December 8, 2013
About mid slope on the hill where Juniper House sits, funny-sounding grunts, clucking and high-pitched chortling issued from treetops. It was half a dozen Fox Squirrels -- five males chasing a female in heat.
They were all behaving in a way that common-sense, everyday squirrels never would. The males acted as if they were crazy, or drunk, scrambling after the female so blindly that consistently they misjudged their footing and ran into limbs, knotholes and one another, sometimes falling on their faces, and one even tumbled from the tree onto the ground, but got up and returned to the chase so fast he didn't even seem to notice that he'd fallen.
During the chases the squirrels were so reckless and absorbed in what they were doing that they didn't seem to notice me moving around below them. One got so close that I could have reached out and touched him. Another, on an Ashe Juniper trunk, was so close I had to step back to get him all in my camera's view finder. When he noticed me he stared in such a way that suggested he realized that something was amiss, but he couldn't figure out what, and, judging by how quickly he then continued the chase, couldn't be bothered with it. You can see him at the moment he was staring at me at http://www.backyardnature.net/n/13/131208sq.jpg.
Up in the trees, the female would reach the end of a branch, turn around and scream a kind of babbling reproach or threat that kept the males at bay. But then she'd rush past them and they'd chase her again, one tree after another, around and around. As Jerry Wolff and Paul Sherman say in their 2008 book Rodent Societies: An Ecological and Evolutionary Perspective, browsable via Google Books, "The spatial and temporal dispersion of estrous females provides challenges to males."
Wolff and Sherman say that among well populated Fox Squirrel communities, when chases like this take place, the chasing males fall into two groups. Somewhat less than half the males are older, higher ranked ones competing to mate with the female, while the other males are younger, lower ranked ones who chase with less enthusiasm, and during the chase may take time out to feed or simply to rest.
The chase's evolutionary benefit is clear: The male who is fit enough to outlast or out-maneuver the others passes along his genes.
The situation isn't completely black and white, though. Sometimes when a female breaks away from the higher ranked males, a younger, lower ranked "satellite" individual may sneak in and mate with her. During a chase, the female may mate with several males; Among Gray and Red Squirrels, multiple paternity of litters has been confirmed.
Also, there's the matter of "copulatory plugs," which are common among rodents, including tree squirrels such as our Fox Squirrels. The plug forms after mating. Male Fox Squirrels guard the female for about an hour and a half, preventing other males from access to her. But female Fox Squirrels have been observed removing and eating or discarding their plugs about 75% of the time.
Beyond all this, it's assumed that inside the female the sperm, perhaps from multiple partners, compete among themselves to be the one who fertilizes the egg.
Just below Juniper House one chilly morning this week I was digging trenches in which concrete will be poured for the new large greenhouse, when a medium-size, reddish dragonfly landed on the naked dirt that later will be the greenhouse's floor. You can see it at http://www.backyardnature.net/n/13/131208df.jpg.
Just three or four days earlier we'd suffered a hard freeze, so I was a little surprised to see a dragonfly out patrolling. Apparently he was looking for a mate, because soon another one flitted by, causing my visitor to give chase. Apparently the other one gave no satisfaction, for soon my ground-visitor returned to the same spot he'd occupied before. It was surprising that two dragonflies would appear so far from the Dry Frio, which halfheartedly flows in the valley about half a mile away.
As dragonflies go, the visitor had an especially thick abdomen, and the abdomen's markings, like red ribs, also were distinctive. These traits enabled ice-bound volunteer identifier Bea in Ontario to gleefully identify our friend as the Variegated Meadowhawk, SYMPETRUM CORRUPTUM. Variegated Meadowhawks occur in most of western North America south to central Mexico, and sometimes migrate clear to the eastern coast. Sidney Dunkle in Dragonflies through Binoculars describes the Variegated Meadowhawk as "... the dragonfly most likely to be seen in the desert miles from water."
In North America we have 13 meadowhawk species -- 13 species of the genus Sympetrum. They are thought of as small to medium-size, "perky" dragonflies who tend to forage for small prey in grassy areas.
Beyond the "red skeleton" design on the thick abdomen, an important field mark distinguishing Variegated Meadowhawks from other species is that of the reddish veins running along the leading edges of each wing. Normally veins are black.
MONARCH BUTTERFLY POUCHES
On the last day of November a male Monarch Butterfly made a very late-season appearance here just below Juniper House. You can see him at http://www.backyardnature.net/n/13/131208mo.jpg.
