Saturday, May 9, 2009

Smoke and Mirrors II

No names — the guilty, as well as the innocent, are sometimes expedient to protect — but between the many nonprofit organizations that suck up my time, I recently had an opportunity to experience an unpleasant exercise in serial hypocrisy.

I was the hypocrite.

In no particular order, I chatted amiably with a person I detest; bit my tongue when an opportunity to dish on incompetence, with a person who showed every sign of being sympathetic, presented itself; and pretended I wasn’t angry over a situation that was frustrating the hell out of me.

The reason I did all these things was neither an over-active sense of propriety, nor an unwillingness to be confrontational.

You see, I figured I had something to gain.

In each of these situations I walked away with a bit of information I didn’t have earlier; made, hopefully, just the right kind of impression for my purposes; put off a battle for another day, when I could wage it from a position of increased strength.

I have become a game person. I take very little joy in it, but it’s a fact.

That statement probably requires some explanation. A while back I read an essay [1] arguing that there are, essentially, two types of intelligence: puzzle intelligence, and game intelligence. The former is what all us nerds are born with; it is the ability to figure out puzzles, to tease apart the workings of an essentially static system no matter how complex. It’s how you figure out the structure of the DNA molecule, the equations that describe the motion of an object near the speed of light, or how an animal’s sniffer works.

Game intelligence is another thing entirely; it’s the ability to outwit an intelligent opponent in a contest that has no one solution — you have to be adjusting your strategy continually to counter the other player’s. No two contests will be the same, and so the rational faculties that break a puzzle apart, while still useful, aren’t alone sufficient to win.

That, by the way, is the ultimate answer to the wiseass crack, “If you’re so smart, why aren’t you rich?” Fact is, money is a game — and therefore many of the people we see as smart are nevertheless ill-equipped to compete for it [2].

I’m not rich; Lord knows. But I have been able, over the years, to pick up a few pointers on how to face off against game people. I don’t like it; but I need to be able to do it, and so, after a fashion, I’ve learned its ways.

In reflecting on the images I cast — the image in my own mind, the image I attempt to project, and the image received, all of which I know all too well may be very different from each other — I see another connection to enantiomers, those (usually organic) molecules that are chemically identical, but spatially different: non-identical mirror images.

Last time I used a really pretty image that, because I didn’t look at it closely enough, showed two enantiomers but didn’t make it clear that they were mirror images of each other. So let’s try an uglier version, of my own construct, to show the point (again, the dark triangle shows a molecule or chemical group coming out of your screen; the dashed-line triangle shows one going away from you, into the screen):

Although free-solution chemistry can’t really distinguish between the two, an enzyme or other biomolecule, which by definiton reaches out to touch each of these in space, quickly realizes that they’re different:

No matter how you rotate these two, they can’t match up.

Nature has made stunningly complex use of this phenomenon; we’ve already discussed how and why sometimes the olfactory system can tell the difference between enantiomers and sometimes it can’t. Today we’ll discuss a paper by Yuko Ishida and Walter Leal from UC Davis investigating how two closely related species of beetle use enantiomeric pheromones to find the right mate — and avoid the wrong one.

Closely related species, particularly when they’re not separated by a physical barrier like a mountain range or the like, present a major challenge to the evolutionary process. It’s easy keeping a moth from mating with a whale. But two closely related animals — their species separated, perhaps, by specialization to take better advantage of two different food sources — will have a much harder time not inter-breeding, and thus losing the advantage of that specialization. Pheromones — airborne chemical social signals — help keep the two apart.

In the case of the Japanese beetle Popillia japonica and the Osaka beetle Anomala osakana, the two species coexist in nature but don’t inter-breed. Part of the way they’ve accomplished this is that each species has chosen a different enantiomer of the same molecule — either (S)- or (R)-japonilure — as a mating pheromone. (S)-japonilure is a sexual attractant for the Osaka beetle; the (R) enantiomer is an attractant for the Japanese beetle.

It gets even more interesting. The Japanese beetle doesn’t merely “get no kick” from (S)-japonilure; the molecule repels the little buggers. The evolutionary process, then, has double assured that Japanese beetle bachelors don’t hook up with osakana chicks.

Which is where Ishida and Leal’s work comes in. From the antennas of japonica males they’ve isolated an enzyme that chews up both molecules — but it’s measurably better at chewing up the attractant than it is the repellant.

The difference isn’t huge — the half-lives of the attractant and repellant, respectively, in the presence of the enzyme are 30 thousandths of a second versus 90 thousandths of a second. But in the world of olfactory response, that’s a fairly big difference; as our authors note, following an intermittent, turbulent scent plume to its source requires a complex series of decisions based on intensity of smell, wind direction, and attack angle. As dog handlers have noticed and moth researchers have documented, it often takes a lot of dashing, casting, and weaving to home in on the source of a smell. You need to be able to detect changes in your attractant quickly to find its source; and therefore, it’s useful to destroy an attractant as soon as you’ve detected it. Clearing the olfactory palette as quickly as possible leaves you better prepared to detect the next change [3].

The situation is very different for a repellant. You don’t need to find its source; you don’t want to get anywhere near its source. Letting it stick around a little longer is therefore a good thing: it helps stop you, literally, from even going there.

So there we have it: Three species, two games, two sets of smoke and mirrors. One clouds the issues; the other makes them very clear.

I won’t engage in the pseudo-philosophical (let alone exaggerated) species-bashing of comparing nature’s beauty to mankind’s brutality. Evolution itself, I realize, is the biggest game of all. I will play the game as long as I need to. But on the whole, I prefer the puzzles.

[1] Sorry, it’s been way too long and I don’t know where I read it.
[2] Yeah, yeah, they all say they’re not interested in money — but might that not be because they’re not interested in the games that go with it?
[3] There’s an old dog-handlers’ tale out there that dogs’ noses are “so sensitive” that they don’t desensitize like ours do — think of how, after a while in a room with a strong floral scent, you don’t notice it. Well, don’t you believe it: desensitization is a powerful tool for keeping the nose maximally sensitive to changes in an odor. Our dogs couldn’t do without it.

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