Cryptic, calculating and coveted, orchids embody the artistry of evolution, and outwit intelligent orders of life at every turn.
She was at first just awhiff of intoxicating scent. But as he turned and followed, the hint of her billowed into a beacon of congress. He zeroed in on her perfume, and now, awash with pheromones, catches his first glimpse of the siren: lustrous and opulent in the dappled light. Open, susceptive, her voluptuous form is invitation incarnate.
He’s inexperienced (a virgin, in fact), and fumbles in his ardour, but she’s had a legion of lovers. She guides him inexorably to her cloven essence, and he falls into her. Though she is the apple of his compound eye, he has been deceived. Her folds embrace him. Whatever he expected of sex, it is not realised in this treacherous chamber. Steep and lubricious, it thwarts his every foothold. That heady perfume is now a miasma. Compelled still now by lust, he thrashes and fumbles, but where seconds ago was the fetching form of his own species, there is now a hydra. Uncountable arms push him further down, into darkness and delirium.
Then, above, a faint glow of escape: deliverance to the light of day. A column offers firmer footing, and he clambers for the exit. Sodden with her dankness, exhausted and caked in dust, he can barely fly well enough to flee this den of guile.
They both sought sexual fulfilment, but only she got it. She is an orchid, and her kind has endured for millennia by overpromising and underdelivering. The bewildered bee is now a courier for her pollen, daubed by a spring-loaded device that attached a pair of yellow pollinia to his back as he clambered free. The orchid knows his lust will prevail over any memory or learning. Soon, he will fall again for the same deception, and his fumbling will deliver her pollen to a suitor of her own, unknown and—importantly—distant.
Sexual commerce may be the oldest human profession, but orchids were trading in it at least 20 million years ago. An extinct species of stingless bee, found trapped in Miocene amber in the Dominican Republic in 2007, still bore the pollen of a previously unknown orchid on its wings.
By calibrating genetic mutations, researchers were able to turn the orchid’s evolutionary clock back, and concluded that orchids may have arisen between 76 and 84 million years ago, during the Late Cretaceous. In other words, they risked trampling by dinosaurs. Subsequent studies have suggested the Orchidaceae hark back still further, to 100 million years ago. That’s one of the most comprehensive programmes of continuous development in the plant world, so it’s little wonder that orchids prevail today as one of the largest families of flowering plants.
Botanists recognise between 21,950 and 26,049 species in 880 genera, and add some 250 new species every year. Orchids occupy every terrestrial habitat except glaciers, which is not to say they resile from cold—they venture beyond the Arctic Circle, south to deepest Patagonia, and have even colonised subantarctic islands—but the tropics are their hotbed. In the rainforests of Central America, West Africa and tropical Asia, heat, humidity and humus have fuelled orchid evolution to hallucinogenic extravagance.
Orchids are considered the most advanced and diverse flowering family. Like the Detroit automakers of the sixties, evolution seems to be piling embellishment upon adornment out of sheer creative exuberance, except that orchids are also breathtakingly functional.
The essence of orchidity is the flower: it must have three petals and three sepals, but that basic apomorphy finds thousands of fantastical expressions. The third petal, called the labellum or lip, is always the most modified, to make a platform for pollinators, a clue to the ancient compact between insects and orchids.
After insects evolved winged flight around 330 million years ago, plants everywhere seized the opportunity to get them to perform their sexual errands.
Dozens of families evolved bright flowers as billboards enticing insects to their nectar, and while orchids took the strategy to its most beautiful embodiment, fully a third opted for a life of fraud.
Saving themselves the energetic expense of nectar, they have instead poured their resources into elaborate visual, olfactory and tactile deceptions. Some simply mimic a real nectar-bearing species. Others, like the Dracula orchid, lure dung-eating gnats with synthesised stench: they can broadcast the smell of faeces, urine and rotting meat.
Some orchids’ flowers, like those of the bucket orchid at the start of our story, are pollen-loaded mazes. Others are unsprung traps: when bees land on a male Catasetum orchid, they trip a trigger that whacks them on the head, leaving a bundle of pollen attached. Dazed, the bees retreat into the nearest shelter—the Catasetum’s female flowers, which closely resemble the bees’ own nests.
