The following has been modified from my field notes from when I took tropical ecology and did a field session in Belize.
In the rainforest ecosystem, the number of symbiotic relationships between organisms is astounding. For example, the relationship between leafcutter ants and the fungus is highly observable in Belize. There is such a great number of these ants that paths are created by them. Leafcutter ant is a generic term for one of 47 species, in the orders Atta and Acromyrmex. They take leafs from plants and chew them up, this plant material is then fed to a fungus, which they eat. In a sense they are farmers. Since the fungus receives a habitat and the ant receive food, this symbiotic relationship is mutualism. There is a dark side to this relationship though. If a plant is highly desirable by ants they will highly predate on said plant. Because of this, they are seen as pests by farmers, whose crops they can destroy.
We saw a wide variety of epiphytes growing on a wide range of trees. Epiphytes are plants that live on the bark and the branches of other trees. This feature allows the plant to gain access to light with a limited energy investment. Most plant growth is limited by sunlight, water availability, and temperature. They are not parasitic but their weight can damage trees. This is an example of commensal as the trees are not harmed but the epiphyte benefits from the relationship. At the Mayan ruins, we saw one plant that has adapted to solve this issue by shedding its bark, so the epiphytes fall off with the bark. This worked fairly well for the tree but in one area a plant had managed to survive on the tree. The most commonly recognized epiphytes are pitcher plants, “air plants”, and mistletoe (Santalales).