July 21, 2008
Right after issuing last week's Newsletter Karen and I headed to Land Between the Lakes National Recreation Area, which is 170,000 acres (68,796 hectares) of uninhabited, forested land between two large TVA lakes in both western Kentucky and Tennessee. The Area's official website is at http://www.lbl.org/Home.html.
After acquiring backcountry passes we found an isolated camping spot with a gravel shoreline where Karen could look for fossils, and a swampy area with lots of interesting plants and animals for me. Gravitating to a little inlet choked with aquatic vegetation and buzzing with life, I plopped down at the water's edge next to what you can see at http://www.backyardnature.net/n/08/080721ag.jpg.
That's a solid mass of algae floating on the water's surface, and what I love about it is the bubbles. Tiny, glistening bubbles were embedded among millions of alga filaments, and bigger bubbles pushed up the algal mat from below. They were bubbles of oxygen photosynthesized by the algae.
What a pleasure seeing such vigor and perfection of process! Heavy sunlight just stung my skin and made me sweat but that algae glowingly embraced the solar energy, in the process lustily spewing out oxygen so desperately needed by us animals. On the gravel I lay on my side with my face right next to an algal mat breathing in air I figured had a lot of that newly minted oxygen and I reflected deeply on the beauty of sunlight energy traveling so far through cold, dead, empty space, falling onto the blue, green and brown Earth, and right here at my little spot this friendly algae was in very high gear doing exactly what it was meant to do, which is to live its life and in the process contribute oxygen to the broader ecosystem.
Long I lay beside the shimmering mat of bubbly, green algae exorcizing images of destruction and desecration witnessed that morning along highways leading there.
LITTLE RED DOTS IN THE ALGAE
With my nose right at the scummy water's edge I saw tiny, red, globular items sailing through the water between algae strands much faster than you'd think such tiny spheres could swim. With sweat and a world of glare in my eyes I couldn't see the blobs well but I knew they were water mites, somewhat related to ticks, and even looking a little like them. My close-up of a patch of red-dotted alga scum shows them suspended in their sparkling, bubbly green galaxy at http://www.backyardnature.net/n/08/080721am.jpg.
Many kinds of water mite exist but I suspect that these are members of the genus HYDRYPHANTES. You can see a close-up of a member of the genus at http://bugguide.net/node/view/49860.
I read that water mites metamorphose through three active stages: larva, nymph (a special kind called a deutonymph), and adult. Larvae are distinguished by having six legs. They live free but eventually attach to immature aquatic insects where they become parasitic. I've seen aquatic insect larvae affixed with tiny red dots, so that was what was going on there. Once water-mite larvae engorge on their host they drop off, remain quiet a while, and then metamorphose into deutonymphs, which have eight legs. Deutonymphs as well as adults prey on small crustaceans or aquatic insect eggs and larvae. The deutonymph grows until it metamorphoses into an adult.
In my photo it looks like I have six-legged larvae. My Golden Guide called Pond Life says that adult water mites can reach 0.2 inch long (5 mm) and that's much larger than what's in my photo.
There's life cycle information and an illustrated identification key to the class of water mites here.
Farther offshore beyond the mats of algae the water's surface of the entire little inlet, a couple of acres large, was carpeted with pondweed, as shown at http://www.backyardnature.net/n/08/080721po.jpg.
That's probably American Pondweed, POTAMOGETON NODOSUS, a native and coast-to-coast aquatic that, as in the picture, sometimes grows so thickly in shallow water that swimming or boating through it becomes difficult or impossible. For wildlife, however, it's wonderful stuff, providing basic structure for entire ecosystems in which fish, waterfowl and shorebirds are conspicuous. In the picture, the dark, slender items poking up from the water are fruiting spikes, each globular thing on the spike being a drupelike fruit containing a single seed. Below the carpet of leaves floating flatly on the water's surface each plant bears more slender submersed leaves.
Pondweeds are different enough from other flowering plants to be placed in their own family, the Pondweed Family, or Potamogetonaceae. Embracing about 80 species, the genus Potamogeton has the distinction of being the largest genus of truly aquatic seed plants of temperate regions. Weakley's Flora of the Carolinas lists about 21 species just for that area.
You can read more about American Pondweed at http://el.erdc.usace.army.mil/pmis/plants/html/potamog1.html.
The next day we shifted to another shore-side camp, now in Tennessee, and here the water was deeper, the waves bigger, breezes stiffer, and no pondweed. In the afternoon an amberwing dragonfly landed on a twig beside me and I took its picture, which you can see at http://www.backyardnature.net/n/08/080721aw.jpg.
I recalled that several amberwing species occur in the US so when I noticed this one's handsome banding on its abdomen and the especially intricate venation of its wings I began hoping that it was one of the rarer ones. However, once I brought out the field guide Dragonflies through Binoculars I saw that in Tennessee, as well as in nearly all of the eastern US, we just have one species, the Eastern Amberwing, PERITHEMIS TENERA, and that's what I had.
