If you’re having a hard time coping with the isolation this pandemic has imposed on us, find solace in the fact that ants, too, would be just as stressed as you in this situation.

A new paper reports that ants react to social isolation in a similar way to humans and other social species. The most notable changes identified in ants isolated from their groups involve shifts in their social and hygiene behaviors, the team explains. Gene expression for alleles governing the immune and stress response in the brains of these ants were also downregulated, they add.

The burden of loneliness

“[These observed changes] make the immune system less efficient, a phenomenon that is also apparent in socially isolating humans — notably at present during the COVID-19 crisis,” said Professor Susanne Foitzik from Johannes Gutenberg University Mainz (JGU), lead author of the study. The study on a species of ant native to Germany has recently been published in Molecular Ecology.

I don’t think I need to remind you all of this, but humans find social isolation to be a very stressful experience. It can go as far as having a significant and negative impact on our physical health and general well-being. Loneliness, depression, and anxiety can set in quite easily in isolated individuals, they also develop addictions more easily, and their immune system (along with their overall health) takes a hit.

Still, we know much less about how social insects respond to isolation than we do about social animals, including humans. Ants are extremely social insects, living their whole lives in a dense colony and depend on their mates to survive (just like everyone else there). Their lives are so deeply steeped in the social fabric of their colony that worker ants don’t even reproduce, instead caring for the nest and queen, who does all the baby-making. This would be an unthinkable proposition for most other species on Earth.

The team worked with Temnothorax nylanderi, a species endemic to Western Europe. This species lives in cavities formed in fallen plant matter such as acorns or sticks, with colonies usually containing a few dozen workers. The researchers collected young worker ants who were involved in caring for the young from 14 colonies, keeping them in isolation for varying amounts of time. The shortest was one hour, and the longest, 28 days.

After the isolation period, these ants were released back to their colonies. The team explains that these individuals seemed to show lower interest in their adult colony mates, spent less time grooming themselves, but spent more with the brood.

“This reduction in hygienic behavior may make the ants more susceptible to parasites, but it is also a feature typical of social deprivation in other social organisms,” explained Professor Susanne Foitzik.

Gene activity was also impacted. The authors report that a constellation of genes involved in governing the immune system and stress response of these ants was “downregulated”, i.e. less active. This finding is consistent with previous literature showing a weakened immune system after isolation in other social species.

“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,” concludes Foitzik.

The paper “Social isolation causes downregulation of immune and stress response genes and behavioral changes in a social insect” has been published in the journal Molecular Ecology.