Je Ne Sais Quoi

Pity the poor peacock. He can truss himself up in iridescent blues and greens built of billions of intricate, light-catching nanostructures in the feather barbules; he can fan his train of tail feathers that open their hundred eyes to a peahen like an adoring audience; he can coo, bob his head, and shiver so that he positively glimmers like blue bonfire in the forest; and still, the female — who isn’t even that hot — can sniff and walk away. He is the product of millions of years of sexual selection for extravagance, and possesses the most spectacular, show-stopping plumage in the world, but he is far from irresistible. Having seen plenty of peacocks in my life, nowadays I’m more intrigued by the peahens and their discerning gaze. So frustratingly fickle! So charmingly coy! It’s that pickiness that has undoubtedly driven the male to such desperate majesty.

Who hasn’t felt a little like a peacock at times, trying their best to be noticed by the object of their affection and falling short no matter what? What am I doing wrong?, I’ve asked myself. What am I missing? What could she possibly be looking for? I find myself sympathizing with the peacock and his unrequited attempts at winning love on the zoo lawn, coldly rebuffed time after time until he’ll display for any toddler in a pair of brown overalls. Because peacocks look more or less equally fantastic to us, we can’t imagine why a female chooses one and not another. Some guys just don’t have it, the biologists tell us, after a peahen takes a pass on a shimmering fountain of male grandeur. Not wanting to guess the mind of a peahen, they throw up their hands and decline to say what “it” is. That certain something that captures the peahen’s heart. That je ne sais quoi.

Ice cold.

Well, to hell with that! Je veux savoir “quoi”! If the peacock can look like that and still get shot down in flames, unless it possesses that je ne sais quoi, I think I speak for males of all species when I say I sure as hell want to know what the “quoi” is.

Instead of a peacock, let’s talk about its simpler, arachnid analogue, the Peacock Spider. I recently discovered this charming little guy via the famous and fabulous Myrmecos blog, the hot place to be for gorgeous insect photos and bug scuttlebutt. Like its namesake, the Australian peacock spider females are dun and its males garish, with an amazing technicolor dream-abdomen that fans out like a peacock’s tail. Like the bird, the peacock spider male does a display dance for the cautious and picky female, though his involves waving his third pair of legs in the air as if to say, “Hey, baby! Hey! Over here!”

Aqualung

Yesterday’s post was dedicated to spider silk and many of its wondrous uses. Today’s post is about the most wondrous use for spider silk of all. But first, an interlude to talk about comic books.

You know how Spiderman uses his synthetic webbing for all sorts of purposes beyond “slinging”? Sure, there’s the “getting around” webbing, but he can also gift-wrap criminals, or use the “silk” as a projectile glue-bomb that blinds them. He can spin webbing that acts like an airfoil or a parachute. All of these are things that real spiders can do with the seven or eight types of silk for which they’re equipped. But could a spider use his silk to make baseball bats, trampolines, dummies, bandages and slings, or even watertight domes that would trap air so that he could breathe underwater?

Yeah, about that last one.

Web Design

A friend recently asked me about what to do about the black widow that was spinning a web over her entire sliding glass back door. (When you are the naturalist among your friends, you tend to get a lot of extermination questions.) To be perfectly frank, I hate spiders. Whenever I make the conscious choice not to squash a spider on sight, I give myself a little mental cookie, much the way I do when I put an aluminum can in the recycling bin. Call it the Indiana Jones principle: You’re allowed to be creeped out by one type of animal. I don’t understand some people’s fear of snakes, but I can respect tolerate it. I know some bad-ass people who are afraid of rats. I love most animals. Just not spiders.

But I do love a well-spun spiderweb. A dew-dappled spiderweb early in the morning is a thing of supreme beauty, and the silk itself is an awe-inspiring substance. Normal spider silk has the tensile strength of steel, while the silk of the Darwin’s Bark Spider is ten times stronger than Kevlar. Most silk lines are only a few microns across, but if a spider could weave a strand the width of a pencil, that strand could conceivably stop a Boeing 747 in mid-flight. What’s more, spiders are capable of weaving up to 8 different kinds of silk from its spinneret glands: silk for draglines, silk for wrapping egg sacs, silk for wrapping prey, silk for parachutes, etc. And not every web is the classic “spiral orb;” webs are also designed as tubes, funnels, tangles, sheets, and domes.

However, the spider I want to focus on today is an orb-weaver, the Australian St. Andrew’s Cross spider, pictured above. Members of the Argiope family, such as the St. Andrew’s Cross, are often called “garden spiders,” or “writing spiders,” on account of their habit of decorating their webs with flourishes that sometimes resemble language. The name for these decorative markings are stabilimenta.

Argiope aurantia. Don’t read too much into it.

At first glance, the “X” shaped stabilimentum of the St. Andrew’s Cross spider seems to have an obvious purpose: the make the spider’s silhouette less obvious to both predators and prey. But stabilimenta take many forms and shapes with spiders all over the world, and the reasons for them are legion, varied, and mysterious.

Land of the Lost

The other day we discussed adaptive radiation, the process by which a single ancestor can split into an aardvark, an elephant, a manatee and a mole. But how do species split from one another? Usually by being physically separated for a good amount of time. The obvious illustration would be a species radiating between islands, but “islands” can occur on land, too. Even within islands.

Rodents Of Unusual Size? I don’t think they… oh, there’s one.

Meet the Bosavi Woolly Rat, a cuddly cat-sized rodent and the largest rat in the world. What makes it remarkable isn’t just its size, but its location. It was discovered only last year in the Bosavi volcanic crater in Papua New Guinea, along with at least 40 other amazing animal species heretofore unknown to science and native only to this one crater, including a fanged frog, a fish that “grunts,” a marsupial called the Bosavi silky cuscus, a tree kangaroo, a new family of sleestaks, an ogre-faced spider that fishes for its prey, a new species of bat, the world’s smallest parrot, a new bird-of-paradise and caterpillars that collaborate to look like a snake. These creatures had no fear of humans, having probably never seen one before. After all, they’ve been walled inside an extinct volcano for 200,000 years.

The Mystery of the Glow-In-The-Dark Scorpion

Here is a biological riddle that’s been fascinating me lately. While scorpions are not a “rare” animal, per se, they possess a trait that has yet to be fully explained by evolutionary science: they glow under ultraviolet light.

This isn’t bioluminescence. They are not generating their own light. Only under a source of ultraviolet, like a blacklight, do they show their true colors. But scorpions are nocturnal and stay out of the sun… and raves in the desert, while apparently not uncommon, aren’t exactly natural. So why would scorpions evolve the ability to glow when they don’t seem to use it? After the jump, some hypotheses, and why they are probably wrong.

The Spider That Plays The Guitar

Part III of the Rock and Roll series: This one is for guitarists and vocalists. The subject: AMPLIFICATION.

Africa’s Namib Desert is one of the harshest and most unforgiving environments on Earth. Located off the aptly-named Skeleton Coast, it has the lowest annual rainfall of any place besides Antarctica. If you were shipwrecked there, you wouldn’t find drinkable water, but every morning you’d be treated to a tantalizing fog that rolls in from the ocean and quickly evaporates in the hot desert wind.

Because of the wind and the fog, it’s useless for native spiders to spin webs. So the Corolla Spider has a different strategy. It makes a burrow, and surrounds it with quartz pebbles.