Orchids

August 30, 2009 10:24 AM

How do you spread your genes around when you're stuck in one place? By tricking animals, including us, into falling in love. Orchids — Love and Lies

Orchids are dizzying in their diversity. Over the past 80 million years, some 25,000 wild species have taken root on six continents, in nearly every kind of habitat. Representing a full fourth of the world's flowering plants, there are four times as many orchid species as mammals, and twice as many as birds.

Perhaps the most clever deceit of all is offered by those orchids that hold out the promise of sex. And not exactly normal sex. Really weird sex, in fact. I went in search of one of the most ingenious and diabolical of orchids: the Ophrys. (Some botanists call it the "prostitute orchid.") I'd been eager to lay eyes on this orchid and meet its hapless pollinator ever since reading about its reproductive strategy, which involves what my field guide referred to as "sexual deception" and "pseudocopulation."

The pollination strategy of the Ophrys is, like that of so many orchids, ingenious, intricate, wily, and seemingly improbable—so much so that proponents of intelligent design sometimes point to orchids as proof that the hand of a higher intelligence must be at work in nature. (And a rather sadistic intelligence at that.) Yet the peculiarities of orchid sex actually offer one of the great case studies of natural selection, as Charles Darwin himself under­stood. Darwin was fascinated by orchid pollination strategies, and though he was puzzled by the purpose of Ophrys's uncanny resemblance to bees (pseudocopulation wasn't observed until 1916), he taught us much of what we know about these plants in The Various Contrivances by Which Orchids are Fertilised by Insects, the volume he published immediately after The Origin of Species.

Outcrossing, or mixing one's genes with distant mates, increases vigor and variation in one's offspring, maximizing fitness. The sexual frustration of a deluded bee turns out to be an essential part of the orchid's reproductive strategy. Determined not to make the same mistake again, the bee travels some distance and, if things work out for the orchid, ends up pseudocopulating (and leaving his package of pollen) with an orchid a ways off. That distant orchid is likely to look and smell ever so slightly different from the first, and some botanists believe these subtle variations from plant to plant are part of the orchid's strategy to prevent bees from learning not to fall for a flower. "Imperfect floral mimicry" [pdf] is the botanical term for this adaptation.

There's a video on YouTube, a riveting snippet of interspecies porn, in which you can watch a wasp be utterly bamboozled, and then humiliated, by an Australian tongue orchid. The tongue orchid (Cryptostylis) lures its pollinator by deploying a scent closely resembling the pheromone of the female wasp.

"Prurient apparitions," is how Victorian critic John Ruskin described these flowers. Prurient? Is it possible that humans can look at an orchid and, like the deluded orchid bees or male dupe wasps, see an apparition of female anatomy? (Georgia O'Keeffe certainly did.) Could it be that plant sex and animal sex have gotten their wires crossed in human brains just as they have among the bugs? That accident of evolution has proved another happy one for the orchid, for look how much we humans now do for these flowers: the prices paid, the risks to life and limb endured, the pains taken …

posted by netbros (15 comments total)

How do you maximize ads on your site while pissing off visitors? By spreading an article out unnecessarily over multiple pages. Shame on you, National Geographic.
posted by GavinR at 10:29 AM on August 30 [1 favorite has favorites]

Sorry GavinR. Here is the print version.
posted by netbros at 10:51 AM on August 30

What a fascinating article. Natural selection FTW!
posted by darkstar at 10:58 AM on August 30

netbros, Goergia O'Keefe always denied her paintings were related to sexual anatomy. It apparently irritated her that people thought so. However, artists aren't always completely objective about their work, and practically everyone else thinks there was a definite visual correlation.

Love this post, though. Thanks!
posted by annsunny at 11:31 AM on August 30

Adaptation
posted by inconsequentialist at 11:57 AM on August 30 [1 favorite has favorites]

How do you spread your genes around when you're stuck in one place?

I run a mail-order subscription service. Do you want my catalog?
posted by DU at 12:04 PM on August 30 [1 favorite has favorites]

By tricking animals, including us, into falling in love.

