Single parenthood doesn't pay off for plants

Nov 08, 2010

Many plants can pollinate themselves and reproduce without the aid of a mate, thanks to having both male and female parts. But the short-term perks of being able to go it alone come with long-term costs, says a new study in the journal Science. The reason is because plants that can pollinate themselves are more prone to extinction, scientists say.

Flowering are incredibly creative when it comes to sex, said co-author Boris Igic, a biologist at the University of Illinois at Chicago. "Plants just can't walk over to potential mates like we do. Many species rely on wind or coming to them."

About half of all have another option, said Igic — they can fertilize themselves.

Being able to have sex with yourself has some surprising short-term perks, scientists say. Plants that can pollinate themselves can still produce seeds, even when wind or insects don't deliver.

"You don't need a partner to reproduce," said co-author Emma Goldberg of the University of Illinois at Chicago.

"And because you're both the mother and the father of your own seeds, as well as the father of other plants' seeds, you also pass on more copies of your genes." Goldberg added.

Previous work by Igic and others found that many members of the nightshade family — a group that includes potatoes, peppers, tomatoes, and tobacco — gain the ability to mate with themselves over evolutionary time.

"We see a one-way transition where self-incompatible species turn into self-compatible species, but aren't able to go back," said Goldberg.

But what are the long-term consequences of being able to mate with yourself, rather than relying on a partner?

"We wanted to know what happens when species stop relying on other individuals to reproduce," said co-author Stephen Smith, who conducted the study while at the National Evolutionary Synthesis Center in Durham, NC.

To find out, the researchers compared speciation and extinction rates for nightshade species that mate exclusively with other plants, versus species that can pollinate themselves.

The result? Despite the short-term benefits of solitary sex, the single parent option has serious pitfalls over time. "Species that can pollinate themselves have much higher rates," said Igic.

One reason why self-compatible lineages are more likely to die off, the researchers say, may be a lack of genetic diversity. Plants that can pollinate themselves are less likely to inherit the genetic variants that enable them to adapt to changing environments, Smith explained.

"It's like playing the stock market," he added. "If you put all your eggs in one basket you might win big in the short term. But if you don't maintain a diverse portfolio, in the long run you're less able to endure the market's ups and downs."

Explore further: Rare albino sparrow spotted in Australia

More information: Goldberg, E., J. Kohn, et al. (2010). "Species selection maintains self-incompatibility." Science 330(6003): 493 - 495. http://dx.doi.org/DOI:10.1126/science.1194513

Study data are available in the Dryad Digital Repository at www.datadryad.org/handle/10255/dryad.1888

Related Stories

Nightshades' mating habits strike uneasy evolutionary balance

Oct 21, 2010

Most flowering plants, equipped with both male and female sex organs, can fertilize themselves and procreate without the aid of a mate. But this may only present a short-term adaptive benefit, according to a team of researchers ...

Third gender identified in a close relative of the olive tree

Mar 30, 2010

A hitherto unknown reproductive system in a species closely related to the olive tree, Phillyrea angustifolia L., has been discovered by French researchers. This system explains the high concentration of male individuals co-occ ...

Tracking Genes for Self-pollination in Arabidopsis

Apr 27, 2007

Some plants need a partner to reproduce. Pollen from one plant pollinates the stigma of another, and a seed is formed. But other plants can self-pollinate, a handy survival mechanism for a lonely plant.

UCSD Biologists Find New Evidence for One-Way Evolution

Jan 18, 2006

By tracing the 30-million year history of variation in a gene found in plants such as tomatoes and tobacco, biologists at the University of California, San Diego have found new evidence to support an old idea ...

Recommended for you

Birds time breeding to hit 'peak caterpillar'

1 hour ago

When oaks burst into life in spring populations of oak-leaf-eating caterpillars boom: this offers a food bonanza for caterpillar-munching birds looking to raise a family.

11 new species come to light in Madagascar

7 hours ago

Madagascar is home to extraordinary biodiversity, but in the past few decades, the island's forests and associated biodiversity have been under greater attack than ever. Rapid deforestation is affecting the ...

Birds 'weigh' peanuts and choose heavier ones

May 23, 2015

Many animals feed on seeds, acorns or nuts. The common feature of these are that they have shells and there is no direct way to know what's inside. How do the animals know how much and what quality of food ...

Estuaries protect Dungeness crabs from deadly parasites

May 22, 2015

Parasitic worms can pose a serious threat to the Dungeness crab, a commercially important fishery species found along the west coast of North America. The worms are thought to have caused or contributed to ...

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.