WHEN ANTS GET CLOSE…WHAT DO THEY EXCHANGE?

Ants are social insects, well known for their division of labor and caste systems, as well as their hardworking nature. They have also inspired popular culture, including sayings (“ants in your pants”), music (see “Ants marching” and “El hormiguero”), and jewelry. However, there is one curious behavior that is largely unknown to the general public (and even to many scientists) called trophallaxis, in which ants ingest liquid shared by another individual! This can occur in two different ways: as a regurgitate coming from the mouth, called stomodeal trophallaxis, or as an excretion from the rectal end of the abdomen, called proctodeal trophallaxis. Trophallaxis also occurs in earwigs, burying beetles, birds, and mammals, but we will focus on ants, an extensively studied group. 

In a comprehensive review, Meurville & LeBoeuf (2021) describe how within ant colonies, trophallactic behavior occurs in multiple directions …