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

December 12, 2010

SANTOS'S BLACK MUMMY
Santos of the garden crew is not an ebullient person. Some would say he's subdued. However, when he came to the hut door this week he was chuckling as I'd never heard, for he'd done it again: Two weeks earlier he'd brought me the highly ornamented chrysalis of a Blomfild's Beauty Butterfly, last week it was a monstrously large grub, probably of a Rhinoceros Beetle, and now here he was with this thing shown at http://www.backyardnature.net/n/10/101212pp.jpg.

It was two inches long (5 cm) and as it lay in my hand it stiffly and faintly squirmed back and forth. It'd turned up in soil containing lots of rotting wood. Clearly it's the resting stage, or pupa, of a lepidopterous insect -- butterfly or moth. Most moth pupas are cocoons made of silk. Most butterflies form exposed pupas, called chrysalises, like that of our Blomfild's Beauty. However there are so many exceptions to this rule that sometimes it's hard to say whether you have a butterfly or moth pupa.

Good ol' volunteer insect-identifier Bea in Ontario knew that this would be a hard one. In the end we're comfortable saying that probably Santos had brought me a pupa of a moth belonging to the Giant Silk Moth Family. On the Internet pupae in the Subfamily Ceratocampinae look a lot like ours. I find only one giant silk moth having been collected in our area, the Imperial Moth, EACLES IMPERIALIS QUINTANENSIS.

The third part of that name, quintanensis, denotes the subspecies, and refers to the specimen having been collected in the state to our east, Quintana Roo. All Giant Silk Moths are essentially sex machines. Adult moths exit their pupa with the sole goal of finding a member of the opposite sex, mating and producing offspring. They don't even eat, having no mouthparts to enable it.

Is our pupa really that of an Imperial Moth? A list of Silk Moths of Shipstern Nature Reserve in Belize lists six Ceratocampinae for that area, though only one Eacles, and that's the Imperial Moth. "Imperial Moth" is a good, bet but not a certainty.

I reburied the pupa and hope for the same luck I had with the adult Blomfild's Beauty.

By the way, you can see why so many insects would be appearing nowadays in their pupal stages. As the dry season continues to bear down, more and more trees and shrubs lose their leaves, herbs die back and in some places it's just hard to find water. Ecologically our dry season imposes pressures and dangers every bit as critical as the North's coldness. It's a good time to go underground, to pass time until rains and flowers return, to be a pupa.

*****

TRIANGLE SPLEENWORT
Often visitors to the bathroom next to the Hacienda office pause to view the heavily shaded, eight-ft-high stone wall next to the bathroom. The wall is mantled with a luxuriant community of ferns, mosses and other tender, shade-loving herbs. Having passed the wall at least twice a day for the last year I felt sure I'd registered every plant there larger than an ant, but this week something new caught my eye. It was a fern, its smallish, deeply incised, triangular fronds shown at http://www.backyardnature.net/n/10/101212fn.jpg.

It wasn't the fronds' shapes that aroused my interest, because lots of ferns during the early stages of their development produce similarly small, triangular fronds. What struck me as unusual was the fact that the fronds bore sori -- spore-producing "fruit dots" on their lower surfaces. If these were immature fronds of fern species I'd already seen there, they wouldn't have born sori. Previously I'd not identified a fern whose mature fronds were so small and triangular shaped. This was something new.

Viewing a frond from below, with sunlight from above highlighting the sori, I saw what's shown at http://www.backyardnature.net/n/10/101212fo.jpg.

A close-up of some sori is at http://www.backyardnature.net/n/10/101212fp.jpg.

The brown, granular items spilling from beneath that curious, whitish, cellophane-like strip -- the indusium -- are not spores. They are baglike sporangia, which when mature snap open and release spores. Each sporangium contains 64 spores, so clearly fern spores are very tiny things.

Despite the fronds' small size and triangular shape ringing no bells with me, those sori looked very familiar. In the woods of both my childhood home in Kentucky and around my hermiting camps in Mississippi, one of the most common species was the Ebony Spleenwort, Asplenium platyneuron. Though its fronds were very different, its sori were the same -- long, slender, with silvery indusia along one side. You can see how similar an Ebony Spleenwort's sori are -- shown close-up in the second picture -- to this fern's at http://www.backyardnature.net/n/x/ebony-sp.htm.

The Spleenwort genus Asplenium is a big one, with about 700 species known worldwide, some 28 of which occur in North America. Frond shape in the genus is extremely diverse among the species, ranging from simple, undivided, ribbon-like blades, to "four-pinnately compound" -- the leaflets, or "pinnae," divided into further pinnae, which are divided into further pinnae, which are divided into further pinnae. Well, with such a big, variable genus, I figured that a good guess was that any fern, whatever its fronds' shape, if it bore sori like a spleenwort, probably it WAS a spleenwort.

