New research explains orchids' sexual trickery

Dec 17, 2009

A new study reveals the reason why orchids use sexual trickery to lure insect pollinators. The study, published in the January issue of The American Naturalist, finds that sexual deception in orchids leads to a more efficient pollinating system.

While most reward pollinators with tasty nectar, many species turn to trickery. Some use what's called food deception. They produce flowers that look or smell like they offer food, but offer no edible reward. Other orchids use sexual deception. They produce flowers that look or smell like female insects, usually bees or wasps. Males are drawn to the sexy flowers and attempt to mate with it. In doing so, they accidentally collect pollen on their bodies, which fertilizes the next orchid they visit.

From an evolutionary perspective, the sexual strategy is a bit puzzling. Orchids that offer or mimic food can attract a wide variety of food-seeking pollinators—bees, wasps, flies, ants and so on. But sexual displays are only attractive to the males of a single species—a flower that looks like a female wasp is only going to attract male , not other . So in appealing to sex, these orchids limit their potential pollinators, which would seem to be a reproductive disadvantage.

Despite the apparent drawback, sexual deception has evolved several times in different types of orchids. So there must be some selective advantage, and researchers Salvatore Cozzolino and Giovanni Scopece of the University of Naples Federico II, Steven Johnson of University of KwaZulu-Natal (South Africa) and Florian Schiestl of the University of Zürich appear to have figured out what it is.

Schiestl and his team observed populations of 31 orchid species with varying pollination strategies in Italy and Western Australia. They measured the amount of pollen that was taken from each orchid, and the amount of pollen that made it to its intended destination—another orchid of the same species.

They found that populations of sexually deceptive orchids had higher "pollen transport efficiency" than the species with multiple pollinators. In other words, a higher percentage of the pollen that was taken from sexually deceptive orchids actually made it to another orchid of the same species. The orchids with multiple pollinators had more pollen taken from their flowers, but more of that pollen was lost—dropped to the ground or deposited in flowers of the wrong species.

So it appears that specializing with one pollinator—and appealing to it with sex—makes for a more direct line from one orchid flower to another, with less precious pollen lost in the transport process.

"These results could provide new insights in the understanding of evolutionary shifts between generalized to specialized pollination strategies in flowering plants," says Scopece, "and that sexy orchids do it better!"

Explore further: Orchid named after UC Riverside researcher

More information: Giovanni Scopece, Salvatore Cozzolino, Steven D. Johnson, and Florian P. Schiestl, "Pollination Efficiency and the Evolution of Specialized Deceptive Pollination Systems." The American Naturalist 175:1 (January 2010).

add to favorites email to friend print save as pdf

Related Stories

Orchid sexual deceit has male wasps in a loved-up frenzy

Apr 29, 2008

Orchids are admired by humans and insects alike, but according to Macquarie University research, one Australian wasp is so enthralled by ‘Orchid Fever' that actually he ejaculates while pollinating orchid ...

Australian orchids' sneaky sex tricks

Aug 20, 2007

Australian orchids are engaged in an arms race, using sensory overload to seduce male insects. Macquarie University PhD student Anne Gaskett has discovered just how they do it. Her work is important to the ...

The evolution of orchids

Nov 19, 2009

(PhysOrg.com) -- Charles Darwin and many other scientists have long been puzzled by the evolution of orchids, the largest and most diverse family of flowering plants on Earth. Now genetic sequencing is giving ...

Saving the wild orchids of Borneo

Jul 17, 2008

Borneo (Kalimantan) is the third largest island in the world. It is rich with a variety of indigenous orchid species that grow in the forests. Borneo's rain forests are also home to some extremely rare species of orchids, ...

Recommended for you

Orchid named after UC Riverside researcher

10 hours ago

One day about eight years ago, Katia Silvera, a postdoctoral scholar at the University of California, Riverside, and her father were on a field trip in a mountainous area in central Panama when they stumbled ...

In sex-reversed cave insects, females have the penises

12 hours ago

Researchers reporting in the Cell Press journal Current Biology on April 17 have discovered little-known cave insects with rather novel sex lives. The Brazilian insects, which represent four distinct but re ...

Fear of the cuckoo mafia

12 hours ago

If a restaurant owner fails to pay the protection money demanded of him, he can expect his premises to be trashed. Warnings like these are seldom required, however, as fear of the consequences is enough to ...

User comments : 0

More news stories

Deadly human pathogen Cryptococcus fully sequenced

Within each strand of DNA lies the blueprint for building an organism, along with the keys to its evolution and survival. These genetic instructions can give valuable insight into why pathogens like Cryptococcus ne ...

Hackathon team's GoogolPlex gives Siri extra powers

(Phys.org) —Four freshmen at the University of Pennsylvania have taken Apple's personal assistant Siri to behave as a graduate-level executive assistant which, when asked, is capable of adjusting the temperature ...

Better thermal-imaging lens from waste sulfur

Sulfur left over from refining fossil fuels can be transformed into cheap, lightweight, plastic lenses for infrared devices, including night-vision goggles, a University of Arizona-led international team ...