The pupal molting fluid has evolved social functions in ants

Insect societies are tightly integrated, complex biological systems in which group-level properties arise from the interactions between individuals. However, these interactions have not been studied systematically and therefore remain incompletely known. Using a social isolation approach, we discovered that ant pupae extrude a secretion derived from the molting fluid that is rich in nutrients, hormones, and neuroactive substances. This secretion is consumed by adults, and leads to fungal infections and death of pupae if not removed. Analogous to mammalian milk, the secretion is also an important source of early larval nutrition, and young larvae exhibit stunted growth and decreased survival without access to the fluid. This secretion thus forms the basis of a central and hitherto overlooked interaction network in ant societies.