And such was the case. Our wall fern turned out to be the Triangle Spleenwort, also called Hairy Spleenwort, ASPLENIUM PUMILUM. The online Flora of North America describes its habitat as shaded limestone boulders at or near sea level, so our shaded limestone walls have every reason to be home to the species. Triangle Spleenworts occur from a few spots in north-central Florida and Mexico south through the West Indies and Central America into South America.

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JOINT-VETCH
Embracing about 730 genera and some 20,000 species, the Bean Family, or Fabaceae, is one of the largest, most diversified of all plant families. Currently down here one of those species now flowering is exhibiting an unusual combination of features. You can see it at http://www.backyardnature.net/n/10/101212ae.jpg.

That's a joint-vetch, a member of the genus Aeschynomene. In the above picture small clusters of flowers and fruits obscurely dangle from the slender stem as it arches horizontally about knee-high over the forest floor. The flower clusters are attached at the compound leaves' petiole bases. There are joint-vetches up North, but this is a different species. I can't confirm the species ID from images on the Internet, but word descriptions lead me to believe that it's AESCHYNOMENE FASCICULARIS, distinguished from others of the genus by its completely yellow flowers.

One curious feature about joint-vetches is that while their feathery, pinnately compound leaves bring to mind mimosas, acacias, sennas and the like, their fruits look like "stick-tights" of the weedy genus Desmodium, plants which usually bear just three leaflets. Also, Desmodium legumes are covered by hooked hairs that enable the fruits to "stick tight" to fuzzy things, while the fruits of Aeschynomene fascicularis are hairless, as shown at http://www.backyardnature.net/n/10/101212af.jpg.

A close-up of some flowers showing typical features of "papilionaceous flowers" of the Bean Family -- a big upper petal called the "banner" or "standard, two side petals called "wings" and two lower petals fused along their common margin to form a boat-like "keel" -- is at http://www.backyardnature.net/n/10/101212ag.jpg.

*****

ARTILLERY PLANT
I grow lots of plants in black plastic bags for later transplanting. If you keep the bags reasonably watered, no matter what's planted in them, eventually a small, ferny herb begins carpeting the bags' soil. The herb also grows rampantly in greenhouses and on the Hacienda's moist, shaded limestone walls. You can see what it looks like in some bags of palm seedlings at http://www.backyardnature.net/n/10/101212pi.jpg.

This little herb's flowers are only about 1/50th of an inch across (0.5mm). Reduced, unisexual male and female flowers are crammed together at the bases of leaf petioles and without a microscope it's hard to make much out of them. You can see a typical sprig tip at http://www.backyardnature.net/n/10/101212pj.jpg.

This is Artillery Plant, PILEA MICROPHYLLA, a member of the Nettle Family, the Urticaceae. It's thought to be native to the American tropics, but it also shows up in the US Deep South, Asia and on Pacific Islands. Several Pilea species are known. Pilea microphylla is distinguished from them by its "entire" leaf margins (no teeth or scallops), its prostrate growth form, and its herbaceous nature.

The "Artillery" in the name refers to the fact that on sunny days the male flowers discharge their pollen forcibly, like artillery.

Members of the Nettle Family have their leaf epidermises dotted with marks formed by cystoliths. Cystoliths are variously shaped calcium carbonate crystals inside the leaves' epidermal cells. Calcium carbonate is just limestone. To a leaf-eating invertebrate, cystoliths in a leaf are like pebbles in the porridge. You can see the Artillery Plant's cystolith-ornamented lower leaf-epidermis at http://www.backyardnature.net/n/10/101212pk.jpg.

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RANDOM SQUASHES
This week Wilfrido cleaned up what remained of the traditional cornfield, or milpa. Most of the cornstalks already had been ridden down by coatis and stripped, the squash vines had died back leaving mature squash nestled among the weeds like Easter eggs, and the beans really hadn't amounted to anything this year. Mainly the job just entailed piling all the herbage into a heap for burning, and gathering all the squash in one place. You can see one corner of a large spread-out collection of squash/pumpkin fruits at http://www.backyardnature.net/n/10/101212sq.jpg.

Just how many different kinds of traditional Maya squash/pumpkin fruits are shown in that picture? We've already looked at the smallish Globe Squash, or Round Zucchini, represented in the picture's upper, left corner. It tastes like zucchini, but the others have a firmer texture and are sweeter, more like the Northern pumpkin.