It's easy to see that he's a male because not only are the black veins on a female's hind wings much thicker than these, but also because of the single black dot on each hind wing. Hind wings on females don't bear those dots.
The black dots are small pouches in which pheromones are produced, pheromones being chemicals secreted by animals, especially insects, that influence the behavior or development of others of the same species. Pheromones often function as attractants of the opposite sex.
In 1951 Sibyl Hausman published an article in The American Naturalist, Vol. 85, No. 825, entitled "The Scent-producing Organ of The Male Monarch." She described the gland as a slightly elevated black pouch covered with dark scales. The inner cavity is lined with tiny, black, overlapping "scent scales," or "androconia," androconia meaning "male dust." The inner wall is thin, yellowish and arrayed with tiny "scent cups," each cup of which is covered with a tiny cuticle bearing a central pore from which extends an extremely fine, hairlike scale. Between the cups are pits from which arise a kind of wider scale. The two scale types give off characteristic odors. The secretory substance has a faint, fragrant odor like that of sweet milkweed blossoms.
There's sort of a poetry here: The female lays eggs on milkweed plants, since that's what Monarch caterpillars feed on, and the male emits his pheromone smelling of the flowers she is programmed to crave.
After such a long drought and a solid freeze, this week I wondered if there'd be any new wildflowers to identify. However, it seems that there's always something different if you just look hard enough and long enough, and in different places. Thus, sprouting from a clump of soil suspended over empty air where an arroyo's rushing water had washed away the bank below it, there was a delicate, finger-high plant with dark green, leathery leaves and pale green, wafer-like fruits that seemed too large for such a small plant. You can see the whole thing at http://www.backyardnature.net/n/13/131208mw.jpg.
The wafer-like fruits instantly brought to mind certain one-seeded legumes found among certain members of the Bean Family, such as lespedeza, but leaves in that family mostly are compound and have stipules at their bases, unlike this plant's. The fruits could almost be elm samaras, but elms are trees. On and on I went disqualifying one family after another until it seemed that I was stumped. But before surrendering I looked around in the hopes of finding a plant still bearing some flowers, and there was. You can see its tiny, yellow blossom at http://www.backyardnature.net/n/13/131208mx.jpg.
Another plant bore flowers which when I touched fell off. A shed blossom better showing the flower's structure is at http://www.backyardnature.net/n/13/131208my.jpg.
Could this be anything but a blossom of the Bean Family? Notice how it appears that the two large lower petals fuse along their common sides to form a scoop-like "keel" occupied at the bottom by stamens with long, curved filaments -- exactly as with most "papilionaceous" flowers of the Bean Family. But, could any Bean Family member produce such simple leaves with no stipules? Also, the flower in the last picture is missing the top petal. And if the stamens are counted, only eight are found, instead of the ten more common for similar flowers in the Bean Family.
Eventually, with a great deal of mind searching and general blundering about on the Internet, it became apparent that our little plant was a member of the small Milkwort Family. It's POLYGALA OVATIFOLIA, often known as the Eggleaf Milkwort. On the phylogenetic Tree of Life, the small Milkwort Family stands immediately beside the Bean Family. I'd known this, but the milkwort species I've seen were herbs with tiny flowers in slender, spike-like racemes. I just hadn't known that a Polygala flower could look so much like a bean flower.
Eggleaf Milkwort is endemic to just a dozen or so counties in southwestern Texas and across the river in arid northeastern Mexico. This is a good find, a plant seldom documented in the literature.
On our hill's steep, deeply shaded eastern slope a knee-high bush with fairly large, heart shaped leaves turning yellow and about to be shed caught my eye. You can see its several slender, branching, soft-woody stems at http://www.backyardnature.net/n/13/131208cr.jpg.
Back East I might have overlooked the plant, thinking it was a runty Wild Hydrangea, but none of North America's five wild hydrangea species extend as far west as Texas, so this was something else. When I began looking closely, the first unusual field mark to be noticed was that the herbage -- which was strongly spicy-smelling -- was densely covered with stiff, spiky, whitish hairs. Moreover, the hairs were of the special kind known as "stellate," or star-shaped hairs -- with several sharp spines radiating from a common base. You can see this plant's stellate hairs on the undersurface of a leaf at http://www.backyardnature.net/n/13/131208ct.jpg.
