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: Science casts light on sex in the orchard

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

Science casts light on sex in the orchard

13 hours ago

Persimmons are among the small club of plants with separate sexes—individual trees are either male or female. Now scientists at the University of California, Davis, and Kyoto University in Japan have discovered ...

Four new dragon millipedes found in China

15 hours ago

A team of speleobiologists from the South China Agriculture University and the Russian Academy of Sciences have described four new species of the dragon millipedes from southern China, two of which seem to ...

Scientist creates automatic birdsong recognition app

18 hours ago

Dr Dan Stowell, an EPSRC Research Fellow in QMUL's School of Electrical Engineering and Computer Science, has used a grant from Queen Mary Innovation to develop a prototype for an app that turns his research ...

New research reveals fish are smarter than we thought

19 hours ago

(Phys.org) —A new study from researchers in our Department of Psychology with colleagues at Queen Mary University of London has reported the first evidence that fish are able to process multiple objects ...

User comments : 0

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.