In a remarkable example of David and Goliath proportions, a recent study found that certain ants in Africa can keep any animal, including elephants, away from Acacia trees of their choosing.  For all their size, elephants walk a wide circle around trees where ants have staked their claim. And for all their size, ants seem to command some serious bragging rights. – Global Animal

The New York Times, Sindya N. Bhanoo

Campers know the pesky feeling of ants crawling up and down their arms and legs.

For elephants in Kenya’s central highlands, the sensation is disturbing enough to keep them far away from a variety of tree they would otherwise enjoy eating, according to a study in Current Biology.

The tree, known as the Acacia drepanolobium, is a generous home to ants that live in its bulbous swellings and feed on a sugary solution it produces. In return, the ants serve as guardians, instantly attacking any creature that approaches the tree. In the case of elephants, ants crawl up the inside of their trunks and agitate sensitive nerve endings.

“An elephant’s trunk is a truly remarkable organ, but also appears to be their Achilles’ heel when it comes to squaring off with an angry ant colony,” said Todd M. Palmer, a biologist at the University of Florida and the paper’s co-author.

In conducting their study, the researchers presented elephants with tree branches from the ant tree but without ants. The elephants hungrily ate them.

Conversely, when presented with branches from one of their favorite trees that the researchers populated with ants, the elephants detected the ant odor and stayed away.

“What we found is that they like to eat the ant plant as much as their favorite plants, when there are no ants on them,” Dr. Palmer said.

The little ants end up playing a critical regulatory role in the savanna’s ecosystem, he said, ensuring the presence of tree cover and helping control wildfires, since fire spreads faster across grass than through trees.