Oral fluid exchanged between ants contains molecules that the insects might use to communicate.
Ants were generally thought to share only nutrients and enzymes through a mouth-to-mouth feeding process called trophallaxis. But when Adria LeBoeuf at the University of Lausanne in Switzerland and her co-workers analysed the oral liquid of the species Camponotus floridanus, they found 64 microRNAs, 49 long-chained hydrocarbons, a hormone that regulates growth and more than 50 proteins involved in development, digestion and immunity.
The hydrocarbons could contribute to a characteristic colony odour, and the hormone may influence larval growth and development. When the team added the hormone to the food of worker ants, more than twice as many of the larvae they reared reached adulthood, compared with those that were not exposed. The findings suggest that trophallaxis facilitates communication and helps the colony to develop, the authors say.