MAN TO MANTIS

The first Praying Mantis (Mantis religiosa) of the year perches on my weathered redwood fence. Barely a quarter of an inch long, his normally cryptic straw coloring stands out on the dark wood. A few days ago he and a couple hundred siblings squirmed free of their egg case, or ootheca. Very few of them will survive the summer. Chances are good that a sibling served as this little fellow's first meal, and most of those who don't fall to cannibalism will nourish some other creature in the coming months. Over the summer, the survivors will grow to a length upwards of three inches. The adult males, who fly well, are likely to wander further than their larger sisters before mating. The females of many spiders, scorpions, midges, and other arthropods enjoy their mates as post-nuptial dinners, but this behavior is most famous among the mantids. Allusions to the deadly mantis mate abound in legend and literature worldwide. One of the many colorful historical rulers of Madagascar is remembered as “The Mantis Queen.” Her henchmen were required to bring her handsome young men, then to toss them over a cliff once she was through with them.

It's common for a male Praying Mantis to lose his head when mating, and counterintuitively enough, it seems that there's a benefit in this. Not only does his sacrifice help to nourish the growing embryos of his offspring, but once his cerebral fear center is gone, his focus on the task at hand is more complete; headless mantises produce more sperm. Once fertilized, the female will carry her eggs for a month or more before laying them within a foamy, meringue-like secretion that hardens quickly into the ootheca. All the adults will die by first frost, but the oothecae will overwinter to begin the cycle anew in the spring.
Most summers I find myself taking an adult Praying Mantis captive. I never tire of watching them; their erect posture and mobile head with two large eyes give them an uncommon look of intelligence, and their rapacious nature is really fun to watch. They often tackle amazing quarry. A biologist friend told me of a mantis at a friend's ranch in Colombia that captured bats as they emerged from their daytime roosts in pockets of a woven palm ceiling. Unable to spread their wings, they could do nothing but accommodate the insect, who ate until sated, then moved on, leaving a tiny, faceless corpse to drop onto the dining table.

M. religiosa was introduced to North America accidentally at the end of the 19th century, and spread through most of the continent within a hundred years. As a boy, I tried twice to introduce them into our yard, but to no avail—both efforts were immediately frustrated by paper wasps (Polistes sp.), which consistently found and ate them within minutes. The first mantis I ever saw, though, was a native ground mantid (Litaneutria sp.) that I caught beneath a Curlyleaf Mountain Mahogany (Cercocarpus ledifolius) when I was about seven. An inch or so in length, it resembled nothing more than a gray mahogany twig. Never again have I seen one of these insects, though I've spent untold hours in such habitat—their amazingly cryptic appearance all but rules out their discovery. Children are much better than adults at finding insects, anyway. Having a head that's built more than twice as close to the ground helps a lot.
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upper: MALAYSIAN PEACOCK MANTIS (2005) acrylio 11" X 6"
lower: COSTA RICAN SCRUB MANTIS ( 1998) acrylic 51/2" x 4"

APRIL IS FOR AMBYSTOMIDS

National Poetry Month is almost over, and favorite poems have been posted all over the blogosphere. The best ones I've seen are up on Science & Politics. Leave it to Coturnix to post two (count 'em) poems about Axolotls (Ambystoma mexicanum). This post awakened in me long-repressed memories of a Wordsworth parody I read in MAD magazine as a kid--a poem that left me haunted and broken as its narrator. Without ado (or permission) I repeat it for you, to the best of my recollection:

I wandered lonely as a clod,
Just picking up old rags and bottles;
When onward on my way I trod,
I saw a host of axolotls.
Beside the lake, beneath the trees
A sight to make a man's blood freeze.

Some had handles, some were plain;
They came in blue, red, pink and green.
Some were orange in the main--
The damnedest sight I've ever seen.
The females gave a spritely glance,
The male ones all wore knee-length pants.

Now oft, when on the couch I lie,
The doctor asks me what I see.
They flash upon my inward eye
And make me laugh in fiendish glee.
I find my solace now in bottles,
And I forget them axolotls.
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illustration: GAINER--BELTED KINGFISHER--detail (1995) acrylic 30" x 20"

CARNIVALERT #3

My record with Tangled Bank, the carnival of medical and natural sciences, has been pretty pathetic lately. Last month I completely forgot to submit, and this month my submission on parental nutritional provisioning was rejected, apparently in favor of Neil Kelley's excellent post on the same topic. Neil's efforts and those of many others are all up on a Spaceballs-inspired Tangled Bank at The Inoculated Mind.
The 22nd edition of the birder's carnival, I and the Bird, is now up on Home Bird Notes.
Finally, Circus of the Spineless, the carnival of invertebrates, will be up on Get Busy Livin' or Get Busy Bloggin' next Sunday, April 30. Until then, I'll be busy writing something for them.

