July 13, 2018
YOUNG, CURIOUS SCRUB EUPHONIAS
Here in the early rainy season with plenty of bugs hatching and new herbage sprouting, it's common to see young birds not long from their nests out exploring their new worlds. This week I was lucky to photograph what seemed to be adolescent siblings eyeing every detail of an Aechmea bromeliad perched midway up a Huano Palm's trunk, shown at https://www.backyardnature.net/n/18/180713eu.jpg
Steve Howell in his A Guide to the Birds of Mexico and Northern Central America describes Scrub Euphonia young as looking like adult females, which display a grayish head with yellow-olive forehead, except that young birds have olive heads. In our bromeliad group the bird at the left must be a young female. Howell also says that young males quickly attain the plumage of adult males, so the two birds at the right must be young males displaying their early attained adult plumage. You can see an adult male closer up on our Scrub Euphonia page at https://www.backyardnature.net/mexnat/euphon-s.htm
It's not surprising that young euphonias would be curious about a big bromeliad's details. Euphonias often nest among bromeliads, and I bet they'll feed on the Achmea's fruits when they're ripe. You might enjoying taking a closer look at Achmea bromeliads at https://www.backyardnature.net/yucatan/aechmea.htm
*****
ANOTHER WASP NEST DISASTER
At https://www.backyardnature.net/mexnat/waspmex.htm we look at wasps that build soccer-ball-size, egg-shaped, paper nests, and feed their larvae flesh of caterpillars which the adults hunt and butcher. Dozens of "predator wasp" species are known to exist in the Yucatan and I'm unable to identify the species encountered, though it's clear that each species makes its own kind of nest, and that nests come in many sizes and shapes.
For the last year wasps have been busy tending to three or four nests suspended from the thatch roof of my hut and "porch." They don't bother me, though visitors sometimes get stung. The largest nest has hung directly above my table on the porch where I type these Newsletters. You can see it at https://www.backyardnature.net/n/18/180713wc.jpg
One morning this week at dawn I found several dozen wasps covering a Grape Tree leaf right in front of the porch. You can see them at https://www.backyardnature.net/n/18/180713wa.jpg
A close-up showing the species' characteristic markings is at https://www.backyardnature.net/n/18/180713wb.jpg
It didn't seem the right time of day and year for them to be swarming, here in the early rainy season with the heaviest rains still to come. When I sat at the porch table to think it over, I found the table and the porch's floor all around covered with small, white, bowl-shaped pieces of paper-like material, like confetti, as shown at https://www.backyardnature.net/n/18/180713wd.jpg
While sitting at the table, a piece of confetti fell onto my nose. I looked up, saw the wasp nest directly above, and realized that during the night the nest must have been attacked by army ants, in the manner already documented at the link provided at the beginning of this entry. No ants remained on the nest above me, but a few ranged about the floor, so I began looking at the hut's other nests. One of them inside hung over my sleeping place was in the process of being ravaged. I took a flash-assisted picture of a line of ants carrying robbed wasp larvae from a hole in the nest, but the picture didn't turn out. You can see it as an inset on a larger picture of the same nest made later when the light was better, at https://www.backyardnature.net/n/18/180713we.jpg
The next morning I awoke to find the hut's cement floor littered with shattered wasp nests. A flash-assisted shot of part of the floor is shown at https://www.backyardnature.net/n/18/180713wf.jpg
Woodrats living in the thatch roof, realizing that now the wasps were gone, had taken the liberty to ravage the nests, looking for larvae the army ants may have overlooked. I doubt that they found many, or any, for the ants are thorough.
Having some shattered nests handy, I was able to admire their structure. You can see how various layers of hexagonal nesting chambers fit inside one another at https://www.backyardnature.net/n/18/180713wg.jpg
While the larvae are developing, their chambers are roofed with paper. The ants tore away those roofs, and the discarded paper made the confetti that fell onto the table and floor. You can the empty chambers and remains of paper roofs at https://www.backyardnature.net/n/18/180713wh.jpg
I sent some of the above pictures to wasp-nest enthusiast Terry Prouty, who conducts a FaceBook Wasp Group at https://www.facebook.com/groups/Vespids/
Terry thought that the nest had been constructed by the New World paper wasp genus Polybia. I found four Polybia species listed for the Yucatan, but pictures of those species didn't match the appearance of the wasps found on the Grape Tree leaf. But, here the plot thickens.
