Self-pollinating plants more likely to become extinct

Scientists have shown in a recent study that plants that pollinate themselves are more likely to become extinct.
Working with the nightshade plant family, which includes potatoes, peppers, tomatoes and tobacco, the researchers compared speciation and extinction rates for nightshade species that mate exclusively with other plants, versus species that can pollinate themselves.

As Boris Igic, a biologist at the University of Illinois explains: "Plants just can't walk over to potential mates like we do. Many species rely on wind or pollinators coming to them." About half of all flowering plants have another option, said Igic - they can fertilise themselves.

The results collected showed that despite short-term benefits of solitary sex (including not having to rely on wind currents and insects to the job), the plants which exclusively self-pollinated suffered over time.

"Species that can pollinate themselves have much higher extinction rates," says Igic.

The researchers say that a lack of genetic diversity may be the cause of the increased extinction rates the self-pollinated plants. Plants that can pollinate themselves are simply less likely to inherit the genetic variants that enable them to adapt to changing environments.

"It's like playing the stock market," says Stephen Smith, a co-author on the study. "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."