THOSE PLASTIC PREDATORS

Probably because our own lives change so quickly in comparison, it's our tendency to view the rest of nature as a static thing. Many will admit to no more than one period of change in the planet's history. A pair of events in last week's news, though, served to remind us how dynamic nature truly is. Evolutionary biologists can argue about how quickly morphological change occurs, but animal behavior changes constantly, and nowhere does it change more quickly than in the behaviorally complex predatory mammals.

On April 15, 7-year-old Shir Feldman was hiking with friends and family near Boulder, Colorado, when he was attacked by an 80-pound (small) female Mountain Lion (Felis=Puma concolor), some 30 yards from the parking lot. Feldman sustained a broken jaw and lacerations, minor injuries compared to those of the cat, which was killed by a Division of Wildlife officer the following day. Two days before that, 6-year-old Elora Petrasek was killed, and her mother and 2-year-old brother, Susan and Luke Cenkus were injured by a Black Bear (Ursus americanus) in Tennessee's Cherokee National Forest. Two male bears were trapped in the vicinity of the attack, and though it's likely that neither was the guilty party, both were euthanized.

These were the most recent of an escalating number of attacks on humans by large North American carnivores. The bear attack was the second recent fatality in eastern Tennessee. In 2000, a Black Bear killed 50-year old Glenda Bradley in the Great Smoky Mountains National Park—the first documented bear fatality in the Southeastern U.S. This coincidence has experts wondering if a behavioral shift is underway among Tennessee bears. As changing human attitudes replaced predator bounties with protective legislation, the large carnivore population in the lower 48 has become larger than in any time in the past century. Of course, the human population is also at an unprecedented high, so it's tempting to chalk the recent spate of attacks up to a redistribution of probability. Of the 12 recorded Black Bear fatalities in the lower 48, and the 45 fatalities in Canada and Alaska, the vast majority occurred where bears have little contact with Man, so habituation to humans can't be blamed—but that's exactly what's being blamed for the Mountain Lion attacks out west.
For several years, a number of experts warned of precisely the kind of incident that happened to Shir Feldman last week. David Baron's 2003 book, The Beast in the Garden was a response to the 1991 mauling death of 18-year old Scott Lancaster in Idaho Springs, Colorado. Barron agreed with biologists Michael Sanders and Jim Halfpenny, who believe that the behavior of Mountain Lions in Colorado's eastern Rockies is changing. The advancing urban/wildland interface and a growing population of Mountain Lions that are rarely threatened by humans add up to a dangerous mix, according to these men. The urban interface creates excellent deer habitat, which attracts the cats, who are losing their fear of man.

The behavior of large predators is indeed plastic. There are no records of North American Gray Wolves (Canis lupus) killing people, yet in Eurasia, a continent populated for 6,000 years by unarmed human shepherds, wolves are fairly aggressive. In the last half of the 20th century, 17 Europeans were killed by wolves. The small Indian subspecies C. l. pallipes is responsible for several human deaths each year.
Here in the Wasatch Mountains, Black Bears are rare. I've seen tracks just once, and when I was in high school an unfortunate bear was struck by a car about a mile from my house. Mountain Lion numbers, on the other hand, have always been healthy throughout most of Utah, and the species was always quite bold here. I can boast of far fewer Bobcat (Felis rufus) than Mountain Lion sightings, though the smaller, shyer cats are far more numerous. I've twice had Mountain Lions follow me, seemingly curious. I'm sure many of the reported “stalking”incidents that have fueled the fear in Colorado were nothing more than this kind of behavior. I'm told that the reverse was true in 20th century California: Bobcats were bold, Mountain Lions shy. British Columbia has the corner on aggressive cats, especially Vancouver Island, which holds more than its share of documented attacks. Mountain Lion behavior changes a lot geographically, and from one individual to the next. Sometimes, their behavior is just plain weird, like the Orange County, California cat that killed bicyclist Mark Reynolds in 2004, fed on and cached his body, then returned to the road and attacked a second cyclist, Anne Hjelle. The problem with trying to analyze predator attacks is not only that they vary so, but that they're still so bloody rare. With such paltry numbers, it's hard to make any meaningful generalizations, but let's give it a try, anyway. I doubt that fear of man is the only thing keeping predators from feeding regularly on us. I've noticed that certain birds, ibises (ibes?) for instance, are completely unattractive to falcons. Whatever it is about those birds, it's quite an asset, and a similar je ne sais quoi has probably been a bigger factor in our own species' survival than our brains and opposable thumbs combined. Another thing that the Cassandras fail to consider is the complete lack of evolutionary benefit to anthropophagy. Once a predator even nips a human, every effort is made to find and kill the animal. Once manifested, the behavior ends its days of reproductive success. I'll continue to roam the wilds of America without worry. If 80,000 automobile deaths every two years is an acceptable price for the benefits of that technology, a single death from large predators in the same period is a small price to pay for having them around—even if that death is yours.
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upper: CAUCASIAN LYNX (1994) watercolor 12" x 9"
center: SLOTH BEAR & INDIAN PIED HORNBILLS ( 1998) ink wash 19" x 12"
lower: GOSTOSO!--MANED WOLVES & 3-BANDED ARMADILLO (1997) acrylic 20" X 30"

A MORE ADVANCED AMBER ALE?

