A Pseudomyrmex peperi acacia ant attacks a photographer who has brushed up against her tree. Note the standard ant stinging technique of anchoring with the mandibles for leverage to plant the stinger. Cayó District, Belize.
Portrait of a mutualism: a swollen-thorn Acacia with the ants that protect it. The hundreds of thorns on a mature tree can house colonies of up to 20,000 ants. Chiriqui, Panama
Not all of the thorns on a swollen-thorn Acacia house the ants' larvae, but those that do are heavily guarded. Here, Pseudomyrmex spinicola patrol a nest entrance, ready to use their stings if the photographer approaches too close. Chiriqui, Panama.