Plants can grow quickly or ward off hungry insects, but not both: research

Mar 25, 2010
Plant-eating insects such as this silhouetted caterpillar have played a pivotal role in the evolution of plants. Photo by Ellen Woods, Cornell University

There's a war occurring each day in our backyards - plant versus plant-eating insect versus insect-eating insect. Research by UC Irvine's Kailen Mooney suggests the outcome - of interest to farmers - is a stalemate.

For a study published online Friday, March 26, in the journal Science, Mooney and colleagues studied 16 species of milkweed, a group of found throughout the Western hemisphere.

The scientists sought to determine the relationship among , how plants defend themselves against plant-eaters (with thorns and toxins, for example), and the protection plants receive from such as ladybugs that eat plant-hungry insects. The herbivores - in this case bright yellow aphids - damage plants; ladybugs can act as bodyguards, helping plants by eating aphids.

The researchers asked: Can plants have it all? Can they grow quickly and defend themselves against herbivores while at the same time solicit protection from ladybugs and other bodyguards?

The answer: No.

Milkweed species that grow quickly (a desirable trait) are more vulnerable to insects that feed on them (an undesirable trait), making those plants more dependent upon predators for their survival. In other words, you can be either a hard-to-eat, slow growing plant that doesn't need bodyguards, or a tasty, fast-growing plant that relies on outside protection.

The finding could be important to farmers trying to develop herbivore-proof, fast-growing crops, and it betters our understanding of how the natural world works.

"We can breed plants to for fast growth, but if we do that, it appears we're weakening the plants' immunity against , making them more dependent upon protection from potentially unreliable predators," says Mooney, assistant professor of ecology & evolutionary biology.

And there may not be much that farmers can do.

"Milkweed has been evolving for as many as 20 million years. Natural selection favors faster-growing plants and those that easily fight off insects," Mooney says. "If nature hasn't found a way to combine both, perhaps it's something that cannot be done."

Cornell University scientists Rayko Halitschke, Andre Kessler and Anurag Agrawal also worked on this study, funded in part by the National Science Foundation.

Explore further: Research shows impact of BMR on brain size in fish

Related Stories

Sex involved in plant defense

Jul 13, 2009

Why do some plants defend themselves from insect attacks better than others? New evidence shows that the difference might be due to whether they're getting any plant love.

Insects use plant like a telephone

Apr 23, 2008

Dutch ecologist Roxina Soler and her colleagues have discovered that subterranean and aboveground herbivorous insects can communicate with each other by using plants as telephones. Subterranean insects issue chemical warning ...

Whiteflies sabotage alarm system of plant in distress

Nov 26, 2009

(PhysOrg.com) -- When spider mites attack a bean plant, the plant responds by producing odours which attract predatory mites. These predatory mites then exterminate the spider mite population, thus acting ...

Virus pulls bait and switch on insect vectors

Feb 01, 2010

A common plant virus lures aphids to infected plants by making the plants more attractive, but when the insects taste the plant, they quickly leave for tastier, healthier ones. In the process, the insects ...

Recommended for you

Research shows impact of BMR on brain size in fish

Apr 24, 2015

A commonly used term to describe nutritional needs and energy expenditure in humans – basal metabolic rate – could also be used to give insight into brain size of ocean fish, according to new research by Dr Teresa Iglesias ...

Why do animals fight members of other species?

Apr 23, 2015

Why do animals fight with members of other species? A nine-year study by UCLA biologists says the reason often has to do with "obtaining priority access to females" in the area.

Dolphins use extra energy to communicate in noisy waters

Apr 23, 2015

Dolphins that raise their voices to be heard in noisy environments expend extra energy in doing so, according to new research that for the first time measures the biological costs to marine mammals of trying ...

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.