Ecological Principles

Epiphytes are plants that grow on other plants, often on trees, and do not harm them. They derive nutrients and water from the air and rain, not from the host plant. The relationship between epiphytes and the mango tree is an example of commensalism, where the epiphytes benefit from the host plant without harming it. The mango tree does not gain any benefit, nor does it suffer harm from the epiphytes. Thus, the correct answer is Commensalism.