WARNING: There’s a high yuck factor to this post, it’s not for the squeamish or easily offended!
One of my Twitter contacts, Traci Birge in Finland, has been reading Pollinators & Pollination: Nature and Society, and making some very nice comments about it. I had to laugh at this one in which she describes some plants as “assholes” because of the way in which they deceive pollinators into visiting their flowers but offer no reward in return:
If you follow that thread you can see that Traci was closer to the truth than perhaps she realised: there are some plants with flowers that appear to mimic the anuses of dead mammals, particularly in the families Apocynaceae and Araceae. By their smell, texture, colour and hairiness they are fooling flies into visiting the flowers, because assholes, like any mammalian orifice, provide an entry point for maggots of carrion-feeding flies. Sometimes the deception is so great that the flies lay their eggs on these blooms, though of course the maggots starve.
A great example of an anus-mimicking bloom is the Dead Horse Arum (Helicodiceros muscivorus). Check out the image above: if that doesn’t look like a horse’s ass, I don’t know what does!
Other examples might be found within the stapeliads, especially the genus Huernia which often have a thickened annulus to the centre of the flower. However that could also be interpreted as mimicking an open, inflamed wound on the side of an animal:
As I point out in the book, you might imagine that there would be strong natural selection against flies visiting these flowers if they lose fitness by laying eggs on such an unsuitable substrate. But the flowers are tapping into really deep-seated behaviours and clearly the flies can’t distinguish the flowers from the real thing.
This is flower pollination that is far removed from the deliciously perfumed, cute-and-cuddly, heart-warming world of bees and flowers. Isn’t nature wonderful?
All photos from Wikipedia, as follows:
Helicodiceros muscivorus: Göteborgs botaniska trädgård (photographer: Ingemar Johansson) – http://www.mynewsdesk.com/se/pressroom/goteborgs_botaniska_tradgard/image/view/dracunculus-muscivorus-128973, CC BY 3.0, https://commons.wikimedia.org/w/index.php?curid=19265330
Huernia zebrina: Enzo^ – Own work, CC BY 3.0, https://commons.wikimedia.org/w/index.php?curid=10963668
Huernia schneideriana: Juan Carlos Fonseca Mata – Own work, CC BY-SA 4.0, https://commons.wikimedia.org/w/index.php?curid=94705877