In fact, every time a termite larva molts, it sheds the lining of its gut as well, and needs to get re-supplied with protozoans. Adults excrete a special substance that contains the symbionts and feed it to the larvae. The bacteria live in nodules in the plant roots. They fix the nitrogen, and release excess ammonia and nitrates into the nodule, where they are taken up by the legumes. In return the bacteria obtain nutrients from the plants.
Brazil nuts grow in a capsule in the tops of the Brazil-nut tree.
These trees are often 120 feet tall. The fruit capsules are large and heavy, containing somewhere around 15 brazil nuts. Since the capsule is very thick it does not break open when it falls to the ground unlike some fruits. An agouti gnaw open the capsule and eat a number of the seeds, but usually not all. Both the tree and the agouti benefit from this relationship.