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Spec Tech: In Darwin’s Footsteps

February 3, 2011

Over the years, I have contributed to several anthologies that ape the form of a scientific compendium. The first of these, and one that undoubtedly influenced subsequent anthologies of a similar nature, was THE THACKERY T. LAMBSHEAD POCKET GUIDE TO ECCENTRIC AND DISCREDITED DISEASES, edited by Jeff VanderMeer and Mark Roberts. More recently I contributed to THE FIELD GUIDE TO SURREAL BOTANY, edited by Janet Chui & Jason Erik Lundberg, which has the distinction of actually being reviewed by the august scientific journal SCIENCE.

What I thought I would do here is go through my piece from THE FIELD GUIDE, but this time add footnotes so that the scientific basis for the piece becomes apparent.  The take-home message, if there is one, is something that I once read, namely that the field of study most useful to a science fiction writer is not in fact science, but history. Here it is the history of science and of Darwin’s research in particular that provides the loam from which this flower grows.

Common name: Queen Victoria’s Bloomers (1), Monkey Ho

Systematic name: Caligulus homocopulus (2)

Appearance:

The first recorded description of C. homocopulus comes from Charles Darwin who, in 1862, published the book, “On the Various Contrivances by which British and Foreign Orchids are Fertilized by Insects.”(3) Unfortunately, due to the mores of the time, this was an expurgated text and some of the Darwin’s most interesting observations were confined to an appendix available only by subscription to men over the age of 30. It is here that we find the following description:

“Although dried, pressed, and sectioned into various folios at the Royal Herbarium and thus lacking the intense color and unrivaled immediacy of the bloom in situ, I do not hesitate in declaring this orchid the King or rather the Queen of flora. I have measured the dimensions of the reassembled bloom and find it to be three-feet nine-inches in width and fully five-feet four-inches in height! In color it is of a deep reddish purple, the two outer petals edged with a fringe such as one might find on a curtain. But it is not the size or the color of the flower that must most excite the admiration of travelers in Madagascar, it is rather the perfect mimicry exhibited by the orchid labellum to the lower torso of a human female. Discretion forbids my dwelling overmuch on this aspect of the flower, but the reader can be assured that this mimicry is exact down to the smallest detail. The appearance of this bloom, and possibly the excitement attendant upon discovering it in the jungle, calls to my mind what a young man experiences on his wedding night as he draws near his bride in her canopied bed.”(4)

Ecology:

Historically, the natural habitat of C. homocopulus is the tropical broadleaf forests along the eastern coastal strip of Madagascar, and extends to an elevation of 1000 meters in the subhumid highland forests. Deforestation has severely impacted its habitat, however, and greater numbers of the species are now found in collections than in the rain forest. (5)

Life cycle:

C. homocopulus is a perennial, flowering once a year, with the flower persisting until pollinated after which it rapidly senesces. Darwin hypothesized that the “pseudomimicry” exhibited by the flower played an important role in the life cycle of the plant, luring animal pollinators to the orchid by sexual deception. Darwin predicted that the pollinator was a large lemur, and declared that “naturalists who visit Madagascar should search for this primate with as much confidence as astronomers search for the planet Neptune, and I venture they will be equally successful.”(6)

It was not until 1886 that Darwin’s prediction of the pollinator was put to the test by Alfred Russel Wallace, the father of biogeography (7). It was from his personal journals that the following account is taken:

“That evening, I stationed myself behind a rosewood tree, gaining a good vantage on the orchid but exposing little of myself to the pollinator regardless of the direction from which it might approach. The flower was swollen within its bud but, although I waited hour after hour through the long night, it was not until the stars disappeared from the sky in the gray light of dawn, that the flower finally opened. In truth, I had fallen asleep and was awakened by a musky smell that reminded me of youthful indiscretions that I need not dwell on here [see journals 8, 11, and 12]. The mimicry exhibited by the opened blossom was greater than I would have believed possible. The two petals curved downward to hide all but the pseudolegs of the labellum, but these crossed and uncrossed in the slightest breeze such that it seemed a real woman waited impatiently for her lover. Indeed, hardly had this thought entered my mind, but I detected a disturbance in the underbrush and beheld the approach of a wild hairy creature, which flung itself upon the flower with great ardor. Not fifteen minutes had passed, however, but the creature withdrew from its amorous embrace and proceeded on to another bloom, and from there on to yet another, flitting from blossom to blossom like a large disheveled moth, and moving all the time further away from my observation post. Leaving my station, I slipped from tree to tree so as to gain a closer look at the pollinator, whose identity was obscured in the dim light. Imagine my surprise then, following its withdrawal from a flower not fifteen feet from me, when I beheld that it was my old mentor Charles Darwin. Truly my surprise cannot be accurately measured for the good man I now saw had been buried four years previous at Westminster Abbey. But the truth of his identity was proved when he with equal incredulity cried, “Alfred,” then hastily pulled up his trousers. He subsequently revealed that his coffin had contained a straw dummy with a melon for its head, and that this had served as a distraction so that he might embark on a new set of travels. Neither of us, however, desired to linger in conversation because of the discomfort attendant upon the circumstances, and Charles soon bid me good-bye. ‘Please don’t tell Emma,’ he said, from which I understood that he had not taken his wife into confidence (8). As he turned to leave, I noticed a dusting of golden pollen now decorated the shoulders of his jacket, and I could not help but think that although his solution to the riddle of the pollinator had been a near miss, he had probably known the correct answer all along.”

