Ants react to social isolation in a similar way as do humans and other social mammals. A new study has revealed alterations to the social and hygienic behavior of ants that had been isolated from their group. The research team was particularly surprised by the fact that immune and stress genes were down-regulated in the brains of the isolated ants.
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“This makes the immune system less efficient, a phenomenon that is also apparent in socially isolating humans — notably at present during the COVID-19 crisis.”
-Professor Susanne Foitzik, researcher, Johannes Gutenberg University Mainz (JGU)
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Backstory
Humans and other social mammals experience isolation from their group as stressful, having a negative impact on their general well-being and physical health. “Isolated people become lonely, depressed, and anxious, develop addictions more easily, and suffer from a weakened immune system and impaired overall health,” said Professor Inon Scharf, lead author of the article and cooperation partner of the Mainz research group at Tel Aviv University in Israel. While the effects of isolation have been extensively studied in social mammals such as humans and mice, less is known about how social insects respond in comparable situations — even though they live in highly evolved social systems. Ants, for instance, live their entire lives as members of the same colony and are dependent on their colony mates. The worker ants relinquish their own reproductive potential and devote themselves to feeding the larvae, cleaning and defending the nest, and searching for food, while the queen does little more than just lay eggs.
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Study overview
The research team looked at the consequences of social isolation in the case of ants of the species Temnothorax nylanderi. These ants inhabit cavities in acorns and sticks on the ground in European forests, forming colonies of a few dozen workers. Young workers engaged in brood care were taken singly from 14 colonies and kept in isolation for varying lengths of time, from one hour to a maximum of 28 days. The study was conducted between January and March 2019 and highlighted three particular aspects in which changes were observed. After the end of their isolation, the workers were less interested in their adult colony mates, but the length of time they spent in brood contact increased; they also spent less time grooming themselves.
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Results overview
Stress due to isolation adversely affects the immune system
While the study revealed significant changes in the behaviors of the isolated insects, its findings with regard to gene activity were even more striking: Many genes related to immune system function and stress response were down-regulated. In other words, these genes were less active.
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“Our study shows that ants are as affected by isolation as social mammals are and suggests a general link between social well-being, stress tolerance, and immunocompetence in social animals.”
-Professor Susanne Foitzik, researcher, Johannes Gutenberg University Mainz (JGU)
Journal reference: Inon Scharf, Marah Stoldt, Romain Libbrecht, Anna Lena Höpfner, Evelien Jongepier, Marion Kever, Susanne Foitzik. Social isolation causes down-regulation of immune and stress response genes and behavioral changes in a social insect. Molecular Ecology, 2021; DOI: 10.1111/mec.15902
