Behavioral diversity and neurochemical plasticity: selection of stress coping strategies that define social status

Social interactions include a variety of stimulating but challenging factors that are the basis for strategies that allow individuals to cope with novel or familiar stressful situations. Evolutionarily conserved strategies have been identified that reflect specific behavioral and physiological identities. In this review we discuss a unique model for social stress in the lizard Anolis carolinensis, which has characteristics amenable to an investigation of individual differences in behavioral responses via central and sympathetic neurochemical adaptation. Profiles of proactive and reactive phenotypes of male A. carolinensis are relatively stable, yet retain limited flexibility that allows for the development of the social system over time. For male A. carolinensis, the celerity of social signal expression and response translate into future social standing. In addition, proactive aggressive, courtship, and feeding behaviors also predict social rank, but are not as important as prior interactions and memories of previous opponents to modify behavioral output and affect social status. The central neurotransmitters dopamine and serotonin, and the endocrine stress axis (HPA) appear to be the fundamental link to adaptive stress coping strategies during social interactions. Only small adaptations to these neural and endocrine systems are necessary to produce the variability measured in behavioral responses to stressful social interactions. These neuroendocrine factors are also manifest in responses to other stimuli and form the basis of heritable strategies for coping with stress.