Trinidadian guppies use a social heuristic that can support cooperation among non-kin

Abstract

Cooperation among non-kin is well documented in humans and widespread in non-human animals, but explaining the occurrence of cooperation in the absence of inclusive fitness benefits has proven a significant challenge. Current theoretical explanations converge on a single point: cooperators can prevail when they cluster in social space. However, we know very little about the real-world mechanisms that drive such clustering, particularly in systems where cognitive limitations make it unlikely that mechanisms such as score keeping and reputation are at play. Here, we show that Trinidadian guppies ( Poecilia reticulata ) use a ‘walk away’ strategy, a simple social heuristic by which assortment by cooperativeness can come about among mobile agents. Guppies cooperate during predator inspection and we found that when experiencing defection in this context, individuals prefer to move to a new social environment, despite having no prior information about this new social group. Our results provide evidence in non-human animals that individuals use a simple social partner updating strategy in response to defection, supporting theoretical work applying heuristics to understanding the proximate mechanisms underpinning the evolution of cooperation among non-kin.

Exploring the causes and consequences of cooperative behaviour in wild animal populations using a social network approach

“…Captive rats ( Rattus norvegicus ), capuchin monkeys ( Cebus apella ), and dogs ( Canis familiaris ) have been shown to engage in generalised reciprocity when tested on a cooperative task requiring the pulling of a stick or rope which presents food to their partner (Rutte & Taborsky, 2007; Leimgruber et al ., 2014; Gfrerer & Taborsky, 2017). In a more recent study (Darden et al ., 2020), a predator inspection arrangement was used to explore cooperation in Trinidadian guppies ( Poecilia reticulata ), showing that individuals would either stay with or switch their social partner on the basis of whether the partner had cooperated or defected in their most recent interaction (see Section I.3).…”

Social partner cooperativeness influences brainoxytocintranscription in Trinidadian guppies (Poecilia reticulata)

“…Given the proposed role of Oxt in the regulation of the salience of social stimuli in a context-dependent manner via the regulation of attention to social cues [54], it is also possible that the observed oxt transcription patterns represent a role the higher propensity for individuals to remember characteristics associated with cheaters compared to cooperators, a bias that has for example been demonstrated in humans [55]. This could be explained by the possibility that information regarding ‘cheating’ is more important when predicting trait characteristics of social partners, and therefore their future behaviour [56,57]; that is ‘negative’ cues can potentially be more diagnostic than ‘positive’ ones [57,58]. Indeed the most recent work in this species would suggest that female guppies are most socially selective following social partner defection compared to cooperation [58].…”

“…This could be explained by the possibility that information regarding ‘cheating’ is more important when predicting trait characteristics of social partners, and therefore their future behaviour [56,57]; that is ‘negative’ cues can potentially be more diagnostic than ‘positive’ ones [57,58]. Indeed the most recent work in this species would suggest that female guppies are most socially selective following social partner defection compared to cooperation [58]. More work is needed to gain a better understanding of both the role of Oxt in behaviour in this cooperative context and in subsequent decision-making.…”

Brain monoaminergic activity during predator inspection in the Trinidadian guppy (Poecilia reticulata)

“…12,13] or to continue or not any particular social affiliation [e.g. 14,15]. Unravelling the mechanistic underpinnings of the appraisal of the social environment will provide insight into cooperative decision-making processes and ultimately the rules and strategies that maintain cooperation among unrelated individuals.…”

“…Predator inspection is considered a model for the study of cooperation [45], as all shoal members benefit from the information gathered, irrespective of whether they inspected or not. Previous work suggests that brain nonapeptide production [46] and downstream behaviours [15, 47] are measurably affected by the previous experience of the cooperative acts of others. We experimentally manipulated the ostensible experience of cooperation or defection from the social environment, and then measured the brain levels of DA, 5-HT, and their metabolites.…”