Others have taken the female form of particular insects (one has perfected the illusion of the rear end of a female bee projecting from its own flower). The Australian hammer orchid is such a dead ringer for a female thynnid wasp that duped males will even ejaculate over its flowers—a gaffe called pseudocopulation—and get dusted with pollen while doing so. But the benefits of such mimicry are still more strategic: female thynnid wasps can reproduce asexually, and always produce males when they do. So when males exhaust their sperm on a flower, more female wasps are forced to breed asexually. The result? More males produced, and more pollinators for the hammer orchid.
Some doppelgangers are so convincing that they can goad insects into attacking them. Oncidium orchids so resemble the rivals of territorial bees that when the outraged insects head-butt the fake antagonist, they’re dusted with pollen.
Only lately discovered on a remote New Britain island in Papua New Guinea, Bulbophyllum nocturnum is the only orchid known to flower solely in darkness, and only over a single night: by the next morning, the strange, glutinous-looking flowers have withered. What pollinator could the orchid possibly be courting in the watches of the night? That mucilaginous bloom offers a clue: it’s a dead ringer for slime mould, the favourite food of night-flying tropical midges.
But B. nocturnum at least honours its part of the deal, offering nectar to the midges because, researchers think, only blossoming for a single night, it can’t afford to try welching out. Sexual deception can be a hit-and-miss strategy for the orchid. Natural selection rarely rewards undue complexity, so just why so many orchids practise such elaborate—and costly—mimicry and mechanics, when they could simply play it straight with nectar rewards, has evolutionary biologists scratching their heads. And why doesn’t evolution punish all those addled insects that keep trying to mate with a plant?
To address the question, botanists added nectar to a nectarless orchid. Insect pollinators, instead of fleeing the scene of their frustration and abuse, lingered around the artificially sweetened plants, checking out bloom after bloom. But this is the last thing the orchid wants, because it dramatically raises the risk of inbreeding, which produces weaker seeds. By roughing up its hapless pollinators, the orchid actually encourages them to head for the hills, where they eventually, hopefully, deliver the orchid’s DNA to a distant—geographically and genetically—mate.
Keeping a safe genetic distance promotes vigour and resilience. Critically, it is also the stuff of subtle variation: if each orchid—even those of the same species—looks vaguely different to a bee, it’s less likely to tumble the orchid’s game, and will go on playing the unwitting pollinator. It’s called imperfect floral mimicry, and as science writer Michael Pollan put it: “The very imperfection of the orchid’s mimicry may itself be part of the perfection of its reproductive strategy.”
As for the insects that waste time, energy and, occasionally, sperm trying to copulate with a fake, it’s been suggested that their strategy of promiscuity might just be the more genetically successful, especially if you’re short-lived. Immortality through immorality, so to speak.
Nectar is costly to make, and craved by so many creatures that a generalist flower may be visited by moths, ants, bees, birds, possums and bats in the course of a single day. That’s a haphazard way to deliver your pollen to the right target. Many orchids have taken the other route, each species courting its own specific pollinator with exacting mechanisms that exclude any other forager (see sidebar). It ensures the pollinator’s next call will very likely be to one of their own kind.
Botanists suggest this may explain the orchids’ lavish diversity: many attract pollinators by manufacturing a scent explicitly tuned to the senses of a particular insect. Should a mutation alter that
scent even slightly, an orchid could lose the interest of the original pollinator, while attracting a new one, in which case the plant’s physiology would begin evolving anew to attract, trap and pollinate the new courier. The hypothesis is backed by the multitude of orchids that look superficially similar, yet differ genetically—albeit subtly.
For all their miscellany, though, most orchids are by no means abundant. That very scarcity, say botanists, ensures their survival. Their deception works only because insects are accustomed to getting rewards of pollen from honest plants, which are much more common in the landscape. Cheats can prosper only when honesty prevails—if insects were more routinely duped, they’d soon give up.
So the ploy is a risky one, but it works. Besides, orchids have hedged their bets in seed dispersal as well. Each pollinium holds thousands of pollen grains, and the resulting seed pods in turn contain thousands of seeds each. But once broadcast, the orchid again abrogates its responsibilities. The seeds are practically a token: pared to the essentials, they don’t even offer sustenance to a developing embryo. If seedlings are to survive, they need the help of an endophytic fungus, which delivers nutrients to the seed through probing tendrils, another hit-or-miss orchid strategy that relies on the kindness of strangers. Indeed, one might wonder just how orchids survived and thrived for so long.
