The way ants socialize: spit in each other's mouths

Ants have social networks like humans, but instead of exchanging information through email and discussion, they spit on each other.

Most insects have foregut, midgut and hindgut. "however, for social insects, the foregut has become a 'social stomach'." Said Adria LeBoeuf, assistant professor and director of the Social fluid Laboratory at the University of Fribourg in Switzerland. A study led by him shows that the midgut and hindgut are used to digest food, while the foregut is used to share information.

Cross-feeding (the act of feeding food back into the mouth of another creature) is very common in highly gregarious species such as ants. LeBoeuf said that in the phenomenon of interfeeding, nutrients and proteins are transferred from one animal's social stomach to another, and in this way, ants create a "social circulatory system" that connects each member of the group to all other ants.

In this way, wood ants (Camponotus) constantly pass nutrients to each other. If you look at a group, you may see "20 interfeeding phenomena" in a minute, LeBoeuf said. (an ant colony may hold at least thousands of ants. )

As a result, by spitting at each other, ants are not only exchanging nutrients, but are also creating a digestive tract social network where energy and information are recycled throughout the population for collection by ants that need these resources. Much like your brain, it secretes hormones and transmits them to your body's circulatory system, and eventually to your liver.

According to Lebouf, an ant colony is not a collection of individual ants, but a "super organic collective" where the colony operates like a body. Different ant colonies can be thought of as the tissues and organs of superorganisms, which do the work of supporting common goals. Foragers collect food, nannies take care of their young, workers dig tunnels, and so on. Organs use the circulatory system to transmit much more than food, so is it possible for the social circulatory system to transmit more things?

"to help us understand why ants share these liquids, we explored whether the proteins they exchange are related to the role of the individual in the group or the life cycle of the group." Lead author Sanja Hakala, a postdoctoral fellow at the University of Fribourg, said in an article.

In their recent experiment, LeBoeuf and Hakala analyzed the social stomach contents of wild ant colonies and laboratory-raised ant colonies of carpenter ants. In their samples, they identified 519 proteins in the material transferred around the colony, and 27 of these proteins were found in all samples, regardless of the age, location of the population or the status of individual ants.

"usually, the adults in the colony don't even need to eat," LeBoeuf said. "instead, they slowly break down these nutrient-stored proteins."

Many adults in the colony do not have to eat because there are ants to eat instead of the whole colony.

"these findings suggest that some members of the colony can perform metabolic work for the benefit of other ants." Hakala said in an article.

By analyzing where and what proteins were found, LeBoeuf and his colleagues were able to distinguish between young and mature ant colonies and between wild and laboratory-grown colonies. Compared with their wild counterparts, the diversity of proteins in the social stomach of laboratory-cultured ant colonies is much lower.

The team found that the role of an ant in an ant colony is determined by its social stomach contents. Babysitters who take care of young ants tend to have more anti-aging proteins than other members of the colony, perhaps to ensure that they survive to take care of their offspring.

"now we know that nutrients are produced in some ants and eventually passed on to others, which is very exciting," LeBoeuf said. However, there are still many questions to be answered. For example, the team found that foraging ants had higher levels of nutrient protein storage than nanny ants, but nanny ants produced these proteins faster. Researchers are not sure why.

LeBoeuf believes that studying the ant's nutrient exchange system may help scientists better understand how metabolic work is distributed within a single organism, just as it does among the cells that make up the body. "it's hard to measure how metabolic work is shared between cells," LeBoeuf said. "here, ants transmit matter in a way that can easily get what they share."