I'd left a bowl-like section of chamber-bearing nest on a wall, after taking the above close-up pictures. Later in the afternoon a single wasp appeared on the section, wandering around, examining the robbed chambers. She must have smelled the nest, maybe recognizing it as her own. And this lone wasp did indeed look like Terry's Polybia. Apparently the ants had robbed nests of more than one species at the hut. I'd photographed one species but focused on the nests of another.
The more I see of the Yucatan's remarkable diversity of paper-nest-building, predator wasp species, the more I'm convinced that most nests, maybe nearly all of them, are destroyed by army ants before the colonies reach maturity. However, with the abundance of nests to be seen, it's clear that enough colonies survive to perpetuate the species.
One almost feels sorry for the wasps, but then it's remembered that as they're building their nests they kill and butcher a large number of caterpillars. And then the caterpillars themselves were feeding on plants. And the individual plants were at war with their neighboring plants, competing for sunlight, water and nutrients...
*****
A MANILA PALM'S BURSTING FLOWER BUD
At https://www.backyardnature.net/yucatan/manila-p.htm we look at one of the world's most-planted ornamental palms, the Manila Palm, looking like a miniature Royal Palm. This week the big flower bud of a Manila Palm at the rancho burst open, exposing its immature panicle of flowers, shown at https://www.backyardnature.net/n/18/180713mp.jpg
In that picture, notice the large, scoop-shaped spathe that earlier entirely covered and protected the flower cluster. Now the enlarging flower cluster is pushing the spathe upward, so that the spathe has come lose at its browning base. The flower cluster's thick branches are rosy colored, in anticipation of the strikingly red fruits.
Below the flower cluster's juncture with the trunk, notice the pale ring encircling the trunk. The ring is the scar left by the trunk-enveloping base of the petiole of the last frond to be shed from the growing tree. Many palm trunk species display such rings.
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ALBIZIA GUACHAPELE TREE
During my recent camping trip to southwestern Campeche state, on the morning of July 2nd I emerged from the woods near the entrance to Chicanná ruins, and began hiking eastward on the main highway between Chetumal and Escárcega. There at the southernmost extreme of the Yucatan Peninsula I was hoping to see plants and animals not encountered in the more arid northern part of the Peninsula. Within a few minutes, something new did turn up at the forest's edge, right beside the road. It was a fair-sized tree loaded with almost mature legume-type fruits, as shown at https://www.backyardnature.net/n/18/180713ab.jpg
Several Bean Family species produce broad, flattish pods like that, but notice the leaves. The small, oval blades lined up opposite one another along slender, yellowish stems are leaflets, not leaves. Moreover, the drooping feather-like structures bearing the paired leaflets don't themselves attack to a woody branch, but rather to yet another slender, yellowish stem. The tree was inaccessible to pulling down leaves for a closer look, but a telephoto image shows a couple of points where the yellowish stems join, at https://www.backyardnature.net/n/18/180713ad.jpg
So, this tree bears twice-compound leaves -- sometimes referred to as pinnately decompound leaves. In other words, each leaf is divided into segments, and then those segments are divided into further segments, in which case the ultimate blades are referred to as "pinnules," and each pinnule arises from a stemlike "rachilla."
Even though a fair number of Bean Family trees possess such decompound leaves -- the acacias and mimosas, for instance -- the Bean Family is so huge, and most of its species bear either non-compound or once-compound leaves, that during the identification process, noticing this feature helps whittle down the possibilities a lot.
Identification normally is much easier with flowers than with fruits, but fruits were all we had, so I took the close-up of a large fruit cluster shown at https://www.backyardnature.net/n/18/180713ac.jpg
The flattish legumes bearing several beans in each pod, and with the legume's edges thickened into wire-like seams, looked like certain species of the genus Albizia -- for example, the Lebbeck Tree, Albizia lebbeck, much planted in Yucatan's towns and cities, shown at https://www.backyardnature.net/n/10/100418ac.jpg
Scanning the Yucatan's listed Albizia species, a species turned up matching our roadside tree fairly well, and it was a good one, one not found in the Yucatan's arid northern parts. It was ALBIZIA GUACHAPELE, by some experts called Pseudosamanea guachapele, distributed from Ecuador in South America, through Central America (mostly on the Pacific slope), with a somewhat isolated population turning up in northern Guatemala and northern Belize, and just nudging into Mexico's extreme southern Yucatan Peninsula. This was a good beginning for my Campeche wanderings.
