Azteca ants Azteca sp. patrolling leaf of Cecropia tree Cecropia sp. in French Guiana rainforest. These two species form a symbiotic relationship whereby the Cecropia provides a nesting area filled with a sugary food within its hollow trunk and the Azteca, in turn, cut away encroaching plants and defend the tree against herbivore invaders. These fierce ants, less than 2 millimeters in length, are extremely defensive and deliver painful bites to people and animals even brushing up against the tree.