn't be surprised if our grubs dig deeper and maybe have a resting period during the dry season.

I got a pretty good head-shot of the grub in the above picture showing some very powerful mandibles. It's at http://www.backyardnature.net/n/10/100627gc.jpg.

Especially interesting to me in that picture are the antenna-like appendages sprouting from the blackish lower mandibles. Those aren't antennae, for the antennae emerge just below the big, orange, compound eyes at the top. I'm guessing that they're taste or odor sensors enabling the grub to monitor the chemical content of the roots it eats, so it doesn't eat something that disagrees with it.

*****

CITRON BUGS
First little green caterpillars began eating my cucumbers' flowers and leaves while they were still in the budding stage or just beginning to open, then as soon as we figured out how to control them a kind of leaf-footed bug appeared, inserting its juice-sucking proboscis into all parts of the plant. You can see one with its needlelike proboscis stuck into a tendril at http://www.backyardnature.net/n/10/100627ph.jpg.

A view of the bug's much less colorful top is shown at http://www.backyardnature.net/n/10/100627pi.jpg.

Bea in Ontario told me that this looks like a Citron Bug, LEPTOGLOSSUS GONAGRA, a member of the Leaf-footed Bug Family, the Coreidae, of the True Bug Order, the Hemiptera, which embraces true bugs. By "true bug" is meant members of the Hemiptera, recognized by their sucking, strawlike beaks, and front wings leathery and often colored at their bases but transparent at their tips. Lots of insects not in the order are referred to as bugs, so they're not "true bugs."

Insects that suck a plant's internal juices through a strawlike beak aren't affected by organic materials dusted onto the plant meant to attack the insect's intestinal system. Therefore, true bugs can be hard to control. On my cucumbers, a few days after the first Citron Bugs appeared, dozens more were appearing and my little cucumbers were yellowing, shriveling and falling off.

My friend José heard about an organic concoction consisting of two or three cups of Rue leaves (Ruta graveolens) and a whole head of garlic with several cloves, all mushed together in a liquefier, then strained, and the resulting green, garlicky juice sprayed onto the plants. So far the solution seems to work fairly well. Our problem is not having enough Rue. I'll be planting a lot later on.

My friend Margarita back in Querétaro writes that one way to fight them is to make sure the plants are healthy, especially by providing them with appropriate "biofertilizer," which here means horse manure. The immune system of healthy plants deal with insects like Citron Bugs better than those of sickly plants.

Margarita also concocts a very strong tea made with stale onions and chamomile she rescues from the local market.

Citron Bugs seem to be a problem to gardeners throughout the American tropics and even in Florida where they attack citrus and a variety of other plants. Their preferred hosts here seem to be members of the Cucumber or Squash Family -- like our cucumber vines.

*****

ANTLION FLOOR
The traditional Maya thatch-roofed hut I live in has a dirt floor, which I like. I enjoy how it feels beneath my bare feet and how you don't have to worry about tracking dirt in from the outside. Even before I moved in I knew it'd be hard to keep my feet presentable, especially the toenails, which nowadays stay pretty much black and disreputable looking.

One thing I hadn't planned on, though, is that the hut's loose, dry dirt is perfect habitat for antlions. Antlions are the larvae of a fragile-looking, damselfly-like insect. As a kid in Kentucky I was taught to call them doodlebugs. You can read about them at http://www.backyardnature.net/neuropte.htm.

Antlion larvae excavate conical pits all across the hut's dry dirt floor. A small invertebrate falls into the pit and the larva hidden in the dirt below the pit has a meal. You can see some pits beside my vine door at http://www.backyardnature.net/n/10/100627al.jpg.

Pits like that stretch all across my floor. I can't walk without smashing them, and I'm sorry about that, but it's just one of those things.

By the way, notice the ingenious manner by which the fellows set the pole around which the vine door swings atop a mostly buried, upside-down bottle with a concave bottom. That's not "traditional Maya," but it's traditional the way the Maya use whatever they have to very good effect.

*****

JARVIS'S BIRD NOTES
It's interesting to keep longtime Nature-notes. My friend Jarvis in North Carolina has been documenting bird populations along a certain route there since 1981, and now is seeing how his findings agree with general trends across the country.

For example, his datas separated into results from 1981-1990, 1991-2000, and 2001-2010, and showing the mean number of birds per route, are the following:

So his Neotropical migrants have declined drastically while the permanent resident Cardinal is holding its own or increasing. That's happening in a lot of places.