Don't get me wrong. If there's anything I cherish more than a great icon of art, it's seeing that icon perverted in a humorous way, even when there's not a lot of originality involved. So I got a little chuckle the other day when I saw a billboard ad for a new local microbrew featuring Michelangelo's God passing a beer to the Roddy McDowell character from Planet of the Apes. But as I closed in on the sign, I noticed a second icon being lampooned as well—one that stifled my chuckle with a little shudder.

It was that old Rudy Zallinger drawing again, Primates On Parade, or whatever it's called—probably the best-known work in the entire pantheon of scientific illustration. In the original, a gibbon-like Pliopithecus on the left appears to transform into a chimpish Proconsul, then through various stages of slouching, “inferior” hominids before emerging on the right as a modern Human. Beautifully rendered though it is, I'm not a big fan of that drawing. Not only does it imply a misleading pedigree for our species (a number of the primates pictured were clearly not human ancestors), it also feeds into the model of evolution as a “ladder,” with all of creation coveting Man's position at the top. It's kind of a creationist inspired view, where nature is improved over time, which is why advertisers love to parody Zallinger. Their product is always placed on the right: the crown of creation. If species evolved in an ecological vacuum, they might actually evolve into better adapted forms, but most often it's just a mad scramble to keep up with a changing system. We like to think of modern humans as the best adapted hominids because...well, because they're the most like us. Once we've survived as a species for 2 million years, like Homo erectus did, maybe I'll start listening to that argument.
In the interest of science, I bought a six-pack of Wasatch Evolution Ale today. I'm now pulling a bottle from the case. I've just popped the top. Not bad...fairly hoppy...a strong hint of silage in the aftertaste. Overall, I'd say I'm not likely to buy the stuff again. Nothing is so red in tooth and claw as market forces in the beer world.
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Photographs of Wasatch Beer advertising and packaging used without permission.

VANISHING OWLS OF THE WASATCH—PART II

Here on the west slope of Utah's Wasatch Mountains, the burgeoning human population has affected wildlife in many ways. Some species have been losers, others have been winners. Part I of this post was devoted to a loser, the Long-eared Owl (Asio otus), a species that appears to be particularly vulnerable to the ravages of a big winner, the Raccoon (Procyon lotor).Since writing part i, I took a couple of moonlight cross-country ski trips through the habitat where these birds like to nest in clones of Gambel's Oak (Quercus gambelii). In this open country, it is easy to listen for Longears while keeping a good distance from potential nest sites. In the more rugged country where they nest in Bigtooth Maples (Acer dentifolium), it's harder to check on them this early without disturbing them. I watched a hunting Longear the other night, and heard a pair courting a couple of weeks ago. Sadly, I also saw two Raccoons in the vicinity that same night, so my hopes for their nesting success are modest.

Since taking a sabbatical from falconry in the early '90s, I haven't spent much time in the open marshy habitat favored by the Longear's cousin, the Short-eared Owl (A. flammeus), and can't speak to its current status in this area, nor can I say much about Pygmy Owls (Glaucidium gnoma), which have always appeared to be rather uncommon around here. Unlike the misanthropic Longears, the successful Great Horned Owls (Bubo virginianus), Screech Owls (Otus asio) and Barn Owls (Tyto alba) don't mind having humans around. All three species are doing well here, and nest commonly right in Salt Lake City. Burrowing Owls (Athene cunicularia) have suffered a population drop recently, but I think this can be attributed to a drying trend over the past two decades, causing a steep decline in vole (Microtus spp.) numbers. Unable to find sufficient voles to feed on, Badgers (Taxidea taxus) have widened their menu preference to include the owls. I've never found Saw-whet Owls (Aegolius acacicus) in the city, but these birds don't seem to be otherwise picky about their habitat, and appear to be doing well in many areas.