Next I noticed that several branches were tipped with small clusters of unisexual flowers. A female flower's ovary topped with three deeply split styles, with a resulting six blackish stigmas, is shown at http://www.backyardnature.net/n/13/131208cs.jpg.
I had thought the stigmas might be blackened by recent freezes, but other pictures of the species on the Internet also show black stigmas, so this must be a regular feature.
Lately we've seen several plants with fruits, styles and stigmas like this, all in the Euphorbia or Poinsettia Family, the Euphorbiaceae, so now we know the plant's family. Moreover, within the Euphorbia Family there's a big genus whose herbage is mantled with stellate hairs just like those in our picture, and that genus is Croton. You might remember that back in August a common weed called Prairie Tea, Croton Monanthogynus, abundantly grew around Juniper House. You might enjoy comparing our present plant's fruits and stellate hairs with that species', at http://www.backyardnature.net/n/h/croton.htm.
This second Croton species isn't weedy at all, but rather a retiring species favoring limestone hills, bluffs, canyons and rocky ravines at altitudes of 1,000-4,500 feet, in central and western Texas, southern New Mexico and Arizona, and adjacent arid northern Mexico. Often it's called Bush Croton. It's CROTON FRUTICULOSUS.
Informed gardeners regard this as a good shrub for shady spots, not only because it produces attractive leaves that turn yellow in the fall, but because the herbage is highly deer resistant.
Delena Tull in Edible and Useful Plants of Texas and the Southwest: A Practical Guide reports that leaves of Bush Croton can be used to make tea, but warns that other similar-looking Croton species are skin irritants and toxic, so one should be careful.
Along a rocky arroyo -- an arroyo being a usually dry stream in arid country -- where water had scoured out a niche below an overhanging limestone ledge, a much-branched, knee-high bush leaned toward the light, its leaves turned reddish or coppery by recent freezes, as shown at http://www.backyardnature.net/n/13/131208ac.jpg.
You can see that this plant's branches are tipped with flower clusters. A close-up of a cluster appears at http://www.backyardnature.net/n/13/131208ad.jpg.
This inflorescence is past its flowering time. The slender, brownish upper part of the spike bears remains of male flowers. Each leafy item below the male section is a bract, or modified leaf, subtending a female flower. A peep into some bracts appears at http://www.backyardnature.net/n/13/131208ae.jpg.
In that picture, the bract at the lower, right folds around a green, three-lobed, more or less oval fruit topped with three deeply forked styles. We've seen unisexual flowers and this kind of fruit so frequently that already we know the plant is a member of the big Euphorbia or Poinsettia Family, the Euphorbiaceae. Within that family, a big genus noted for subtending its female flowers and fruits with deeply toothed, leafy bracts just like these is the genus Acalypha. Species in Acalypha often are known as copperleafs. In October we looked at the Round Copperleaf, Acalypha monostachya. You might enjoy comparing our present plant's features with those of the Round Copperleaf at http://www.backyardnature.net/n/h/acalypha.htm.
Our current, beneath-the-ledge copperleaf often is called the Shrubby Copperleaf. It's ACALYPHA PHLEOIDES, mainly a species of Mexico and Guatemala, but in the north it extends into the US in central and western Texas, and southern New Mexico and Arizona.
In the last picture a striking feature is that the bracts bear large stalked glands. Most similar pictures on the Internet show bracts with few or no such glands, so maybe our plant is unusual for that. However, the species is noted for being very variable. In fact, for many years our plants were regarded as "Lindheimer's Copperleafs," Acalypha lindheimeri, but the expert preparing the Acalypha section to be published in the Flora of North America considers "Lindheimer's Copperleafs" to be mere variations of Mexico's Shrubby Copperleafs.
In Mexico teas made of the Shrubby Copperleaf's aboveground parts traditionally have been used for a variety of gastrointestinal disorders. Research done in Mexico finds that the plant contains thymol, camphor and gamma-terpinene, which do indeed function as antispasmodic agents -- which means that they suppress muscle spasms.
LEAF-FLOWER WITH LEAF-FLOWERS
Back in September we looked at a delicate little wildflower called Smartweed Leaf-flower, Phyllanthus polygonoides. Back then we couldn't figure out why the plant was called a leaf-flower, since its flowers were normal-looking blossoms. You can see the tiny plant in September at http://www.backyardnature.net/n/h/leafflow.htm.
