EXOPULMONARY ORGAN. “The structure of the Macrotermes mound is strongly differentiated from that of the nest, which is the genus’ fourth distinctive feature: the mound is an organ of “extended physiology” that serves a physiological function, capturing energy in turbulent wind to power respiratory gas exchange for the colony. The need for such an organ is considerable: the collective metabolism of the termites and fungi is equivalent to that of medium-size to large domestic livestock.”
https://link.springer.com/article/10.1007/s12304-016-9256-5