Ants are friendly to some trees, but not others

The research, published in the November issue of the American Naturalist, is the first to document that ants bore into live trees, and it reopens a centuries-old debate on the relationship between ants and plants.

Ants and certain species of plants and trees have cozy relationships. Myrmecophytes, also knows as ant-plants, have hollow stems or roots that occur as a normal part of their development. Ant colonies often take residence in these hollows. To protect their homes, the ants patrol the area around the tree, killing insects that want to eat the plant's leaves and sometimes destroying vegetation of other plants that might compete for precious soil nutrients and sunlight. The relationship is a classic biological mutualism. The ants get a nice place to live; the trees get protection. Everybody wins.

But while researching ant-plants in the Amazonian rainforests of Peru, Douglas Yu of the University of East Anglia and Glenn Shepard of Sao Paulo University were tipped off by the local people about a strange phenomenon. The natives showed the researchers several non-myrmecophyte trees with swollen scars called galls on their trunks and branches. When the researchers cut into the galls, they found that ants had excavated tunnels into the live wood.

“Ants are superb ecosystem engineers,” David Edwards the lead author of the study said, “but this is the first example of ants galling trees to make housing.”

Megan Frederickson, a Harvard biologist and member of the research team, searched 1,000 square kilometers of forest and found numerous galled trees inhabited by ants, suggesting the behavior is not uncommon. The galled trees were only found on the edges of “Devil's gardens”—ant-made forest clearings that surround stands of ant-plants. It appears, the researchers say, that when the colonies fill the available space in the ant-plants, they branch out and carve new nests into neighboring trees.

The discovery reopens a debate that raged among Charles Darwin and his contemporaries about the relationship between ants and plants. Darwin believed—rightly as it turned out—the hollow spaces in ant-plants occurred as part of the plant's normal development. Since the ants did no damage to the plant, the relationship could be considered a mutualism. Botanist Richard Spruce disagreed. He believed the ants bored the hollows themselves and that the trees needed ants “like a dog needs fleas.” In Spruce's view, ants are parasites.

Studies in the 1960s showed definitively that ant-plant hollows occur normally, vindicating Darwin. But this latest finding that ants do gall non-myrmecophytic trees shows that Spruce wasn't so wrong after all.

David P. Edwards, Megan E. Frederickson, Glenn H. Shepard and Douglas W. Yu, “A Plant Needs Ants like a Dog Needs Fleas: Myrmelachista schumanni Ants Gall Many Tree Species to Create Housing.” The American Naturalist 174:5 (Nov. 2009).

Since its inception in 1867, the American Naturalist has maintained its position as one of the world's most renowned, peer-reviewed publications in ecology, evolution, and population and integrative biology research.

Media Contact

Kevin Stacey EurekAlert!

More Information:

http://www.uchicago.edu

All latest news from the category: Life Sciences and Chemistry

Articles and reports from the Life Sciences and chemistry area deal with applied and basic research into modern biology, chemistry and human medicine.

Valuable information can be found on a range of life sciences fields including bacteriology, biochemistry, bionics, bioinformatics, biophysics, biotechnology, genetics, geobotany, human biology, marine biology, microbiology, molecular biology, cellular biology, zoology, bioinorganic chemistry, microchemistry and environmental chemistry.

Back to home

Comments (0)

Write a comment

Newest articles

Lighting up the future

New multidisciplinary research from the University of St Andrews could lead to more efficient televisions, computer screens and lighting. Researchers at the Organic Semiconductor Centre in the School of Physics and…

Researchers crack sugarcane’s complex genetic code

Sweet success: Scientists created a highly accurate reference genome for one of the most important modern crops and found a rare example of how genes confer disease resistance in plants….

Evolution of the most powerful ocean current on Earth

The Antarctic Circumpolar Current plays an important part in global overturning circulation, the exchange of heat and CO2 between the ocean and atmosphere, and the stability of Antarctica’s ice sheets….

Partners & Sponsors