Some people call the flattish, broadly ribbed fruits in the picture's center Striped Pumpkins. The one in the picture's lower, right corner is, or is close to, a Delicata. Most of the rest seem to be intermediate forms of these "pure types." As was the case with our previous Globe Squash, all these are just cultivars of the species CUCURBITA PEPO. They're like the many dog races, which eagerly intermingle if given a chance, since they're all the same species. Wilfrido thinks that all the Maya traditional squash types are shown, except for a small, black one, for which no seeds could be obtained.

Whatever they're called, it's always a pretty moment when the season's squash and pumpkins are all brought in and lined up for display, just in time for all the many fiestas celebrated at this time of year.

*****

VARIEGATED LEAVES
Next to the hut's door a variegated Pothos, Epipremnum aureum, grows in a pot. You can see one of its leaves at http://www.backyardnature.net/n/10/101212vg.jpg.

Variegated leaves appear on many ornamental plants around the Hacienda, mainly because people generally regard plants with variegated leaves as prettier than those with plain, green ones.

Once you leave the Hacienda grounds, however, and enter wild vegetation, probably you won't see any variegated leaves at all, unless it's obviously been caused by disease or physical damage. Ornamental plants maintain their variegated leaves generation after generation because gardeners take care of them. However, out in Nature variegated leaves are generally bad news. In Nature, unless caused by disease or physical damage, variegated leaves usually come about because of evolutionary/ genetic "experiments" or "mistakes." Nature always juggles the genes a tiny bit, knowing that in most cases the results will be damaging or disastrous, but that once in a blue moon something stupendous might arise.

In general, variegated plants need more light than their all-green ancestors, simply because their leaves posses less chlorophyll for photosynthesis. But the same plants may tend to scorch more under bright light than their ancestors, because their leaves contain less protective pigmentation. In natural communities, unless variegation offers an adaptive advantage such as attracting pollinators or repelling herbivores, variegated plants typically disappear, unable to compete with their non-variegated cousins.

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MANOLA ELEGANTE MATCHES
One agreeable feature of living simply is that the world forever astonishes with small, commonplace miracles. In my current life, usually this process begins even before the sun rises, as I set about lighting a hut campfire for tea water. That's when I'm always struck by the wonder of how fire can arise from a match, and how the light from a single little match illuminates the whole hut.

First, there's match chemistry to think about. I use safety matches, which means that the heads mainly contain sulfur, plus usually there's potassium chlorate, powdered glass, colorants, fillers, and a binder of glue and starch. The potassium chlorate serves as the "oxidizing agent," which here means that when it's heated it'll release oxygen, which will feed the growing fire. The matchbox's striking surface consists of powdered glass or silica, red phosphorus, binder and filler.

When a match strikes the box, glass-on-glass friction creates enough heat to convert a tiny amount of red phosphorus into white phosphorus vapor. White phosphorus vapor ignites spontaneously in air, and on the match head its heat induces the potassium chlorate to liberate oxygen, feeding the combustion until the sulfur itself starts burning, and that ignites the match's wood.

What an elegant, neatly thought-out system, and often I wonder how the person felt who first visualized the whole sequence of events, made a test match, then struck it and watched it burst into flame.

Often the first thing illuminated by the flash of my day's first struck match is the matchbox in my hand. In Mexico, in any ma and pa store from coast to coast, if you ask for matches, you're always sold the same thing. You get a prim little yellow box inside which a dainty cardboard tray slides in and out holding fifty matches. Someone in Mexico must have the monopoly on matches, but those fifty matches cost just one peso, or about nine US cents, so you wonder who'd want a monopoly like that. You can see two boxes at http://www.backyardnature.net/n/10/101212ma.jpg.

The matches are "Manola Elegante" brand and I think I can remember them from back in the 60s. Every box's front portrays the head of a young, European-type woman wearing a flowery traditional headdress, with a look on her face unsettlingly dreamy or maybe even ecstatic. On the box's reverse side there's a doll dressed in a pretty, traditional costume typical of one Mexican state or another. If you buy several boxes probably they'll all show Manola in different headdresses, and dolls wearing costumes from different states. There's not a word of advertising on the boxes. The matches themselves are excellent, lighting more dependably than their US counterparts.

So, after a job beneath the stars, start the day with a Manola Elegante flash in the darkness, the campfire's flame slowly ordering itself, then the mug of steamy lemongrass or spearmint tea. Outside the hut, gradually dawn comes on. Then there's dew in spider webs, motmots croaking through the fog, the day's first butterfly.

*****

Best wishes to all Newsletter readers,

Jim