Devil’s Garden: Ecology

Music
Ambience Peruvian rainforest

Deep in the Peruvian rainforest, a “devil’s garden” is a place where only one kind of tree grows, in an area cleared of the forests’ usually diverse vegetation. Local myths blame this phenomenon on an evil spirit. But, according to Stanford doctoral student Megan Frederickson, it’s an ant that’s responsible for creating the devil’s gardens. I’m Jim Metzner and this is the Pulse of the Planet.

“The tree species that lives in devil’s gardens is an ant plant, and by that I mean that it has swollen, hollow stems in which ants nest.”

Frederickson and her colleagues found that the ants wiped out plants other than their hosts by giving them an injection of their own special brand of herbicide — formic acid, which they store in their abdomens.

“The reason that the ants weed out all plants but their host plants from the devil’s gardens is to create more space for their host plant to grow, and, as a result, it’s sort of a service that’s one step removed. They eliminate the competition for the tree that they live in so that there can be more trees for them to expand their colony into.”

The relationship between the ant and its tree-home is evidence of the subtle ecological balance that exists in rainforests.

“The remarkable thing about the devil’s gardens and the ant colonies that make them is the extent to which the ants are able to modify their environment. These tiny, tiny ants control an area that’s very large and produce a garden of the tree that they live in in order to provide abundant nest sites for their own colony. Tropical rainforests are really hotbeds of beneficial relationships between different species.”

So the ants that live in devil’s gardens are sort of angels, in a way, in keeping the rainforest ecosystem in balance. Pulse of the Planet is made possible by the National Science Foundation. I’m Jim Metzner.

Devil's Garden: Ecology

Are the ants in Devil's Gardens actually angels?
Air Date:03/22/2006
Scientist:
Transcript:

Music
Ambience Peruvian rainforest

Deep in the Peruvian rainforest, a “devil’s garden” is a place where only one kind of tree grows, in an area cleared of the forests’ usually diverse vegetation. Local myths blame this phenomenon on an evil spirit. But, according to Stanford doctoral student Megan Frederickson, it’s an ant that’s responsible for creating the devil’s gardens. I’m Jim Metzner and this is the Pulse of the Planet.

“The tree species that lives in devil’s gardens is an ant plant, and by that I mean that it has swollen, hollow stems in which ants nest.”

Frederickson and her colleagues found that the ants wiped out plants other than their hosts by giving them an injection of their own special brand of herbicide -- formic acid, which they store in their abdomens.

“The reason that the ants weed out all plants but their host plants from the devil’s gardens is to create more space for their host plant to grow, and, as a result, it’s sort of a service that’s one step removed. They eliminate the competition for the tree that they live in so that there can be more trees for them to expand their colony into.”

The relationship between the ant and its tree-home is evidence of the subtle ecological balance that exists in rainforests.

“The remarkable thing about the devil’s gardens and the ant colonies that make them is the extent to which the ants are able to modify their environment. These tiny, tiny ants control an area that’s very large and produce a garden of the tree that they live in in order to provide abundant nest sites for their own colony. Tropical rainforests are really hotbeds of beneficial relationships between different species.”

So the ants that live in devil’s gardens are sort of angels, in a way, in keeping the rainforest ecosystem in balance. Pulse of the Planet is made possible by the National Science Foundation. I’m Jim Metzner.