We are social beings – it is well known that loneliness is not good for us. Apparently this also applies to ants, according to a study: The insects react to isolation in a strikingly similar way to humans or social mammals. As a result of isolation, ants develop certain behavioral problems and tend to care less for themselves. The researchers also found genetic evidence of impaired stress regulation and a weakened immune system. The results suggest a fundamental connection between social well-being, stress tolerance and health in social organisms, say the scientists.
Many studies prove the negative effects and in the context of the corona pandemic, the consequences of social isolation are becoming particularly clear: Many people react stressed and their physical and mental condition can be damaged. “Isolated people get feelings of loneliness, become depressed and anxious, develop addictions more easily and suffer from a weakened immune system and impaired health in general”, Inon Scharf from Johannes Gutenberg University Mainz summarizes the possible consequences.
It is also well known that many social animal species suffer similarly when kept in “solitary confinement”. The effects of isolation have already been studied in detail, especially in mammalian species such as mice. But little is known about the reactions of socially living insects, say Scharf and his colleagues. That is why they have now devoted a study on the subject to the ants.
How do ants react to “solitary confinement”?
These insects are known for their complex social behaviors and systems: they spend their entire lives as part of their colony, depending on its members. The workers give up their own reproductive potential and take care of feeding the larvae, cleaning and defending the nest and looking for food, while the queen almost exclusively lays eggs. For these animals, the “we” is in the foreground and a complex interaction behavior between the individuals is necessary for the functioning of the community. This also applies to the ants that Scharf and his colleagues selected for their studies. It was the species Temnothorax nylanderi, which is native to the forests of Europe.
To isolate individual animals, the researchers took 14 test colonies of young workers and kept them separated from their group members for a few days. These quadrupeds were then released back into their colonies and the scientists recorded the behavior of the tagged individuals. As they report, the “solitary confinement” had a clear impact on the ants: after the end of the isolation, they interacted less intensively with their adult nestmates than is usually the case. In return, however, they were unusually interested in contact with the colony’s brood, the researchers report. A particularly noticeable effect was that the ants, characterized by loneliness, became neglected: They spent comparatively little time caring for their own bodies. “This change in hygiene behavior could make the ants more susceptible to parasites,” says senior author Susanne Foitzik from Johannes Gutenberg University Mainz.
Genetic evidence of weaknesses
In addition to the behavioral analyzes, the scientists also examined the changes in the activity of genes in the brain of the test animals. To do this, they recorded the so-called transcriptome in the brain tissue of the isolated individuals and compared it with that of control animals. It was shown that many genes, which are known to have functions in connection with the control of stress reactions and especially for the immune system, showed reduced activity. “This suggests that the immune system in these ants is less efficient, which we also see as a result of social isolation in humans – especially now in times of Covid-19,” says Foitzik. Her colleague Scharf adds: “The result also matches studies with other social animals that show a weakened immune system after isolation”.
As the scientists point out, they have now for the first time presented a study on the effects of isolation in social insects that combines behavior and genetic analyzes. “It shows that ants are just as affected by isolation as other social organisms and suggests a general relationship between social well-being, stress tolerance and immune competence in social animals,” says Foitzik, summarizing the significance of the results.
Source: Johannes Gutenberg University Mainz, specialist article: Molecular Ecology, doi: 10.1111 / mec.15902