Tropical rain forests have been called the "jewels of the earth" due to the rich diversity found in their flora and fauna. La Selva Biological Station in Costa Rica is a preserve where scientists conduct research on the rain forest's role in world ecology. Ants of many species enjoy nectar produced by Inga thibaudiana, a relatively small tree found in the La Selva area. This nectar does not come from flowers, but from nectaries, little bowl-shaped structures growing between leaflets (or little leaves). In this photograph, you see two ants drinking from the nectaries. The ant-tree relationship is mutually beneficial. In return for the food, the ants protect young leaves from leaf-eating insects, fungi, and encroaching vines.