These acacias have swollen thorns , which provide an environment which the ants can carve out into a nest. The leaf petioles have nectaries which secrete carbohydrate-rich nectar which is consumed by the ants. Finally, the tips of the leaflets produce protein-rich Beltian bodies which the ants gather. This includes not only insects but also grazing animals and even people. And, they chew other plants which grow around the acacias, thus preventing those plants from shading the acacias and supressing growth.
Figs have a very unusual flowering system.
The flowers are on the inside of a structure called a syconium , which will develop into the ripe fruit we know as a fig. The female fig wasp enters the syconium through an opening called the ostiole . It carries pollen and pollinates the flowers on the inside of the hollow syconium. At the same time, it lays eggs into flowers with short styles. The eggs hatch in the ovaries of the short-styled flowers and the larvae consume the ovary tissue as they grow.