Though Albizia guachapele is little known in the English speaking world and bears no English name, it's highly regarded in countries where it does occur. It's a good-size tree often growing up to 20m tall (65ft), exceptionally to 50m (165ft). Growing fast and producing a spreading, rounded crown, it's a favorite shade tree. Its leaves make excellent forage, containing 24% protein. Its wood is of good quality for construction, and the trees are much cut for that purpose. The trunk consists of an unusually large amount of heartwood, which is a uniform yellowish-brown or rich brown with a a golden luster, and traditionally has been used for making a golden dye.
The species needs much sunlight, but thrives in a variety of well-drained soil conditions, from sandy loam to gravel and rocky. At Chicanná the soil was developed atop limestone.
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EARTHWORMS DON'T LIE
As a kid on the western Kentucky farm back in the 1950s, I liked nothing more than going fishing, usually in the little pond next to the barn. When I got old enough to bait my own hook and saw how an earthworm -- we called them fishingworms -- had to be impaled, and how it squirmed and shuddered, I got upset. My parents told me that worms don't feel, so with relief I believed them, and started baiting my own hooks with earthworms I dug myself.
Years passed and then years later one day my brain's neurons reached a certain threshold of interconnectivity, and suddenly I knew that my worms' writhing and struggling meant that earthworms do hurt when you push a hook through them. Moreover, hooks hurt fish mouths, and when you're removing a swallowed hook and the fish alternately violently twists its body and goes stiff, just like some people do when the dentist gets close to a nerve, they suffer unimaginably.
My parents had not told the truth, maybe because they believed the lie themselves, or maybe they figured that the good times our family enjoyed fishing together shouldn't be spoiled by my anxiety about worms and fish being hurt, or maybe it was something else. Whatever the case, on the day my brain's neurons reached that threshold, that was my introduction to the fact that authority figures, even loved and well-meaning ones, can lie.
Soon I saw little white lies and big lies all around and more or less got used to them. But then in highschool maybe another neuron threshold was reached, for suddenly one day when I saw TV images of US jets napalming small, rural Vietnamese villages -- and our troops were supposed to be fighting for freedom and democracy there -- I recognized a whole new kind of lie. They were lies that society's institutions tell. At the same time the war was going on, also I heard many religious folks saying viscous things about Martin Luther King and other leaders struggling for Black equality. All this, to me, was like napalming the roots of a tree, my own roots.
So, while still young, I was initiated into the reality of a world awash with lies. In recent years I've become aware of yet a third level of lying, and that's the lies that Nature tells us. She tells us her lies in the information encoded in our genetic makeups, information that manifests as human predispositions.
For example, She tells us that the best food is sweet and fatty, so we crave candy and pizzas more than carrots and tofu. Back when our distant ancestors were scouring the savanna for just anything to eat, such predispositions were helpful, were adaptive, but, not now, not with us. Nature tells us it's good to have sex with folks who turn us on, irregardless of whether a population needs more babies. She predisposes us to be patriotic, and proud of those who look like ourselves, even when leaders manipulate patriotism and racial pride for their own benefit.
Nature lies to other living things, too, not just humans. Being camouflaged is a form of lying, of saying you're not there when you are, and when an orchid flower looks like a prospective mate to a certain insect, that's lying, too.
In fact, I'm thinking that if lying is such a commonplace feature of Nature -- and humans and human thought and feeling are part of Nature -- that it must be important. Lying must be a mechanism important to the evolutionary process.
Lying must be adaptive in an evolutionary sense because at the species level it weeds out those individuals not smart and alert enough to see through the lies, thus making it less likely that the dumber and most unwary among us pass along their genes. If Nature's lie about sweets and fatty foods isn't recognized for what it is, you're more likely to die from a heart attack.
Lying also serves its purpose at higher levels. For example, if any nation reaches the point where it democratically elects a leader on the basis of provable lies, then that benighted country -- no matter how strong and influential it once was -- will pursue policies that ultimately weaken it and then destroy it.
And then humanity's evolution can proceed to higher levels without it.
*****
Best wishes to all Newsletter readers,
Jim
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