In tropical forests, there are plants known as ant-plants. These plants host ant colonies. When the ant colony is the species Petalomyrmex phylax, the presence of the ants protects the ant-plants from predation by herbivores. However, the ant species Cataulacus mckeyi takes advantage of the nesting place and nectar the plants provide without affording any protection to the plant. The interspecies interaction between the ant-plants and P. phylax is an example of , whereas the interaction between the ant-plants and C. mckeyi is an example of .

Mutualism is an biological interaction between species, where each species benefits. In the first case, the ant-plants and the P. phylax benefits from each other.

Commensalism in a biological interaction where one species receive benefits from other species, but the other specie do not get any benefits or get harmed. In the second case only one species receive benefits, C. mckeyi, the ants, while the ant-plants does not receive benefits nor get harmed