We know from the only fossilised orchid ever found in the southern hemisphere that they were growing in New Zealand at least 21 million years ago, but they were not, says the Department of Conservation’s principal science adviser on threatened plants, Peter de Lange, original passengers on the drifting Aotearoa. “Our orchid flora is derived entirely from bits that blew here from Australia,” he says. “People will want to kill me for saying it, but floristically, we’re very much the Antipodean poor brother.”
That said, there are at least 120 species here, and perhaps as many as 400, depending on who you ask. Thirty-five genera—spider orchids, sun orchids, helmet, duck and onion and potato orchids, to name a few—have colonised the country pretty much from the high-tide mark to the subalpine tops. You’ll find them in beech and broadleaf forests, scrubland, swamps and montane herb-fields. Some frequent roadsides, clogged gutters or even your lawn—though only where the soil is poor and boggy. Oddly, in a world where fully two-thirds of orchids are either epiphytic (growing on other plants) or lithophytic (growing on bare rock), New Zealand has just eight epiphytes.
Whatever their lifestyle, don’t go looking for any flamboyant femmes fatales in your patch of local bush: our orchids are mostly wallflowers. Like so much of our biota, many are visually unremarkable: small (one species sports blooms just three millimetres across) and often nondescript, they’re so cryptic that you’ve walked right past more orchids than you ever knew existed.
“It’s because it’s so boring,” says de Lange, “that our orchid flora is actually incredibly exciting. That’s the paradox.” The marvel of our orchids is that they’re here at all: blown (or carried on the feet or feathers of birds) as seeds from Australia, their ancestors first had to literally land on the right fungi to germinate, then things got really tough. “If you come from a country where there’s a whole host of specialised pollinators,” says de Lange, “then you sail across the oblivion and land on an island where you’ve got a depauperate and generalist invertebrate fauna, then having a really specialised strategy to get yourself pollinated is simply a fast track to extinction.”
So began a race against senescence: the pioneer seedlings had to find a way to reproduce without the aid of their insect lackeys. When de Lange started at DOC in 1990, the first thing he did was take a look through the list of threatened native orchids. While plenty were listed as endangered or even extinct, he soon realised that not one of them was endemic. “Every single one of them was abundant in Australia. All of them had specific pollination requirements in Australia, and none of those pollinators were to be found here.” He declared them vagrants.
“If there’s no other way to transmit your gametes around, and nobody to cross with, you’re dead,” says de Lange, “unless you can fertilise yourself, or cross with a distant relative, and that’s exactly what our orchid flora has done.”
The defining feature of our orchids, then, “is the loss of reproductive specialisation, and when you think about it, that was the right thing to do. There’s not one endemic orchid in New Zealand that is genuinely threatened. All of them are either self-pollinating or have a generalist pollinator, so they set abundant seed irrespective.”
Other species have been successful: Cryptostylis subulata, commonly called the duckbill orchid, has colonised Far North swamps, but endured only because its specific pollinator, a wasp, had already arrived here. “When Cryptostylis arrived, the wasp found it,” says de Lange.
The Thelymitra sun orchids, on the other hand, gained a toehold wave by invasive wave. “Out of each wave,” he explains, “some plants became reproductively selfing, and have been very successful, then subsequent waves hybridised with those.”
No such deliverance for the nodding greenhood orchid, Pterostylis nutans, now confined to a single known colony near Taupo. While it’s a gymnastic self-pollinator, it nevertheless faces nihility unless its insect pollinator somehow shows up from Australia. “It’ll eventually exhaust its habitat and die out,” predicts de Lange. In fact, P.nutans has had several previous goes at immigration, but was thwarted by human nature. It was first discovered by Henry Matthews at Pukemiro Hill, near Kaitaia, in 1914. Matthews was an avid orchid collector and filled tray after museum tray of specimens—some grace Te Papa even now—until sometime around 1920, when he could find no more. He’d collected nutans—as well as two other species—to local extinction.
That sort of covetous stockpiling, says de Lange, still goes on. “Some of our orchids are very beautiful—the bearded orchids, for example—and we’re very careful not to disclose their locations, because our experience is that the moment people know where they are, some idiot will collect them. I’ve been to car-boot sales where I’ve seen a car boot full of orchids, and the person would insist that they’d grown them, but I knew that they hadn’t. In some cases, I could pretty well match exactly where they’d come from. When you dig one up, you’re not only depriving other people of the pleasure of seeing it, but you’re wasting that orchid and your time, because they’re impossible to grow.”