Now that the plant's flowers have been replaced by fruits, it's easy to see why leaf-flowers are called leaf-flowers. You can see the plant today, adorned with what appear to be flowers but which really are mature fruits with leafy-textured calyxes below them, at http://www.backyardnature.net/n/13/131208ph.jpg.
A close-up of a spherical, green fruit subtended by six green, white-margined sepals is at http://www.backyardnature.net/n/13/131208pi.jpg.
By now we've seen so many fruits similar to this that we know it can't belong to any plant family other than that of the ubiquitous Euphorbia or Poinsettia Family, the Euphorbiaceae.
In the above picture, to the left of the green fruit, there's a tan-colored, flower-like item lacking a fruit. That's the remains of a male flower, for flowers are unisexual in the Euphorbia Family. Notice that atop the green fruit resides a three-forked style, with each fork notched at its tip, exactly as we've seen on several other species in this family.
In September, Smartweed Leaf-flower plants looked so small and fragile that one would have guessed that they are herbaceous annuals. However, now at the plants' bases semi-woody stems arise from tiny, green sprouts preparing to emerge next spring, as shown at http://www.backyardnature.net/n/13/131208pj.jpg.
Last Saturday, the last day of November, early in the morning a male Monarch butterfly turned up in frost-killed grass just below Juniper House. He'd slowly climb a grass stem, rest, then launch into the air, flutter a few feet, land back in the grass, rest, and then climb another stem and repeat the cycle. He did this again and again, each time making it a few feet farther south. It's very late for a Monarch to appear in Texas; usually by now they have arrived at their wintering grounds in Mexico.
This year Monarch numbers are at a historical low, and have been arriving late in Mexico in tattered, disorganized flocks. In good years as many as 450 million Monarchs overwinter in Mexico. Last year the fewest in history made the trip, with only 60 million. This year the estimates are for three million.
The same day our late Monarch passed through, Jarvis in North Carolina sent a link to a recent New York Times article entitled "The Year the Monarch Didnt Appear," which you can find by Googling the article title. The piece suggests reasons why this is happening, and why honeybees are dying off, as are insects in general, and the birds who eat the insects, and the native plants who depend on pollinators, on and on, everything dying, and human activity appears to be the main cause, especially by habitat destruction and using new kinds of pesticides.
What is a person who sees all this to do? How is one to behave, to think, and feel?
When I'm faced with such hard questions I look for guidance into Nature. The idea is that Nature almost by definition works perfectly, so maybe in Nature's structure and manner of being there are models for my everyday life.
Looking into Nature -- which includes the whole Universe -- the most easily recognizable impulse making Nature what it is, is that as time passes there's more and more diversity, and Nature's components continually evolve to ever higher states of interdependence and sophistication. In spiritual terms, it's as if the Creator has cast dazzling sparks into empty space, and the sparks irrepressibly arrange themselves into a gorgeous bouquet.
Thinking like this does reveal many patterns that seem appropriate for humans. For example, Nature recycles resources, so humans also should recycle resources. Nature loves diversity, so humans should respect diversity, too
Something surprising is that such manner of thinking also highlights a hopeful feature about the human condition. The hope arises from the fact that humans and human mentality also are part of Nature. As such, maybe the same creative impulse accounting for Nature's unimaginable diversity the interdependency of its parts, and the irrepressible evolutionary trend toward ever higher sophistication, may manifest in us, as well.
In fact, most of us, when we are lucky enough to emerge from childhood without being seriously damaged or having our spirits crushed, when we can enjoy the luxury of thinking about things other than survival -- when we can be inspired by art and science, and reflect on the mystery of being alive -- we become awed by the world around us, and magnanimity and empathy spontaneously, magically, blossom within us. Isn't it so? You wouldn't expect this of a species whose evolutionary history has been that of competition with and domination of other species.
What can account for it, other than its being a manifestation of that creative current flowing throughout Nature toward evolving diversity, community, and ever higher levels of sophistication?
For the sake of the Monarchs, honeybees and the rest of Life on Earth, we can only hope that such is the case.
FEATURED ESSAYS FROM THE PAST:
"Tadpole Conclusion" from the September 8, 2002 Newsletter, at http://www.backyardnature.net/n/p/020908.htm
"Tadpole Thoughts" from the June 2, 2007 Newsletter, at http://www.backyardnature.net/n/p/070602.htm
Best wishes to all Newsletter readers,
All previous Newsletters are archived at http://www.backyardnature.net/n/.