An Azteca ant approaches a caterpillar on a laurel leaf in Jalisco, Mexico. After making such a find, it will recruit nestmates to the leaf to bite the caterpillar's underside until it drops off the leaf. Credit: Elizabeth G. Pringle. Partnerships between ants and trees are classic examples of mutualism in nature---the trees provide room and board for the ant colonies who protect the trees from pests. This seems like a pretty good deal, and two studies published this week show that some of these partnerships can vary with environmental conditions and others may even be irresistible---literally.
The first symbiosis takes place in Mexico and Central America, where Azteca ants nest in the stem cavities of laurel trees. Laurel trees are especially vulnerable to leaf-eating pests during dry spells, so the tree has evolved a cooperative solution: bodyguard ants. Comparing ant colonies across 26 sites with varying amounts of rain, ...
