Sex in the Garden: Tongue Orchids and their Dupes

In Science on 15 August 2011 tagged Insects, Orchids, Pollination, Sex, Wasps

You already know that orchids have pretty freaky sex lives. They depend on insects to carry their pollen from one flower to another, and employ a number of techniques to entice the bugs to visit. It turns out, some of those techniques are more successful than they need to be.

Take the Australian tongue orchid (Cryptostylis). The color, shape, and smell of its flower mimics a female wasp, so the male is attracted to it. Its pollinator is the Lissopimpla excelsa, or “Orchid Dupe Wasp.” (Imagine being named after your least complementary trait! Poor dupe.)

But here’s where things get interesting. In a study published in The American Naturalist in 2008, researchers found that most of these orchid-wasp pairings resulted in a “happy ending” for the pollinator. Yes, they found ejaculate in most of the flowers.

(Let’s just pause here for a moment to think about people collecting wasp spooge from orchids for science. Great job.)

The study claims to be “the first conclusive evidence of insect ejaculation in response to floral stimuli.” And they proved that these orchids have a far higher pollination rate than other orchids because of it.

This revelation led to some fascinating questions. If Dupe wasps are wasting all their valuable sperm in flowers, doesn’t that mean the female Dupes are left wanting? And wouldn’t that lead to an inevitable decline in the wasp population? And if these wasps are the only pollinators for the Cryptostylis orchids, how can they survive? Thankfully, nature always finds a way.

It turns out the Dupe wasps are haplodiploids. That means that, in addition to mating the old fashioned way, the females can also produce offspring all by themselves. When they do, those offspring are always male. So the orchids lure the male Dupes away, and the female Dupes just make more. Nature is clever, if not always kind.

Want more Sex in the Garden? Check out these fine posts from my fellow Bay Area Plant Bloggers, who all have sex on the brain today.

• Insects, Nature’s Pimps in Dirty Girl Gardening.
• Botanical Tramp Stamps in Phyteclub.
• Fatal Seduction in The Pitcher Plant Project.

Photo from the study, copyright Esther Beaton.

See Also

• Pollination By Post
  Back in May, my friend Zach sent me some pollen from one of his Phalaenopsis orchids in the mail.
• A Dendrobium Seed Pod and the Long Chain of Ifs
  That tiny fluff is just the packaging - the seeds are too tiny to be visible to the naked eye.
• I Think I Impregnated My Dendrobium
  Try, try again.