The last local owl species is in many ways my favorite. The gregarious little Flammulated Owl (Otus flammeolus) lives in old mixed forests at high elevation. When I found my first Flammulated colony at age 13, the literature described it as one of North America's rarest owls, and I thought I'd found my ticket to ornithological stardom. Actually, in the proper habitat, they can be exceedingly common, they are just very hard to observe, as they normally stay more than 20 feet from the forest floor, where their beautiful black, white, gray and cinnamon plumage is usually obscured by thick foliage. Summer is short at the altitude these birds prefer, and their appetite for insect prey can only be satisfied during four months. The youngsters develop very quickly, and leave the nest, an abandoned hole of a Hairy Woodpecker (Picoides villossus) or Williamson's Sapsucker (Sphyrapicus thyroideus), at about three weeks of age. Unlike our other local owls, the Flammulateds actually fly some distance south for the winter.

Dependent as these birds are on old, dead standing trees, they have come into direct conflict with the ghastly subdivisions that seem to proliferate like cheatgrass up every draw. Unfortunately, such subdivisions spread within a mile of both Wasatch Flammulated colonies I knew. In a preemptive effort to protect their ostentatious investments from fire, the human residents cleared all the dead wood from the area, and the Flammulated colonies were annihilated. So far, discreetly placed nest boxes have remained unused, but I continue to experiment with different locations and designs. Today I built four new boxes with a slightly smaller aperture that I'll install later this week. I only hope that a lack of nesting sites is the only thing keeping the owls away. I fear that the tidying of dead wood may have reduced insect numbers below a point critical for the Flammulateds.
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illustration: FLAMMULATED OWL (1990) acrylic 15" x 20"

WELCOME, BOOK REVIEW LINKERS!

If you're reading this post, chances are good that you linked here from one of two very nice web reviews that came out this week for my new book. Please take some time to look around the place while you're here. Sorry about the mess—it doesn't usually look like this, honest.
If you're a veteran reader of this blog, please have a look at these reviews, I'm kinda proud of 'em. I was very honored to have DarkSyde ask me for an interview, which we conducted the other day. It's posted on this morning's Daily Kos, along with some very nice remarks about the book, and several images. For a more in-depth review of the book itself, you can't do better than the one Grrlscientist posted at Living the Scientific Life. I really like this review, not only because it's very positive, but because it's very well written, and she obviously paid close attention to both my artwork and my text, and she really “got” it. Nothing could be more gratifying to me than that.

For more on the book you can go here. To order it, go to Eagle Mountain Publishing.
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upper: STILL LIFE WITH BEETLES (2000) acrylic 20" x 26"
lower: CRASH-BARRIER WALTZER--BLACK-BILLED MAGPIE (2005) acrylic 30" x 20"

TO DRILL OR NOT TO DRILL

Ever since the March 16th passing of the US Senate's $2.8 trillion budget resolution for 2007, which included a $3 billion benefit from gas and oil leasing on the Arctic National Wildlife Reserve (ANWR), I've been deluged with letters and emails from conservation groups urging me to act immediately to save the refuge. What actions do they urge me to take? Improve my home's insulation? Ride my bicycle to work? Don't be silly! All I have to do to save ANWR is write them a check!

The debate about whether or not to drill in ANWR has been brewing quite publicly for several years, so you'd think we'd all understand the situation pretty well by now, but I think I speak for more than my share when I say I'm still a bit lost. A couple of years ago I went to a public ANWR forum sponsored by the local chapter of one of the big national conservation groups, in hopes of gaining some insight on the issue. I'm not quite sure what I expected, but insight was not what I got--just overblown hyperbole and self-righteous chest thumping about how good ANWR is and how bad “Big Oil” is. It reminded me of George Bush's vilification of Saddam Hussein. Making Exxon or Hussein look bad isn't much of a task, folks; once you resort to lying and exaggerating, you've lost me. When the bluster and finger-pointing ended, we all left the building, and practically every individual got into his/her own automobile. Half an hour was required to drain the cars from the parking lot, leaving a lingering hydrocarbon perfume.

This exemplified the American conservationist's dilemma. We don't want logging but we want wood products. We don't want electrical plants but we want electricity. We don't want population growth but we want families. We don't want oil drilling and we want to be able to hop in our car and drive across town to talk about how much we don't want it. The real enemies of wilderness in this country are not the miners and ranchers, but our own pursuit of an ever higher standard of living and our paradigm of continual economic growth. Most of the major conservation groups, I'm afraid, have completely bought into these models. In most cases, less good comes from donating $1,000 to a conservation group than from simply failing to earn it in the first place.

Our entire reality is based on the fact that for the past century, we've had essentially free energy in the form of petroleum. Soon, perhaps very soon, the supply will be increasingly difficult to extract, and increasingly more expensive, both monetarily and ecologically. Right now, the question I'd like to be able to answer is, “What kind of oil production does the least ecological harm?” I've seen appalling degradation in the Gulf of Guinea, where some 15% of America's petroleum originates. Here in Utah, much of our local oil production is small scale stuff that has a comparatively minimal impact. The problem with these little operations is that each one has the potential to explode overnight into a huge "city" like the Jonah Field, where the sage steppes have been rendered useless for wildlife.