Or failing that, getting high.
posted by weapons-grade pandemonium at 1:13 PM on August 30

Orchids have nowhere near the mind altering exploitive darwinian fu of lawn grass.
posted by srboisvert at 1:45 PM on August 30

Attenborough's great "The Private Life of Plants" has an episode on this stuff, called "Flowering." Youtube playlist (part 4 starts in the middle of the Orchid section)
posted by smackfu at 2:08 PM on August 30

I thought that was a brilliant article. As I read it, questions/objections came to mind which were subsequently addressed on the next page.

I'm usually annoyed by the 'article spread out over multiple pages to increase page views' model... and yet I'm also really worried about the loss of articles such as this altogether, because publications can't retain a viable business model.

That aside, I had to keep reminding myself that there weren't species of bees flying about in a world without orchids, until some conniving seductress of a flower came along and produced a fake female bee behind to tempt them. They evolved in tandem.

We really should be teaching "the orchids and the bees" alongside the "birds and the bees".
posted by vectr at 2:53 PM on August 30 [1 favorite has favorites]

netbros: Yet the peculiarities of orchid sex actually offer one of the great case studies of natural selection, as Charles Darwin himself under­stood. Darwin was fascinated by orchid pollination strategies

In addition to the stated example, Darwin famously found an orchid which he postulated (in the above mentioned book) to be pollinated by a moth, and more interestingly, one with a proboscis between 12 and 16 inches long, though no such moth had been found.

The idea was ridiculed for over 40 years, until, 20 years after his death, Darwin was proven to be precisely correct, when the corresponding moth was found, and shown to, indeed, polinate the orchids.

Wiki article on the same.
posted by paisley henosis at 7:02 PM on August 30

I'm not sure I appreciate the leap from insects being fooled into assisting with pollination (something that many plants do, not just orchids) to humans behaviour. Sure, orchids are pretty and interesting, and so will hold our attention, but this is different than evolving some sort of interspecies relationship with them. There is a world of difference there.

in which you can watch a wasp be utterly bamboozled, and then humiliated, by an Australian tongue orchid

This sort of lazy direction always rubs me the wrong way. Observe some behaviour; describe the behaviour in human terms (wasps are "bamboozled" and "humiliated"); leap from that to a direct parallel human behaviour with no other evidence other than the pattern appears to match when you hold it up to the light.

And whenever I see this trend, I worry that the writer is having the tail wag the dog. It becomes too much of a just-so story.

Humans (and perhaps other primates) have a tremendous capacity for symbolic and complex thinking about the world, which includes how we understand and appreciate things like pretty flowers. They remind us of /things/, sure. But are those reminders some sort of genetic predisposition, or is it a culture-driven piece of the human mosaic? Do we know a little how other cultures feel about these same flowers, and through all time? Has human behaviour been altered by the flower, or by complex interactions of cultural expressions?

It seems to me that, while human activity has increased the potential for many species of orchid (as it has for many species of gazelle), there are many other species that are endangered or have died out completely. Either the effect some orchids have on us is limited or, like some types of food animals, we have deliberately chosen some species for our own complex reasons, leaving the rest to the hobbyists and environmentalists.

This stuff /is/ fascinating, of course. How evolution allows these sorts of complex and interrelated behaviours to emerge is, too me, why I have stayed interested in science all my life. Trying to figure this stuff out is what gets some folks out of bed in the morning. I just feel that reducing these stories into some what-ifs about the human condition does us, and science, a disservice.

Humans are a little more complicated than that, and this is why we have thins like anthropology and sociology.
posted by clvrmnky at 6:28 AM on August 31 [1 favorite has favorites]

paisley henosis, thanks for drawing attention to the Angraecum sesquipedalia and the pollinating moth that Darwin predicted ... the angraecoids are among one of my favorite genuses of orchids, and include some of the most enchanting of the "aromatic" orchids. Scent is one of the other devices that orchids have developed for attracting pollinators, though some less savory than others...to wit, some such Bulbophyllum phalaenopsis.
posted by aldus_manutius at 11:24 AM on August 31

Humans are a little more complicated than that, and this is why we have thins like anthropology and sociology.

Agreed, but domesticated cats being one counterexample.
posted by darkstar at 11:35 AM on August 31

Where Did All the Flowers Come From?
posted by homunculus at 2:45 PM on September 8