Social immunity and resilience: Lessons from the world of insects

Introduction

I have been always fascinated by the social behavior of ants and bees. Their capacity to adapt and create sustainable colonies in the most disparate environments has demonstrated a major differentiator among other species where the social collaboration has not been developed.

During these past weeks of lockdown, I have been rediscovering some books dedicated to the social insects and their organizations with clearly defined roles and rules for each individual. The parallel with our human organizations and societies is far too complex and different, but the social insects’ responses to crisis situations has some aspects that, I think, deserve attention.

The current COVID-19 pandemic emergency raises a number of unexpected risks and unprepared reaction strategies that we have to consider and re-evaluate for future crisis situations. Some positive learnings can be shared by the social insects, and especially by the colonies’ behavior of ants, bees and termites. They have been demonstrated and are recognized as the more resilient social organisms, able to adapt to extremely hard environments and to react to disruptive crisis situations.

The defenses of a colony against a wide range of predators, parasites and pathogens have been the subject of innumerable researches, but it is only recently, that certain phenomena have begun to be considered, looking at them in an integrated perspective of the colonial response, rather than as the sum of reactions of single individuals. This can be explained by the fact that the individual immune system is partly substituted by the social one. The basic idea is that, by acting collectively, the individuals of a colony can put in place a more effective defense.

Similarly, our reaction to pandemic crisis should be driven by collective procedures and practices that have to be enforced among different individuals. The current COVID crisis forced, probably for the first time in history, a worldwide reaction and coordinated response, imposing the lockdown, social distance, health procedures and security controls that impacted the entire human race, independently by the country or wealth.

Unfortunately, our global reaction was not strictly coordinated and fast like the one social insects are able to apply. If you look at the reaction to external attacks to an ant’s nest, a beehive or a termite nest, you will find the amazing and immediate collaboration and sacrifice of many individuals to protect their colony.

These social immune defenses include both mechanisms that increase the prevention of disease transmission, and mechanisms that are activated when pathogens have already invaded the colony. In any case, the common feature of all these defense mechanisms is that they are based on altruistic behavior or collective actions that provide advantages at the colony level and, only rarely, for the individual. As a consequence, the social immune system can be understood and explained as a group level adaptation.

The mechanism of social immunity develops mainly at two different levels, the first, which we could define as “preventive”, includes all those strategies that tend to keep any parasites and pathogens out of the nest. For example, in a hive, the guardian bees represent the first filter to prevent the entry of parasites and pathogens into the colony.

The second common strategy of social insects could be defined as “restoring” that contributes to creating a real sanitary cordon around the colony is that of the disposal of waste and corpses. This phenomenon is particularly evident in ants which, in some species, constitute real landfills and cemeteries.

I would like to summarize the concepts that can be derived by the social insects’ behaviors to enhance our response capacity to crisis situations:

• Procedures: pre-established reaction procedures, risk assessment on different possible predators
• Prevention:  teaching and testing enforced to all individuals, clear assigned roles, multiple levels of defense
• Reaction:  immediate, joint effort and response, collaboration of multiple individuals to a single objective

It sounds like a governance and risk process well established in a cooperative organization where the end result ensures resilience and sustainability of the entire colony.

I would like to thank some ideas extracted from “Le politiche degli insetti” di Stefano Turillazzi, Edizioni ETS.