So this was a good example of how you can get used to seeing something and stop looking closely, and forget or even never even know that it's so pretty, and such a perfect example of what it is.
That's a male in the picture, females being browner, with clear wings banded with brown. The books says that when this species pulses its abdomen up and down while simultaneously waving its wings it's mimicking wasps and thus putting doubt into the minds of possible enemies. Males select egg-laying sites such as sticks emerging from water, then defend that territory for 3-6 yards around. When a female appears he leads her to his site and hovers above it with his abdomen upcurved. If the female accepts they mate and she plasters her eggs just above the waterline during a hovering flight.
That nicely illustrated dragonfly field guide is full of such information. If you'd like to check it out at Amazon.Com there's a link near the top of the page at http://www.backyardnature.net/amazon/insects_.htm.
A MAYFLY SUBIMAGO
Next to me when I took the above picture I noticed a mayfly on a rock. Apparently it had just emerged from its aquatic nymphal exoskeleton, because it was pale instead of the usual dark brown, and didn't seem interested in moving. The resulting picture resides at http://www.backyardnature.net/n/08/080721mf.jpg.
The mayfly's aquatic nymphs are called naiads, which pale, subadult mayflies such as the one in the picture are known as subimagoes, or duns. The subimago stage may last a day or more, then its exoskeleton splits open and the shiny, sexually mature adult, known as the imago, or spinner, emerges. Imagoes of some species, after mating, live just a few hours. In fact, adult mayflies have nonfunctional mouthparts so adults can't even eat; they just mate and die.
One reason mayflies rate a special vocabulary with such words as naiad and imago is that sometimes very attention-getting mayfly outbreaks occur, and mayflies provide food to so many birds, fish and other animals that they're very important in their local ecosystems.
In fact, the week before when we'd tarried along Ross Barnett Reservoir's western shore in central Mississippi, I'd seen evidence of an earlier mass emergence there, where vast numbers of adult mayflies had ended up clumped in spider webs along shore, shown at http://www.backyardnature.net/n/08/080721mg.jpg.
Sometimes beneath lights along shore mayfly bodies pile up a foot or more deep. You can read about one such outbreak in Wisconsin at http://www.jsonline.com/story/index.aspx?id=457479.
On the above page notice that over at the right you can click on the image and see how the mass emergence looked on radar.
Many mayfly species exist but I'm supposing that mine belongs to the genus Hexagenia. You can read about mayflies from a trout fisherman's perspective and see some interesting pictures at http://www.troutnut.com/hatch/4/Insect-Ephemeroptera-Mayflies.
At our Ginger Bay camp in Tennessee a skipper landed in grass beside me. It was a little different from other skippers I remembered so I took its picture, hoping it would turn out to be something special. See it at http://www.backyardnature.net/n/08/080721sk.jpg.
Though it didn't turn out to be really rare and it occurs over a large area -- from Minnesota east to Maine and south to Texas and Florida -- since the species hadn't registered to me before, I was tickled to find that it was the Cobweb Skipper, HESPERIA METEA, found on new grass in recently burned areas or cleared sites. Sparse, rarely-mowed grass at a lake's edge apparently fits its ecological needs.
I identified the species using the Audubon field guide. Though it's not particularly colorful or interestingly marked, somehow I derive enormous pleasure from admiring details of its anatomy -- the way white borders highlight its black, compound eyes, how sharp little spines project downward along its legs, the delicate fringe of dun-colored hairs of its wingtips.
CORNELL'S LOST LADYBUG PROJECT
"Over the past twenty years several native ladybug species that were once very common have become extremely rare," begins the page at http://instruct1.cit.cornell.edu/courses/icb344/Lost_Ladybugs.htm.
That page, produced by the Dept. of Entomology at Cornell University, describes a ladybug-monitoring project you might find interesting. The idea is to locate rare ladybug species, identify them, and send digital pictures of them to Cornell.
I was thinking about that project at our Kentucky camp when I noticed two ladybug species on a Buttonbush at the water's edge, and wondered whether either might be rare. One of them was the ladybug I grew up with in Kentucky but have seen little of in recent years, so I was particularly interested in its status. My pictures are at http://www.backyardnature.net/n/08/080721l2.jpg.
It turns out that the ladybug from my childhood, the smaller one on the left, is the Spotted Ladybug, COLEOMEGILLA MACULATA, a native to North America. She eats aphids, insect eggs, small larvae and lots of pollen, but she's not really rare.
The species on the right is the Seven-spotted Ladybug, COCCINELLA SEPTEMPUNCTATA, an alien introduced from Europe in 1956, therefore nothing to get excited about.
These identifications were made possible by a nicely illustrated, easy-to-use field guide, which you can download for free, in PDF format, by clicking here.
TIGER SWALLOWTAIL CATERPILLAR
Not all the interesting stuff last week occurred at Land Between the Lakes. At my Uncle Rock's house near Calhoun, Kentucky, one afternoon a plump, brownish caterpillar the size of a little finger came humping across the driveway's gravel. It's shown on a leaf at http://www.backyardnature.net/n/08/080721ts.jpg.
