Social plasticity in fish: integrating mechanisms and function

Abstract

Social plasticity is a ubiquitous feature of animal behaviour. Animals must adjust the expression of their social behaviour to the nuances of daily social life and to the transitions between life-history stages, and the ability to do so affects their Darwinian fitness. Here, an integrative framework is proposed for understanding the proximate mechanisms and ultimate consequences of social plasticity. According to this framework, social plasticity is achieved by rewiring or by biochemically switching nodes of the neural network underlying social behaviour in response to perceived social information. Therefore, at the molecular level, it depends on the social regulation of gene expression, so that different brain genomic and epigenetic states correspond to different behavioural responses and the switches between states are orchestrated by signalling pathways that interface the social environment and the genotype. At the evolutionary scale, social plasticity can be seen as an adaptive trait that can be under positive selection when changes in the environment outpace the rate of genetic evolutionary change. In cases when social plasticity is too costly or incomplete, behavioural consistency can emerge by directional selection that recruits gene modules corresponding to favoured behavioural states in that environment. As a result of this integrative approach, how knowledge of the proximate mechanisms underlying social plasticity is crucial to understanding its costs, limits and evolutionary consequences is shown, thereby highlighting the fact that proximate mechanisms contribute to the dynamics of selection. The role of teleosts as a premier model to study social plasticity is also highlighted, given the diversity and plasticity that this group exhibits in terms of social behaviour. Finally, the proposed integrative framework to social plasticity also illustrates how reciprocal causation analysis of biological phenomena (i.e. considering the interaction between proximate factors and evolutionary explanations) can be a more useful approach than the traditional proximate-ultimate dichotomy, according to which evolutionary processes can be understood without knowledge on proximate causes, thereby black-boxing developmental and physiological mechanisms.

Transcriptome analyses and differential gene expression in a non-model fish species with alternative mating tactics

“…Phenotypic plasticity has received considerable attention in evolutionary ecology, whereas focus has been laid on long term adaptive phenotypic changes [10,38]. Recent studies, based on model species, which test the more rapid time scale of response to environment such as temperature, light, and presence of pathogens or pheromones [38-40] have demonstrated an important role for protein phosphorylation.…”

Development and application of the adverse outcome pathway framework for understanding and predicting chronic toxicity: I. Challenges and research needs in ecotoxicology

“…The epigenetic contribution is particularly well documented in the context of endocrine disruption (Crews and McLachlan, 2006;Bernal and Jirtle, 2010;Zama and Uzumcu, 2010;Greally and Jacobs, 2013;Svechnikov et al, 2014) as well as in the initiation of cancers (Newbold et al, 2000;Herath et al, 2006;Mirbahai et al, 2011). Moreover, it has also been implicated in many other dysfunctions including disruption of immune (Rodriguez-Cortez et al, 2011;Boehm et al, 2012) and nervous (Oliveira, 2012;Qureshi and Mehler, 2013) systems.…”

Social modulation of brain monoamine levels in zebrafish

“…The high diversity and plasticity of social behaviour among teleost fish makes them excellent models for comparative studies on the mechanisms of social plasticity [22]. In many fish species social systems are characterized by reversible dominance hierarchies, where animals have to adjust the expression of their social behaviour to their perceived social status.…”