Ecologists have discovered the secret weapon used by certain acacia trees to defend themselves against ravenous elephants: ants.
The finding could one day help conservationists protect vulnerable plants from elephants and other large herbivores, said University of Florida biologist Todd Palmer, who reported the discovery online Thursday in the journal Current Biology.
Elephants can have a devastating impact on the trees of the African savannas, Palmer said. A hungry pachyderm can easily demolish a tree, wrapping its prehensile trunk around thick branches and ripping them off. A herd of them can lay waste to an area -- a problem for people trying to protect wild lands or cropland.
Yet elephants always seem to avoid one particular type of acacia tree called Acacia drepanolobium, also known as the whistling-thorn tree.
What sets these acacias apart is the ants that inhabit them. The insects live in the trees' golf-ball-sized "swelling thorns" and feed on the nectar that oozes from the base of each leaf, Palmer said. In return, they provide the tree with bodyguard service, swarming out of the tree to face any attack.