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SEXY SUNDAYS: Deceptive Liaisons

Posted by Richard Conniff on December 21, 2008

orchid-that-lures-insects-with-sex1Pseudocopulation.  Does that sound like your sex life lately?  Or maybe you feel now and then as if you’ve been led on with false hopes–teased even–by a member of the opposite sex?

Well, stop feeling sorry for yourself.  Here’s a story about creatures that gets duped by, of all things, a flower.

First a little background:

Plants attempting to swap genetic material usually employ two basic pollination strategies. They broadcast copious amounts of tiny pollen grains into the air, making life miserable for people with allergies.  Or they lure insects with pretty flowers full of nutritious nectar and the insects inadvertently carry away pollen for delivery to the next plant.

But certain species employ–or maybe “turn” is the right word– some surprising tricks.  For instance, some orchids attract the services of insect pollinators by providing sexual favors.

These orchids, like the Sicilian specimen of Ophrys ciliata in the photo, mimic the shape and coloration of female bees, wasps, flies, and winged ants.  They also release osmophores—chemicals that duplicate the sexual perfume, or pheromones, of these insects.

It drives males wild.  In Australia’s aptly named orchid dupe wasps,males may prefer the make-believe females  to real ones.  (Does this sound depressingly familiar?)  They’ll actually break away from having sex with a real female to pseudocopulate with a flower.

Is it good for the flower?  Yes, because, as a result of these intimate attentions, the wasp goes away carrying a pollen sac, or pollinia. And for the wasp? The experience must also be good, at least in theory, because the pollination only works if the wasp decides to have another go next time he sees a flower of the same type.

And now it’s not just theory:  A recent study of Australian tongue orchids of the genus Cryptostylis  found that flowers with the most extreme sexual behavior have the highest rates of pollination.  And long, vigorous bouts of pseudocopulation with a flower actually cause male wasps to ejaculate.  Since male insects often invest large amounts of costly nutrients and other materials in their sperm packets, this can be a big stupid mistake, reproductively speaking.  But orchids and wasps both manage to survive in what may be a sexual arms race.  

No word from the study on just how hurt and angry the female wasps are feeling.   But don’t send flowers.

##

Further reading:

A. C. Gaskett, C. G. Winnick, and M. E. Herberstein1, “Orchid Sexual Deceit Provokes Ejaculation” Am Nat 2008. Vol. 171, pp. E206–E212

One Response to “SEXY SUNDAYS: Deceptive Liaisons”

  1. Jim Conniff said

    My experience with nature in all its endlessly weird manifestations, albeit a trifle longer than that of your on-site expert Richard Conniff, bends to bear him out. I used to think the tales of Bavarian bumble bees Uncle Fritz regaled me with in my impressionable early childhood were made of whole cloth, as the saying used to go. That is, until I got crocked on the dish of mashed chokecherries your writer reports Fritz mixed his illegal gin with to make Pink Ladies, reputedly the best in Westchester County. I can attest to the residual effect thereof, as my brief whirl in the “front room” bore witness. All this makes me wonder if genetic alcoholism may have led to Fritz’s calling his Black Forest creatures “bumble” bees.

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