The Arctic National Wildlife Refuge comprises 19 million acres (about the size of Maine) in the northeast corner of Alaska, dwarfing the oil fields at Prudhoe Bay, to the west. The entire area lies above the Arctic Circle, and is divided into three sections. The southern 9.16 million acre parcel runs mostly through the Brooks Range, and is designated as a refuge. To the north of that lies 8.31 million acres of legal wilderness. It is the 1.5 million acres of coastal plain, an area slightly larger than Delaware, in the northwest section of ANWR that is in dispute. This is the so-called 10-02 area, which has a complicated legal designation. If I understand correctly, it has always been open to oil and gas exploration, but only with prior congressional approval.

I have never been to the arctic and have little knowledge of arctic ecology. I'm still unsure where ANWR oil drilling would fall on the scale of ecological destruction, but it's clear that neither the oil interests nor the conservation interests will be of much help in figuring that out.
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upper: ULTIMA THULE--MUSK OXEN (1989) acrylic 15" x 20"
lower: GRAY GYRFALCONS (1999) acrylic diptych 15" x 20"; 30" x 20"

SCIENCE BLOGGING

In the four months that I've been involved in the blogosphere, I've come to appreciate the science bloggers above the rest. Possibly the most hyperactive member of that community is Coturnix, who has posted an excellent guide to that world on his main blog, Science and Politics. If you have any interest in science whatsoever, spend some time at his post.

OH CAECILIAN, YOU'RE RAKIN' MY HIDE

Here's a special treat for all of you who were freaked out by my description of parental care in Dendrobates frogs. Don't thank me, thank afarensis, who alerted me to the story the day before it came out in the journal Nature.

Parental care is no rare thing in nature, nor is the nutritional provisioning of young. Most multicellular animals are supplied with yolk in early development, and certain creatures, like the Strawberry Poison Frog (Dendrobates pumilio) continue that process longer than others. Mammals, of course, secrete milk for their offspring. A strategy related to the poison frogs' is found in certain spadefoots (Scaphiopus spp.), toad-like amphibians found mostly in semi-arid lands of the western U.S. Spadefoots spend most of their lives in a state of torpor underground, but when the rains come, they emerge from their burrows to feed and breed. Since the eggs are laid in temporary pools, the young develop very quickly. Typical frog tadpoles feed on algae, but those of some spadefoots come in two forms: a regular algae-eater and a bulldog-jawed carnivorous morph. In a rainy year, large, long-lasting pools provide plenty of algae, and the herbivorous forms are more successful. In a dry year, small ephemeral pools concentrate the larvae, and the edge goes to the carnivorous ones, who eat their vegetarian siblings.

All of these forms of parental provisioning require great physical investment from the mother. An exceptional new provisioning strategy was recently discovered in the East African caecilian Boulengerula taitanus. Caecilians comprise the poorly-known amphibian order Gymnophiona, which is found throughout the tropics. Usually well under a foot in length, they resemble carnivorous earthworms, and live a similar, fossorial lifestyle, with the exception of the aquatic South American family Typhlonectidae. Most of them are unexceptional to look at, but a few are beautifully colored. A screaming canary yellow species is found on the island of Sao Thomé, in the Gulf of Guinea. Like other amphibians, caecilians develop in a variety of ways. Some give birth to live young, others lay eggs. An aquatic larval stage is present in some, other genera skip the larval stage altogether (direct development).

The African genus Boulengerula includes five egg-laying, direct-developing species. The female Boulengerula guards her eggs—no small surprise, this behavior is well documented in caecilians, but the authors of the Nature paper discovered something peculiar when they took 21 female B. taitanus into captivity along with their broods. The young caecilians were feeding on their mother's skin! During brooding, the female's epidermal cells undergo a transformation that includes a doubling in thickness and production of lipid-rich vesicles. The hatchlings have complex juvenile teeth of various shapes that are specialized for scraping and biting the skin. These are eventually replaced by simpler adult teeth. There was no sign of young B. taitanus feeding on anything but their mother. This behavior is not likely to be restricted to this species, or even to the genus Boulengerula. In the '90s the authors observed juvenile brooding, juvenile teeth and maternal skin whitening in the South American caecilian Siphonops annulatus. Although skin feeding was just discovered, the behavior has probably been occurring since the Mesozoic. Similar teeth are found in certain live-bearing caecilians, and it is thought that these young engage in prenatal feeding of the maternal oviduct lining. The authors suggest that skin feeding was a transitional behavior in the evolution of oviduct feeding. Bon appétite!