You might like to visit the Audubon Society's page entitled "List of Top 20 Common Birds in Decline" at http://stateofthebirds.audubon.org/cbid/browseSpecies.php.

*****

WILD POINSETTIA
Christmas Poinsettia's technical name is Euphorbia pulcherrima. A very common, knee-high herb presently flowering here now, often as a weed along roadsides, is the closely related EUPHORBIA HETEROPHYLLA, which goes by several English names, especially Wild Poinsettia, Mexican Fireplant, Painted Euphorbia, Fire on the Mountain and Paint Leaf. You can see it at http://www.backyardnature.net/n/10/100627eu.jpg.

Maybe you notice similarities between this plant and the Christmas Poinsettia, especially in the similar leaf shape, how the leaves cluster at the stem's top, and how the cluster's middle leaves are colored toward their bases. Of course Christmas Poinsettias are red where the plant in the picture is white. However, this is a very variable species and sometimes the leaf bases are red.

A close-up of the flowers at the cluster's center is at http://www.backyardnature.net/n/10/100627ev.jpg.

Using the black ants for scale (and they're small ants) you can see that we're seeing things at very close range. And the "flowers" are classic Euphorbia "flowers," which means that their structure is surreal.

First, the green doughnut thingies. Notice that some of them are glistening, and that an ant appears to be feeding at one. The glistening substance is nectar, so the green doughnuts are nectar glands exuding nectar the ants like. One guesses that the ants, in return for the nectar, protect the plant from herbivores who may come nibbling. And that white and green nymph at the lower right -- who knows how it fits in?

Each green nectar gland is associated with one urn- shaped structure peculiar to Euphorbia and closely related genera. The urn-shaped thing, which is about 1/8th inch across (2.5 mm) is called a cyathium. Cyathia are not flowers, but rather clusters of flowers, almost as seen among composite flowers in the Composite Family. A single cyathium is shown at http://www.backyardnature.net/n/10/100627ew.jpg.

Three main items are visible in that picture. The whitish, flowerlike, urn-shaped cyathium lies a little to the picture's left. A yellow-green nectar gland arises on the cyathium's left. Unseen inside the cyathium reside a few -- five or so -- unisexual male flowers that are so streamlined or reduced that they consist of no more than one stamen arising from its pedicel, the pedicel being a flower's stem.

The green, spherical item to the cyathium's right is the female flower, which consists of the green ovary atop a slender pedicel anchored at the cyathium's bottom inside. In other words, the cyathium's single female flower hangs outside the cyathium. There's not enough room for it inside. The white, elongate things at the green ovary's right are style segments with stigmatic areas on which pollen grains germinate.

All Euphorbia flowers are structured more or less in the same way, in cyathia, though the cyathium of each species is a little different from the cyathium of every other species -- and worldwide over 1000 Euphorbia species are recognized, so just think about it. In 2006 we met another flowering "Wild Poinsettia," a Euphorbia, Euphorbia cyathophora, so you can see how that differs from this species at http://www.backyardnature.net/yucatan/poinsett.htm.

Our current Wild Poinsettia is native from California to eastern Texas through Mexico and into much of Central America. As an invasive weed it's spread to South and Southeast Asia, where in India and Thailand it invades cotton fields and other disturbed environments.

*****

CROTON NOT A CROTON
We're at that early stage of the rainy season when many flowering plants have finished dropping fruits, but there aren't many flowering plants around. Nowadays plants are just concentrating on growing leaves and stems, keeping the landscape as green as it can be.

Just to have something to look out, then, I've begun paying more attention to the ornamentals scattered around the Hacienda. A very common one is shown at http://www.backyardnature.net/n/10/100627cr.jpg.

With such pretty leaves it's clear why that species is so frequently planted. It's the Variegated Croton, CODIAEUM VARIEGATUM, a member of the same family as the Poinsettias, Castor Bean and spurges. The species is native to southern India, Sri Lanka, Indonesia, Malaysia and the western Pacific islands. It's grown in tropical settings worldwide, and in colder climes it's kept inside in pots. It's an evergreen shrub growing up to ten feet tall (3 m), though most of ours are only about chest high and the ones up North in pots usually are smaller still.

Horticulturalists have created hundreds of cultivars from the wild species. They've developed kinds with leaves that range from roundish to very narrow, leaves that can be lobed or unlobed, leaves with and without crinkly margins, leaves whose color patterns may follow the veins, margins or appear as random blotches, and the leaves' colors can be green, white, purple, orange, yellow, red, pink -- just about anything.

