Dominance and subordination: how fish control their access to reproduction?

MATÍAS PANDOLFI; MARTÍN ROBERTO RAMALLO; LEONEL MORANDINI; FELIPE ALONSO; AGUSTINA BIRBA

Huerta Grande, Córdoba

Congreso; XXVIII Congreso Anual de la Sociedad Argentina de Investigación en Nuerociencias & Reunión Satélite/Neurobiología; 2013

Social interactions with the outcome of a position in a dominance hierarchy can have profound effects on reproductive behavior and physiology. Cichlid fish (Perciformes) are intensively studied in the field of social control of reproduction. The most studied species to date have been Astatotilapia burtoni from Tanganika Lake and the tilapia Oreochromis mossambicus. We are studying New World cichlids using the South American cichlid Cichlasoma dimerus (â?oechanchitaâ?) as a biological model. This substrate breeding fish has biparental care of the fry and presents a dominance hierarchy that determines access to breeding territories among males, and to males with territories among females. Female and male individuals who were located on the top rank of the social hierarchy, ascended in social status when the opportunity arose, therefore indicating that dominance is directly correlated with social ascent likelihood. Dominance was positively correlated with size in males but not in females, suggesting for the latter a relationship with intrinsic features such as aggressiveness or personality rather than to body and/or ovarian size. In order to perform these studies we developed different tools that will be presented: histological atlas from brain, gonads and different endocrine glands (pituitary gland, pineal complex and interrenal gland), ethograms, characterization of genes involved in behavior, stress and reproduction. Using all this information together we try to understand how social interactions control fish access to reproduction. Also we are trying to obtain useful information in order to improve the culture of cichlid fish that are economically relevant for our country.