Social tipping points in animal societies in response to heat stress

Abstract

Living systems sometimes experience abrupt tipping points in response to stress. Here we investigate the factors contributing to the appearance of such abrupt state transitions in animal societies. We first construct a mathematical account of how the personality compositions of societies could alter their propensity to shift from calm to violent states in response to thermal stress. To evaluate our model, we subjected experimental societies of the spider Anelosimus studiosus to heat stress. We demonstrate that both colony size and personality composition influence the timing of and recoverability from sudden transitions in social state. Groups composed of aggressive personalities transitioned into violent within-group dynamics sooner during heating, and also resisted recovery to baseline non-aggressive behaviour during cooling. We further observed hysteresis in groups composed of aggressive individuals, where group behaviour depended strongly on whether the colony had previously been in a calm or agitated state. These results demonstrate that a society's susceptibility to sudden state shifts and their recoverability from them can be driven by the personalities of their constituents.

Homogeneous Symmetrical Threshold Model with Nonconformity: Independence versus Anticonformity

“…On the other hand, hysteresis, which is observed within discontinuous phase transitions, means that under the same external conditions the system can be in a different states depending on its previous states (history). The social hysteresis was observed in animal [49,51,52] as well as in human societies [50,54,55]. The second phenomena, so-called critical mass, which was recently observed experimentally in social convention [53] is also strongly related to the discontinuous phase transitions.…”

“…Is there any reason, other than academic, to distinguish between continuous and discontinuous phase transitions? In the face of the social observations, and more recently also laboratory experiments, it seems that discontinuous phase transitions are particularly important, mainly because of the notion of the social hysteresis and the critical mass [49][50][51][52][53]. Both phenomena are strictly related to discontinuous phase transitions.…”

Assessing the repeatability, robustness to disturbance, and parent–offspring colony resemblance of collective behavior

“…Referring to social groups in this way is less common, but interest in the utility of this viewpoint is growing (Doering et al, ; Flack et al, , ; Pruitt et al, ). Social systems have previously been shown to be vulnerable to shifts from calm to antagonistic states due to the removal of key individuals (in pigtailed macaques, Macaca nemestrina ; Flack et al, ; Flack et al, ) or due to gradual heating (in a subsocial spider, A. studiosus ; Doering et al, ). Meanwhile, simulation studies based on killer whale ( Orcinus orca ) and Columbian ground squirrel ( Spermophilus columbianus ) social groups show that groups are quickly fragmented by the removal of key individuals (Manno, ; Williams & Lusseau, ).…”

“…Discussing populations or ecosystems as "systems" that can exist in different states has a long history in ecology (May, 1974;Solé & Goodwin, 2000). Referring to social groups in this way is less common, but interest in the utility of this viewpoint is growing (Doering et al, 2018;Flack et al, 2006Flack et al, , 2005Pruitt et al, 2018).…”

“…For instance, collective behaviours might be "self-organized," where individuals re-create the same group behaviour after disturbances by following the same set of interaction patterns that created the initial group behaviour (Bonabeau, Theraulaz, Deneubourg, Aron, & Camazine, 1997;Fisher, West, Lomeli, Woodard, & Purcell, 2019). In contrast, groups might change their behaviour following disturbances, if they are shunted into different "states" following a disturbance (Doering, Scharf, Moeller, & Pruitt, 2018;Flack et al, 2006Flack et al, , 2005Pruitt et al, 2018), or engage in nonlinear interactions that give divergent trajectories, and so different group phenotypes, from a similar set of starting conditions (Cole, 1994;Fisher, Brachmann, & Burant, 2018;Honegger & de Bivort, 2018;May & Oster, 1976). However, the robustness of group phenotypes to disturbances is not well documented (but see: Flack et al, 2005Flack et al, , 2006Formica et al, 2016;Kubitza et al, 2015;Smith et al, 2013).…”