Cortisol Coregulation in the Monogamous Convict Cichlid, Amatitlania nigrofasciata

Shared experiences and social bonds have been shown to synchronize aspects of both behavior and the endocrine system between individuals. This has been demonstrated in humans and has been theorized to be reflected in other vertebrates. The term coregulation is often used to describe the influence of social interactions on physiological responses and behavior. In the present experiment, we test stress induced endocrine coregulation in the monogamous convict cichlid, Amatitlania nigrofasciata. In fish, cortisol (the primary stress hormone) is released by the hypothalamic-pituitary-interrenal (HPI) axis when a real or perceived stressor is recognized by the central nervous system. This can cause a corresponding behavioral stress response that can include freezing, wall hugging, or affiliative behavior. The convict cichlid is an ideal species to study endocrine coregulation due to their complex social behavior. The social relationships they are capable of forming can enhance the likelihood of hormone synchronization. Using two models, unmated pairs underwent a standardized stressor; stressed individuals then recovered either together or separately. Our aim is to determine whether cortisol levels between stressed pairs who recovered together will be correlated, and the degree to which behavior can explain the correlation. We predict that stressed pairs who recover together will show correlated cortisol levels, while stressed pairs who recover separately will not display this coregulated relationship. Further, we predict that the amount of time spent together during the recovery period will correlate with the degree of hormonal similarity.