A Beltian body is a detachable tip found on the pinnules of some species of Acacia and closely related genera. Beltian bodies, named after Thomas Belt, are rich in lipids, sugars and proteins and often red in colour. They are believed to have evolved in a symbiotic relationship with ants. The ants live inside special plant structures (domatia) or near the plant and keep away herbivores.[citation needed]