The social transmission of stress in animal collectives

Abstract

The stress systems are powerful mediators between the organism's systemic dynamic equilibrium and changes in its environment beyond the level of anticipated fluctuations. Over- or under-activation of the stress systems' responses can impact an animal's health, survival and reproductive success. While physiological stress responses and their influence on behaviour and performance are well understood at the individual level, it remains largely unknown whether—and how—stressed individuals can affect the stress systems of other group members, and consequently their collective behaviour. Stressed individuals could directly signal the presence of a stressor (e.g. via an alarm call or pheromones), or an acute or chronic activation of the stress systems could be perceived by others (as an indirect cue) and spread via social contagion. Such social transmission of stress responses could then amplify the effects of stressors by impacting social interactions, social dynamics and the collective performance of groups. As the neuroendocrine pathways of the stress response are highly conserved among vertebrates, transmission of physiological stress states could be more widespread among non-human animals than previously thought. We therefore suggest that identifying the extent to which stress transmission modulates animal collectives represents an important research avenue.

Mind body medicine: a modern bio-psycho-social model forty-five years after Engel

“…Interesting new research in the social transmission of stress in animal collectives may offer us a framework for understanding this cumulative societal inverted U-shaped curve [ 131 ]. There is now sufficient evidence to suggest that stress transmission is widespread across vertebrates and this may be especially true among mammals given our social attachment survival strategy.…”

Behavioural ecology at the spatial–social interface

“…An individual's social and spatial phenotypes may be correlated because the spatial phenotype determines the way an individual engages with its environment and the social phenotype is influenced by these environmental gradients. For example, an individual exposed to an environmental stressor, such as a predator, could transmit this ‘stress’ to its social associates (Brandl, Pruessner & Farine, 2022), and subsequently impact their choice to forage in risky habitat. Additionally, relationships between social and spatial phenotypes may be produced by shared intrinsic drivers, like reproductive state, that affect both (Saveer et al ., 2012).…”

Social buffering of the stress response: insights from fishes

“…visual, chemical) with a stressed conspecific. Although most studies have focused on mammals, primarily humans [70], there is also evidence of social transmission of stress in fishes [33,[71][72][73]. For example, visual exposure to a predatory fish evoked a cortisol response in zebrafish that viewed the predator, but also in zebrafish that did not view the predator but observed only the zebrafish that were exposed to the predator [71].…”

“…One possibility is that social buffering serves as a check on the social transmission of stress [ 70 ]. Social transmission of stress occurs when an individual animal that has not been exposed to a stressor exhibits behavioural and physiological stress responses through contact (e.g.…”

“…Social transmission of stress may be useful, for instance in signalling the existence of a threat in the environment, but also has the potential to be maladaptive, if it leads, for example, to inappropriate amplification or prolongation of a stress response. By countering social transmission, social buffering may serve to avoid such maladaptive situations [ 70 ].…”