It was the caterpillar of a Tiger Swallowtail butterfly, PAPILIO GLAUCUS, and of course a marvelous thing about it was that those big "eyes" are just decorations meant to make the caterpillar look perilous to its predators. Caterpillars of this species right out of the egg are camouflaged as bird droppings. My impression is that later caterpillars with the eye markings are greenish, but caterpillar stages right before metamorphosing to the chrysalis stage are brownish.
THE TRUMPET CREEPER'S TOUCH-SENSITIVE STIGMA LOBES
The peak flowering time for Trumpet Creeper vines, CAMPSIS RADICANS, has almost passed around Natchez, but at Land Between the Lakes they were still at their peak of flowering, and I was able to photograph something I'd missed earlier in Mississippi -- their touch-sensitive stigma lobes.
First, you can see lakeside Trumpet Creeper flowers at http://www.backyardnature.net/n/08/080721td.jpg.
Now look at close-ups of a flower's bi-lobed stigma (the female part atop the ovary's style, where male pollen lands and germinates) before and then ten seconds after I touched it, nestled among anthers, at http://www.backyardnature.net/n/08/080721tc.jpg.
Touch a stigma with its two flat lobes open, and you can actually see the lobes closing up.
It's been assumed that the Trumpet Creeper's touch- sensitive stigmas help plants cross-pollinate instead of self-pollinate. A 2004 study in China, however, found that both pollen from another plant as well as a flower's own pollen caused the stigmas to close permanently. The researchers could only conclude that the stigma-closing behavior probably helps pollination somehow.
Gravel along most of Land Between the Lakes' shores often contained crinoid stems and segments of stems. Rock strata at LBL are Cretaceous in age, so crinoids eroded from those strata are ±145.5 to ±65.5 million years old. You can see a crinoid-rich rock from there at http://www.backyardnature.net/n/08/080721cr.jpg.
As a kid I called fossilized crinoid segments "Indian beads," and I strung many bracelets of them, for gravel around our family home also was rich in them.
Crinoid stems found loose and in rocks are fossils of sea animals known as sea lilies or feather stars. The segmented stems are like stacked Life Savers, atop which arises something like an upside-down, frilly-armed starfish. In fact, crinoids are members of the phylum Echinodermata, which also includes starfish, sea urchins and sand dollars. Read more about them at http://www.fossils-facts-and-finds.com/crinoids.html.
Crinoids have inhabited Earth's waters since at least the Ordovician, some 500 million years ago. However, they're still with us as "living fossils," the stalked kind mostly living in waters deeper than 600 feet.
MY TRAILER & PORCH
Some readers have expressed interest in what it's like living and working on a porch attached to a trailer half its size. The other day Karen snapped a picture of me behind the computer, and you can see it at http://www.backyardnature.net/n/08/080721me.jpg.
Referring to my notes last week on our need to overcome human genetic programming in order to save Life on Earth by behaving rationally, Bill in Illinois wrote that my line of thought fell into the realm of sociobiology, made famous by the 1975 book of ant- specialist Edward Wilson. Bill recalls that the book "elicited fierce opposition, not from religious conservatives, but from leftists, who see it (with good reason) as giving biological justification for racism, nationalism, social classes and so on." Wikipedia provides a helpful introduction to sociobiology and provides many links, some supporting the concept and others critical of it, at http://en.wikipedia.org/wiki/Sociobiology.
What's missing in the debate about sociobiology are insights offered by two of Nature's most obvious, easy-to-interpret paradigms: First, that few things are as beautiful, necessary, and sacred as diversity, and; second, things always change, always evolve.
For example, despite its being politically incorrect to say so, it should be obvious to everyone that the various human subgroups sometimes known as races are different from one another. How did this diversity arise? Humanity's ancestors evolved in different environments, each subgroup developed exquisite adaptations for its own local conditions, so today's resulting humans are programmed to function best under conditions of their ancestors' evolution.
What a majestic, interesting process and outcome this is, and I fail to see anything less than beautiful about it.
When we humans behave according to impulse and instinct we are slavishly expressing our programming. The problem with that is that behaviors programmed on the African savannah and afterwards are cumulatively destructive in today's world. Programmed behaviors such as the urge to possess more than we need and to strive for dominance over our neighbors, when multiplied by humanity's billions, threaten Life on Earth.
Happily, all human races can think, and from what I've seen all human races are equally capable of participating in the Sixth Miracle of Nature, which is to overcome our genetic programming and behave rationally.
So, human races are different from another. Great! Arabs don't live like Westerners. Stupendous! One social group finds survival harder than another...
Well, history shows that if a species, biotic community or human social group focuses its attention on what it needs and wants, and works and fights hard enough and long enough to change things, eventually things do change, sometimes for the better, sometimes in unexpected ways.
This messy, unpredictable Darwinian competition among individuals and groups is called LIFE, and it evolves and evolves.
Best wishes to all Newsletter subscribers,
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