The name Variegated Croton is a little misleading, since there's a big genus called Croton in this same family, but that's a different plant.

Members in the Variegated Croton's family, the Euphorbiaceae, often "bleed" copious sap when wounded, and often the sap is colored and toxic, even irritating or burning the skin. Variagated Croton's sap can cause skin eczema in some people, and if eaten in fair amounts is toxic. However, small doses of it have been used to treat gastric ulcers.

*****

HYPOGEAL AND EPIGEAL SEEDLINGS
Seeds contain stored energy to help the future plant, at germination, get a start in life. When you crack open a corn grain, the white, starchy material making up most of the grain contains that stored energy. When you split a bean, most of the starchy and/or waxy material also contain stored energy for the future plant.

Upon germination, in some plants the energy-bearing part or parts remains in place belowground, but in other plants the energy-bearing material is actually hauled to above the soil's surface, since it's stored in the seedling's first two leaves, the cotyledons.

When the starchy/waxy storage unit stays belowground as roots grow downward from it and stems and leaves grow upward from it, we speak of HYPOGEAL germination. When the energy-holding starchy/waxy stuff is stored in the cotyledons and is raised above the ground's surface, we speak of EPIGEAL germination.

While weeding the organic garden I pulled up two good examples of hypogeal and epigeal germination. You can see them, a hypogeal morning-glory seedling at the left and an epigeal Piich-tree sapling (Enterlobium cyclocarpum of the Bean Family) on the right at http://www.backyardnature.net/n/10/100627co.jpg.

Notice the Piic-tree's thick cotyledons, while the morning-glory's first two leaves are thin and veiny like regular leaves.

*****

AFTERNOON STORMS
The weather pattern these feels like a Mahler symphony that goes on forever with such ponderous but beautiful and exactly right tones that even as the work oppresses with its heaviness and duration, it charms and pleases.

It's a typical rainy-season pattern beginning with a cloudless dawn, or with dense fog that as the sun comes up at first is chill and wet, but then as it begins feeling warmer minute by minute the fog starts glowing golden, and finally lifts to form dingy, fast-scudding coagulations scooting low above. Then when the fog is burned off there's the cloudless blue sky, and by ten AM you're wet with sweat, the sun awfully hot.

By that time usually a few white cumulus clouds hang in the sky, and hour by hour those clouds grow, pure white and billowy above but with slate gray bottoms, beautiful to look at in the ever darker-blue sky, and this also is when butterflies are flitting and I like to stand in the garden letting them drink the sweat on my back and arms. Sometimes when a regular cloud passes overhead a few light raindrops fall and you wonder how rain could come from such a small, simple, isolated cloud. Lots of heat and humidity in the air, is the answer.

Despite that heat and humidity making it hard to move around, that's when I like to be out. The sheer, almost violent vigor of the moment is something I love, the way it beats down on you but you're able to stand there and face into the sky right toward the sun and keep looking at clouds and blueness and that sun there in the sky, God Herself at full throttle, almost able to hear the forest's photosynthesis, the processes of life their Ommmmmmmmmmmm all around, and your mere continuing presence there is prayer enough, if prayer be called for.

As hours pass, the clouds keep growing, and merge, and by two o'clock or so already you see where on the horizon storms are building, broad, dark-gray smudges like great bruises. By three o'clock distant thunder rumbles from one or more points on the horizon and by looking at which way the clouds are going you can halfway figure out whether on this day a storm will hit here.

Even when there's lots of thunder, nowadays the storms usually just skirt us, dropping enough rain to settle the dust but not enough to keep me from carrying water to the garden the next day.

After the shower, or maybe nothing but lots of thunder, darkness and a bit of wind, it's much cooler, and it feels so good.

The concert is ended, the piece played to its end, the concert hall dark and empty.

With darkness I crawl beneath the mosquito net, and up where the thatch roof's steep sides form a peak, a firefly sits flashing again and again, even as lightning from the receding storm flickers between my wall polls. The robins' day-long singing trails off, ending so slowly, diminuendo, and with such concentrated feeling that usually I can guess which note will be the very last note of all, the one note officially ending the day's chorus.

Black is the night, as the pygmy-owl calls, and crickets chime.

*****

Best wishes to all Newsletter readers,

Jim

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