For more on B. taitanus see the post at microecos.
Special thanks to Lara Carroll.
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upper: CALL OF THE MONSOON--COUCH'S SPADEFOOT (1996) acrylic 18" x 12"
lower: Photograph of Boulengerula boulengeria by Louis Porras

CARNIVALERT #2

Edition #51 of Tangled Bank, the Carnival of the Natural and Medical Sciences has temporarily taken the form of Seattle, Washington. Take a virtual tour at Discovering Biology in a Digital World.
After that, it's time to relax with some good books and a cup of strong coffee. Seth at Cup O' Books is hosting I and the Bird #21. Visit him and peruse the many posts about birds and the people they fascinate, but beware: I dropped a couple hundred bucks on books before clicking on the first post!

INCIDENTAL SUBJECTS

I enjoy peppering my paintings with little incidental subjects: mildly interesting animals and plants that put the subject into context. Admittedly not as fun to explore as the real thing, but not bad, and the mosquitos aren't nearly as ferocious. Click onto the accompanying painting and see how many of the following subjects you can spot. It will help if your monitor is better than mine.

Field Mushrooms (Agaricus sp.), Milfoil Yarrow (Achilles millifolium), Northern Sweetvetch (Hedysarum boreale), Tapertip Onions (Allium acuminatum), Big Sagebrush (Artemisia tridentata), Curlycup Gumweed (Grindelia squarrosa) Common Dandelion (Taraxacum officianale), Early Paintbrush (Castilleja chromosa), Oregon Grape (Berberis repens), cinquefoil (Potentilla sp.), Utah Serviceberry (Amelanchier utahensis), Plains Prickly-pear (Opuntia polyacantha), daddy-long-legs (family Phlangiidae), spittlebug (Philaemus sp.), Banana Assassin Bug (Fitchia aptera), velvet ant (Dasymutilla sp.), Nuttall's Sheep Moth (Hemileuca nuttalli), tent worm (Malacosoma sp.), Sagebrush Lizard (Sceloporus graciosus), Ferruginous Hawk (Buteo regalis).
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illustration: DISCIPLINE--FERRUGINOUS HAWK (1995) acrylic 40" x 30"

GLIDERS AND THE EVOLUTION OF FLIGHT

Last week, Coturnix linked to a NY Times article about Cephalotes atratus, the gliding Neotropical ant, and the research being done by Stephen Yanoviak and Robert Dudley. The next day, Neil Kelley started up his brand new blog with more thoughts on the subject and a great head-shot of the rudder-faced Daceton. Yanoviak and Dudley are hoping their work will shed new light on the evolution of insect flight, and it got me to thinking about the subject of flight in general.

Animal flight has evolved a number of times, producing three types of wing. The most obvious category is the unique bird wing, a powerful foreleg with degenerate hand bones, and a flying surface composed of feathers: complicated integumentary derivatives found in no other animal group. It is likely that all modern birds are descended from a group of small Jurassic feathered dinosaurs. Various creative intermediate uses for flight feathers have been proposed, including bipedal Coelophysis-like dinosaurs with feathered “butterfly nets” for hands. It seems likely, though, that the first winged birds were arboreal creatures that glided feebly from one tree to the next, much like some of the Madagascan couas (Coua spp.) do today.
Forest trees tend to exhibit a phenomenon known as “crown shyness,” where canopy growth stops before a tree reaches its neighbor. This not only slows the spread of tree pests and pathogens, but complicates the lives of arboreal animals. The ability to move from tree to tree without coming to the ground is of great benefit, and skills at leaping and gliding are a dime a dozen among tree dwellers. Most flying animals probably began their phylogenic careers as arboreal gliders. Among gliders, lift is provided most commonly by the second type of wing, with a patagium, or skin membrane. A number of tropical treefrogs of the families Rhacophoridae and Hylidae use gliding patagia that are nothing more than exaggerated webbed feet. Several geckos can parachute to some degree, using webbed feet and flattened tails. These are most developed in the Asian genus Ptychozoon, which also sports skin flaps along the sides of the head and body. The 28 or so lizards of the Asian genus Draco have five to six pairs of elongated false ribs supporting colorful patagia that give them unparalleled gliding skills. The active Asian tree snakes of the genus Chrysopelea can expand their ribs and flatten their bodies to extend their leaps across tree gaps. Patagia stretched from wrists to ankles have developed independently in at least three mammal groups, the squirrels, possums and colugos. The Mesozoic pterosaurs flew on patagia supported by elongated pinkie fingers, and Matt over at the Hairy Museum of Natural History just alerted me to Sharovipteryx, an amazing Triassic gliding reptile with a "delta-wing" patagium supported by elongated hind legs. Modern bats, with patagia supported by all four limbs and four pairs of fingers, are the most accomplished patagium flyers of all.