Notes:

Those in the field of paleobotany are all too familiar with how any learned discussion at scientific meetings on the evolutionary history of C. homocopulus invariably results in a shouting match (9). On the one side are the neo-Darwinists with their insistent chants of “Darwin was right.” They claim that even if lemurs no longer pollinate the orchid, that the pseudomimicry originally arose to take advantage of the indigenous population of giant lemurs, and only upon their extinction did the orchid morphology adapt to the increasing human population. On the other side are the Wallaconians with their cries of “Darwin sucks sap.” They insist that hominids have always been the pollinators and that C. homocopulus represents a remarkable case of co-evolution between flower and pollinator that extends back to prehistoric man.

What is clear is just how rapidly the C. homocopulus flower has changed in the last few hundred years, resulting in a plethora of subspecies that mimic women of every form and nationality. It has been suggested that this is due to selective breeding initiated in the 1700’s by local entrepreneurs catering to the pirate colonies that sprang up at Fort Dauphin and St. Mary’s Island (10). Indeed, modern-day visitors to Madagascar interested in viewing a living example of C. homocopulus need not bushwack through the jungles but can instead visit any one of a dozen “hot houses” still in existence. Upon payment of a modest fee, the visitor will be escorted to a private room wherein he or she may view the specimen for up to 30 minutes. Unfortunately, neither photography or videotaping is allowed, but good reproductions in a variety of formats may be purchased at the front desk.

FOOTNOTES

(1) I couldn’t resist the pun on ‘bloom’.

(2) There are a number of humorous genus and species names in the real world. These include Agra vation and Agra phobia (both beetles), Ba humbugi (a snail), Pieza deresistans (a fly), Oedipus complex (a salamander), and Carmenelectra shechisme (a fossil moth, the name of which is pronounced “Carmen Electra, she kiss me”).

(3) On the Origin of the Species was published in 1859, but it was in On the Various Contrivances by which British and Foreign Orchids are Fertilized by Insects published three years later, that Darwin provided a detailed examination of how natural selection could operate. This book is notable for developing the idea of co-evolution, exploring how flowers and insects had co-evolved for pollination.

(4) In some orchids, the labellum of the flower mimics the color, shape, and even smell of a female insect. This serves to attract a male insect, which in attempting to mate with the flower pollinates the orchid, a biological tidbit that was one of the key inspirations for C. homocopulus. Before writing this particular section, I read some of Darwin’s writings so that I could mimic his style (‘I do not hesitate’; the use of exclamation marks in a scientific work!). The description of the folios in the herbarium owes a little to my postdoctoral years in the Botany Department at the University of Wisconsin, which had a wonderful herbarium.

(5) Darwin’s most famous orchid example was from Madagascar and so I set this piece there, searching on-line to gain information on ecological and geographical matters.

(6) Darwin, upon discovering that the orchid Angraecum sesquipedale of Madagascar had a nectar well that was almost a foot long, predicted that a moth must exist with a proboscis of similar length, so that it could reach the nectar at the bottom of the well. This is one of the most famous examples of zoological detection and the other key inspiration for C. homocopulus. This hawk moth, when eventually discovered in 1903, was named the Predicta moth (Xanthopan morganii praedicta) in Darwin’s honor. But the actual quote I used comes from Alfred Wallace who, like Darwin, took an interest in pollination of the orchids and wrote in 1867: “That such a moth exists in Madagascar may be safely predicted; and naturalists who visit that island should search for it with as much confidence as astronomers searched for the planet Neptune—they will be equally successful !”

(7) Alfred Wallace independently arrived at the concept of evolution by natural selection and it was his correspondence with Darwin that spurred Darwin to finally publish his own ideas on the subject, ideas he had been wrestling with for the two decades since his world-wide voyage on the HMS Beagle. Wallace was a traveling naturalist and one of the foremost authorities on the geographical distribution of animal species around the world. It was a happy coincidence when I found out that he had followed up on Darwin’s interest in orchid pollination and had actually visited Madagascar.

(8) At the age of 29, Darwin married his cousin Emma Wedgewood. She accepted his marriage proposal even though she did not agree with his religious viewpoints, and worried that these might separate them in the afterlife. There has been some conjecture that Darwin held off on publishing his thoughts on the transmutation of species by natural selection so as not to offend her beliefs.

(9) The theory of evolution by natural selection was controversial in its day, but thankfully that controversy is well behind us (Oh sorry, my mistake, for a moment I thought I lived on a rational planet).

(10) I had recently read a book on the history of pirates and—all praise to serendipity!—Madagascar was part of that history.

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5 Comments leave one →
  1. February 3, 2011 6:31 am

    Wonderful! Exceptionally enjoyable, and who doesn’t need a laugh in today’s world. Thank you.

    • Eric Schaller permalink
      February 3, 2011 7:02 am

      My wife suggested this as the topic for my post, so I’ll share the thanks with her. Glad you liked it.

  2. Michelle Wauchope permalink
    March 9, 2011 8:22 am

    I’ve been one of those lurkers who have enjoyed all of your posts here on the website – but I was keen on pointing a friend to your one on homeotic genes… and it seems to have disappeared.

    Will it be returning?

    • Eric Schaller permalink
      March 9, 2011 8:54 am

      Sorry for the ghost-like appearance and disappearance of that column earlier this week–it will be up tomorrow in more corporeal form! Glad you’re enjoying these (and referring friends to them).

      • vayshti permalink
        March 9, 2011 9:03 am

        Thanks for letting me know. I could have just forwarded her the email version, but I’d rather point others to the website version via my blog at the same time. So I’ll be patient!

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