Bird orchids, Simpliglottis valida, bloom in the Iwitahi native orchid reserve on the Napier–Taupo Highway. Iwitahi was declared a heritage protection area in 1987, after several rare native orchids were found thriving in the acid soils of the plantation forest.
Like so many things scarce and beautiful, orchids seem to bring out the worst in some people. In 2004, two Czech collectors, Jindrich Smitak and Cestmir Cihalik, were stopped trying to smuggle native orchids out of the country. Smitak was an inspector in the Czech Environmental Inspection Agency and then-chairman of the Society of Tropical Orchid Growers and of the Friends of European Wild Orchids. Cihalik, a cardiologist, was dean of medicine at Palacky University of Olomouc. They had poached more than 100 plants from Fiordland, Mt Aspiring and Nelson Lakes National Parks, all the while under the clandestine surveillance of the Wildlife Enforcement Group.
The Victorians called such madness ‘orchidelirium’ after collecting, theft and taxonomic appropriation hit fever pitch in the 19th century.
The gentry put a price on orchids’ heads, dispatching collectors to every corner of the globe for new acquisitions, all the while spreading misinformation about their destinations to throw rivals off the scent.
Orchids began fetching ridiculous prices in London auction houses, even though almost no-one knew how to keep them alive, let alone cultivate them—survival rates were negligible.
Even today, orchids’ bewitching beauty, their guile and their suggestive resemblances (‘orchis’ is ancient Greek for ‘testicle’) ensure a cult following that “borders on the rabid”, says de Lange. “The orchid is still used in medicines believed to evoke sexual desire and treat impotence.”
So fickle—almost perverse are orchids’ evolutionary strategies that, even when we’re trying to conserve them, we can still get it wrong. Corybas carsei, the swamp helmet orchid, is perhaps our rarest, known from just one location in the Whangamarino wetland in Waikato. It was presumed extinct until the early 1980s, when it was rediscovered during a survey gathering evidence against proposals to drain part of the wetland.
“It was a massive moment for taxonomy,” recalls de Lange, “because it confirmed that this thing was different—distinct from the Australian species it had been lumped with previously—but also because they found lots of it.”
When de Lange went back to the area a decade later, the swamp helmet orchid had vanished once more, even though its haunts had since been protected. “The entire habitat had changed completely.” Then, a local farmer told de Lange that in the past, sparks from the old steam trains on the main trunk line would frequently set fire to the swamp. “The fires would rage for months. Nobody put them out in those days, because nobody cared less about wetlands.”
Once the wetland came under protection, DOC immediately doused any fires, says de Lange, “Because we believed our flora was not adapted to it.” But in time, he came to understand that periodic conflagrations weren’t just a fact of wetland life, they were essential to it. “So we wanted to burn this wetland, to see if we could get the orchid to come back.”
It was a radical plan—“people thought we were nutters”—but he eventually got permission for a few small, localised winter burns. By spring, the swamp helmet orchid was back, and a winter burn every seven years is now central to its management plan. “The wetland is continuing to go the way it should,” says de Lange. In 2008, a search of Whangamarino found 79 swamp helmet orchids; in 2011, DOC counted more than 200.
Orchids may look dainty, but they’re tough and calculating, and they’ve been this way for a very long time. If we’re serious about helping them to flourish, says de Lange, we have to learn how to manage the dynamic, successional habitat most of them prefer. We have to foster contingency, and embrace chaos, as they do.
“We’re failing, and that’s actually the biggest threat, not only to our orchids, but to most of our threatened flora, because much of it occupies successional habitats.” That demands a departure from the conventional mantra of pest eradication until pristine: we have to first determine, and then accept, an acceptable level of exoticism if we’re to safeguard successional diversity.
No orchid better illustrates that concept than another recent discovery, originally thought to be Taeniophyllum norfolkianum, a mundane, leafless epiphyte—scarce even on its native Norfolk Island that resembles, according to de Lange, “a lump of green spaghetti thrown against a wall”. It’s known only from one patch of scrub near Waipu in Northland, and while much of that patch is native vegetation, the orchid has been found living only on gorse.
De Lange is convinced, in fact, that the plant isn’t norfolkianum. It may be yet another new arrival (and potentially a viable one, if its weedy gorse habitat is left alone), or possibly even endemic. Either way, he says, “we’ve looked and looked elsewhere, and we haven’t found it. So is this thing truly tied to gorse? If so, then surely it’s come from somewhere else. Or is it that it’s simply so cryptic that we haven’t spotted it on another host? We really don’t know, but at the moment, the only known population grows only on gorse.”