Insect wings are quite different from the others. In the typical insect design, two pairs of wings sprout from the thoracic segment, above three pairs of legs. This is not much of a departure from the basic segmented arthropod pattern seen in shrimp and lobsters, where each leg is paired with a gill. Legs and gills are modified to form other structures like mouthparts and swimerettes. It seems quite likely that insect wings are homologous to, and evolved from, gills. If this is truly the case, I can't see much chance of insect wings first evolving in arboreal insects. One of the hallmarks of terrestrial arthropod morphology is a marked simplification of those compound limbs, and I would expect to see modified gills being put to other uses if they had survived long enough to follow their bearers into the trees (beetle elytra, the halteres of flies, and other structures clearly derived from wings don't count).
I remember reading a paper some fifteen years ago about stoneflies (order Plecoptera)sculling across the water's surface on cold days with their wings. The authors snipped away various pieces of wing and found the insects could scull quite well with wings that were far too short to allow flight. They suggested that the first flying insects might have evolved from such surface scullers. This is a possibility, even though there isn't much evidence to support it. Thanks to their small mass, the aerodynamic strictures on insect flight are much more lenient than they are for vertebrates. A stiff breeze can carry small wingless insects astonishing distances. It could very well be that vertebrate flight never evolved in non-arboreal animals, but in searching for the first flying insects my instincts would lead me not into the trees, but to the edge of the nearest pond.
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upper: CROWN CROSSING--PARADISE TREE SNAKE & COPPERY FLYINGLIZARD (1990) acrylic 15" x 40"
center: WALLACE'S FLYING FROG (1995) acrylic 11" x 8"
lower: GREAT MINDANAO HORNBILL & RIZAL'S FLYING LIZARD (1997) acrylic 20" x 15"

VANISHING OWLS OF THE WASATCH—PART I

In Utah's Wasatch Mountains, spring is elusive in early April. The other day I was hiking comfortably in a t-shirt at noon—by 2pm it was snowing sideways. The same songbirds I see now have been in evidence all winter, and forget about seeing reptiles or amphibians. Still, a sign appears here and there: blooming Glacier Lilies (Erythronium grandiflorum) poke through the shallow snow on the hills' warm sides, and many of the big birds are thinking seriously about breeding. At dawn the area's small Sage Grouse (Centrocercus urophasianus) population congregates to display on their leks. Turkey Vultures (Cathartes aura), Golden Eagles (Aquila chrysaeotos), Ferruginous Hawks (Buteo regalis) and Prairie Falcons (Falco mexicanus) are all getting amorous. Great Horned Owls (Bubo virginianus), the earliest of all our birds, are mostly well into incubation, and normally their nocturnal breeding calls are replaced this time of year with the eerie wailing of Long-eared Owls (Asio otus), once the commonest large owl of the Wasatch. Roughly two-thirds the size of a Great Horned Owl, the Longear's huge, lanky wings make her look far bigger in the air. A pair of dark-rimmed lemon eyes closely set in the center of a ruddy disk of a face give the bird a permanently flabbergasted look, though her mobile facial feathers and ear tufts give her a range of expressions within the bounds of flabbergastion. Those long ear tufts also disrupt her shape and help her to assume the appearance of her surroundings.

Usually thought of as a forest bird, the Longear is indeed mostly seen in dense trees, where she prefers to sleep and to nest, but at night much of her time is spent in open country. Here in the Wasatch, the birds usually nest in an old Cooper's Hawk (Accipiter cooperi) nest in a dense grove of Bigtooth Maple (Acer grandidentatum) or in a thick Gambel's oak (Quercus gambelii) clone, where an old Black-billed Magpie (Pica hudsonica) nest is usually appropriated. I've never found one nesting in a conifer, but I credit this solely to the difficulty of finding such nests. Three to nine eggs are usually laid in April or May, and incubation begins as soon as the first egg is laid, so the brood always shows a range of ages. The hen sits very tight on the nest, and continually broods the young until they're quite large. If an intruder climbs the nest tree, she usually waits until the last minute to leave. At that point she will call her mate in, and both birds will perform displays of intimidation that are as spectacular as any in the bird world. Longears are often very aggressive; I've been hit and raked by them many times. Perching but a few feet away, they will face their foe with feathers puffed and wings spread and rotated forward so as to present the largest possible surface of avian fury. Swaying to and fro, and emitting a repertoire of hoots, shrieks and demonic wailing that would embarrass Yoko Ono, they are as frightening as a ten-ounce bird can possibly be. Occasionally one will drop to the ground and engage in a broken-wing display, or even pounce into deep grass and produce squeaks like a dying rodent to lure away the threat.

