Pseudomyrmex ferrugineus
Cuilapa, Santa Rosa, Guatemala

photograph © Alex Wild 2003

Swollen-thorn Acacia plants live in a mutualistic symbiosis with Pseudomyrmex ants in Central America.  The aggressive, stinging ants protect the plant from herbivory.  In return, the plant feeds the ants with nectar and protein-rich Beltian bodies while providing living space for the ants in hollow thorns.  Here is a cross-section of a swollen thorn, revealing ant brood.  Living up to their reputation, the ants didn't let the intrepid photographer make this incision on the Acacia without suffering numerous stings.

This image is copyrighted by the photographer and cannot be used without permission. To obtain permission to use this image, please email Alex Wild. (alwild (at)  Most of the photographs on are reduced from their original size and compressed for more efficient web transmission.  In some cases, higher quality versions are available.

This image was captured with a Nikon Coolpix 995.