The confusion around this new immigrant’s true identity highlights another critical issue in orchid conservation: we have only a sketchy idea of what lives here. “New Zealand has very few biosystematists left,” says de Lange. “I’m 46, and I’m one of the young ones. The biggest research priority is actually defining the problem, and to define the problem, we need to know what we’ve got in the way of orchid diversity.”
The very mutability of orchids only makes things worse. The threatened-plants lists, he says, are full of orchids awaiting taxonomic determination. Until then, “they’re hypothetical possibilities, pending taxonomic projects. Many were listed in the 80s, and they’re still sitting there, waiting for a name. Until we have confidence about what we’ve got, we can’t really sort out what the conservation priorities should be.”
In the crisp dry air of a Te Papa storage room, Carlos Lehnebach shoulders an enormous rolling cabinet aside and opens a cardboard box so anodyne you’d never guess its priceless contents. “These are the first orchids collected from New Zealand,” he says, matter-of-factly, “the type specimens from which the first few species were named.” In elegant Georgian script—Swedish naturalist Daniel Solander’s own hand—is a label: Ichthyostomum pygmaeum. The tiny three-millimetre flowers, collected during James Cook’s first voyage in 1769, are now just brown granules, but, says Lehnebach, a few other specimens still show the faintest hint of colour.
He doesn’t think New Zealand orchids are remotely boring: in fact, they’ve so captivated him that he moved here from his native Chile to try to unravel the tangle that is the spider orchids. Endemic, but with relatives in tropical Asia, they can reproduce vegetatively by sprouting runners but, critically, cannot self-pollinate. That means they need the help of an insect. Lehnebach has assembled a body of evidence that points to the fungus gnat, the winged adult of the glow-worm. His special interest is in Nematoceras trilobum, and he’s found it clustered near cave entrances, but the smoking gun is the eggs and larvae of fungus gnats found on the orchid’s flowers. The female gnats, he believes, have been suckered into laying their eggs on the flower (which contains no sustenance for the gnats’ larvae) because it resembles the fruiting bodies of the fungus they would more properly visit, right down to filamentous tubules that look like fungal threads. He’s also investigating the possibility that the fraud is the more convincing for a scent that replicates the fungus’s.
But if fungus gnats are indeed Nematoceras’s flunkies, the strategy seems to be a flawed one. “The fruit set in these orchids is very low,” says Lehnebach. “In a system that is working well, you might see 70 per cent fruit set. But go to any spider orchid population, and you may see as little as one per cent that’s been successfully pollinated.”
One reason, he says, could be that, as pollinators, fungus gnats simply aren’t very efficient, or not very abundant. “Fungus gnats are good biological indicators, and they may be signalling that there’s something else wrong with the ecosystem.”
Or it could be that the spider orchids, like so many others, arrived here without their customised pollinators, and found good help hard to get. Perhaps they’re simply trying to manage as best they can. The relationship certainly lacks the elegant harmony of so many others: he’s found a number of gnats dead, trapped in a narrow tunnel in the orchids’ flowers. “Killing your pollinator isn’t a very good strategy,” says Lehnebach. “We may be looking at a maladaptation.”
Spider orchids are bafflingly mercurial: Lehnebach has found a medley of subtly different forms, in colours ranging from yellow to purple, some of them very rare and localised. Could they represent a family of discrete species? If so, he says, it will have implications for their conservation. “The other interesting thing is that many of these forms are sympatric: they’re found in close proximity to one another. So, if they’re different species, what’s preventing them from hybridising?” Initial examination shows that chromosome counts differ, but there’s also evidence of some gene flow between the plants. And, wonders Lehnebach, “are they each using a different species of fungus gnat as a pollinator?”
Then there’s the vexing reliance on fungi for germination. Does each orchid form a unique relationship with a corresponding fungus? The answer could be very important, because without an understanding of this complex and potentially exclusive relationship, there’s no way to conserve the species outside their natural environment. “If we could raise endangered species from seed, that would take some pressure off them,” says Lehnebach. “At the moment, all DOC can do is monitor those populations.”
The orchids’ high-risk game plan has worked—mostly for millennia, mainly because of their boggling sophistry. Playing with nothing more than chemicals and blind natural selection, they’ve gambled on eternity with raffish verve. Along the way, they’ve hoodwinked a host of organisms into doing their bidding.
The passion of ‘orchid people’ only goes to show that orchids have got us working for them too.