From what I've seen, the birds around here hunt mostly in sagebrush meadows, where they course about at low altitude, searching for voles (Microtus spp.), pocket gophers (Thomomys spp.), and other small mammals in much the same manner as their more diurnal cousins, the Short-eared Owls (A. flammeus). The flight is harrier-like, but even more buoyant, with the body bobbing up and down with each stroke, the wingtips almost appearing to remain level while the body flaps up and down. Like that of many other birds that breed in the Wasatch Mountains, the winter migration of Long-eared Owls is more elevational than geographic. Most of our birds winter in the desert plains to the west, where I am told they feed largely on Desert Cottontails (Sylvilagus nuttallii), a powerful and dangerous prey that more than doubles the owl in weight. I've never seen a Longear kill large quarry, but I assume it's done in the typical owl fashion: the victim clutched firmly with both feet and bill, and the bird hanging on for dear life, in a semi-comatose state until the struggling subsides to the point where the prey can be dispatched. Like Great Gray Owls (Strix nebulosa) and some other species that spend much of the night flying low over fields, Long-eared Owls are very vulnerable to car traffic. While driving across the Nevada desert last September, I counted 27 freshly-killed Longears on a 70-mile stretch of highway.

Sadly, these once common birds seem to have all but vanished from my study area in the Wasatch. Raccoons (Procyon lotor), introduced in the 50s and 60s, have increased in tandem with the human population, and no creature has been hit harder by them than the Longears. In the late 70s I began seeing their nests raided by Raccoons, and within a few years virtually none escaped the masked rascals, which eat the eggs, the young, and even the incubating hens when they can catch them. For a while I worried that I was leading Raccoons to nests, but it seems that A. otus is particularly vulnerable to the carnivores with or without my help. Perhaps there is an attractive scent about the nests.

In the summer of 2004 I found the first successful Longear nest in my study area in 20 years, from which four young birds were successfully fledged. How they evaded the Raccoons is beyond me, but I hope it marks a trend. Last year I was disappointed to find the nest unused. I'm tempted to hike up there tonight to listen for courting owls, but rather than take a chance of disturbing them, I'll wait until late May, after the danger of stressing an incubating owl is over. Once that time comes, a no-holds-barred search for Longear nests will be in order.

In the second half of this post I'll discuss the other local owl that's seen a dramatic decrease in numbers recently, the beautiful little Flammulated Owl (Otus flammeolus).
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illustration: LONG-EARED OWL PORTRAIT (2006) acrylic 15" x 7"

A LITTLE LESS JUMPING AROUND, PLEASE

Back in the days when he was funny, Woody Allen wrote a wonderful essay, A Little Louder, Please, from the point of view of an arts aficionado who feels incomplete because he doesn't “get” pantomime. I never could get dance, and have consequently always felt like a bit of a hollow artistic shell myself. I can appreciate it on the “No way in hell could I ever do that” level, but can't recall ever having been moved by a performance. I can't blame a lack of contact with the art, I live in the dance Mecca of the Intermountain West—Salt Lake City boasts more internationally acclaimed dance companies than I can count on what's left of both hands. I've even dated a couple of dancers in the past, and count a number of them among my close friends. I'm convinced that it's a congenital brain anomaly that I have to accept and learn to live with.

So it was with horror that I opened a letter yesterday from Repertory Dance Theatre, probably the top local modern dance company. This week RDT is premiering a new piece entitled Postcards From Utah. The current members of the company and a number of alumni were each asked to select a painting from the permanent collection of the Springville Museum of Art, and choreograph a dance based on it. Seventeen works by Utah artists were selected, including work by such luminaries as Doug Snow and James Christensen. Also on the list was...gulp...Lizard Relay, by yours truly. I am invited to attend a performance and reception on Friday.

Don't get me wrong, I'm extremely honored that my work was selected, but I simply can't go. I can't imagine how a dance based on that painting could be anything but embarrassing to watch. I'm a naturally curious person, but there are some things that just shouldn't be seen, which is why most of us wear clothes in public. And someone's sure to ask me if I liked it. What would I say then? I'll tell you what I'd say: Nothing. I'd stare into space and stammer. Anyway, I have an excuse—they didn't exactly give me lots of notice, and Friday night the brilliant Australian biologist Tim Flannery will be speaking at the library, just a few blocks away. If you need to get a hold of me that's where I'll be.
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illustration: LIZARD RELAY--JAGUARUNDI, GREEN IGUANAS & BANDED BASILISKS (1991) acrylic 32" x 42"

MORE MUSIC BLATHER

I have no intention of turning this into a music reviewing blog, honest. Still, I just have to mention a little something about last night's show, which delivered perhaps more fun per cubic centimeter than any concert I've seen, even though the club's sound was substandard. I'll keep it brief, I promise. If Gogol Bordello comes to your town and you miss them, hang your head in regret. It's the only appropriate response.
For extra credit, see if you can distinguish between Gogol Bordello violinist Sergey Ryabtzev and Belgian wildlife artist Carl Brenders.