title: A multidisciplinary study on social status and the relationship between inter-individual variation in hormone levels and agonistic behavior in a Neotropical cichlid fish.
abstract: Social animals with hierarchal dominance systems are particularly susceptible to their social environment. There, interactions with conspecifics and hierarchal position can greatly affect an individual's behavior, physiology and reproductive success. Our experimental model, Cichlasoma dimerus, is a serially-monogamous Neotropical cichlid fish with a hierarchical social system, established and sustained through agonistic interactions. In this work, we aimed to describe C. dimerus social structure and its association with hormonal profiles and testicular cellular composition. We recorded and quantified agonistic interactions from the territorial pair, i.e. the top ranked male and female, and the lowest ranked male of stable social groups. Plasma levels of 11-ketotestosterone (11-KT), testosterone, 17β-estradiol (E2) and cortisol were measured by ELISA. Results show that territorial pairs cooperatively guarded the territory, but rarely attacked in synchrony. Territorial males had higher testosterone and 11-KT plasma levels than non-territorial males, while E2 and an index of its metabolization from testosterone were higher in non-territorial males. No difference was observed in cortisol levels. Plasma 11-KT and an index of the conversion of testosterone to 11-KT, positively correlated with the frequency of aggressiveness, while E2 showed the opposite pattern. Territorial males had a higher gonadosomatic index than non-territorial males. The quantification of testicular cellular types revealed that the percentage of spermatocytes and spermatids was higher in non-territorial males, while territorial males showed a greater percentage of spermatozoa. Thus, C. dimerus male social position within a stable hierarchy is associated with distinct behaviors, steroid levels and testicular degree of development.
authors: Instituto de Biodiversidad y Biología Experimental y Aplicada - CONICET, Ciudad Autónoma de Buenos Aires, Argentina; Laboratorio de Neuroendocrinología y Comportamiento, Departamento de Biodiversidad y Biologia Experimental, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Ciudad Autónoma de Buenos Aires, Argentina.
authors: Martín R
authors: MR
authors: Ramallo
authors: Laboratorio de Neuroendocrinología y Comportamiento, Departamento de Biodiversidad y Biologia Experimental, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Ciudad Autónoma de Buenos Aires, Argentina.
authors: Agustina
authors: A
authors: Birba
authors: Departamento de Fisiologia, Instituto de Biociências, Universidade de São Paulo, Rua do Matão, Trav. 14 n°321, Cidade Universitária, São Paulo 05508-090, Brazil.
authors: Renato M
authors: RM
authors: Honji
authors: Instituto de Biodiversidad y Biología Experimental y Aplicada - CONICET, Ciudad Autónoma de Buenos Aires, Argentina; Laboratorio de Neuroendocrinología y Comportamiento, Departamento de Biodiversidad y Biologia Experimental, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Ciudad Autónoma de Buenos Aires, Argentina.
authors: Leonel
authors: L
authors: Morandini
authors: Departamento de Fisiologia, Instituto de Biociências, Universidade de São Paulo, Rua do Matão, Trav. 14 n°321, Cidade Universitária, São Paulo 05508-090, Brazil.
authors: Renata G
authors: RG
authors: Moreira
authors: Laboratorio de Ictiofisiología y Acuicultura, Instituto de Investigaciones Biotecnológicas-Instituto Tecnológico de Chascomús (IIB-INTECH. CONICET-UNSAM), Chascomús, Argentina.
authors: Gustavo M
authors: GM
authors: Somoza
authors: Instituto de Biodiversidad y Biología Experimental y Aplicada - CONICET, Ciudad Autónoma de Buenos Aires, Argentina; Laboratorio de Neuroendocrinología y Comportamiento, Departamento de Biodiversidad y Biologia Experimental, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Ciudad Autónoma de Buenos Aires, Argentina. Electronic address: pandolfi@bg.fcen.uba.ar.
authors: Matías
authors: M
authors: Pandolfi
mesh_terms: D000374:Aggression / Q000502:physiology; D000378:Agonistic Behavior; D000818:Animals; D023681:Cichlids / Q000097:blood / Q000502:physiology; D004958:Estradiol / Q000097:blood*; D005260:Female; D006608:Hierarchy, Social; D006854:Hydrocortisone / Q000097:blood*; D007206:Individuality; D008297:Male; D012098:Reproduction / Q000502:physiology; D012931:Social Environment; D013731:Territoriality; D013739:Testosterone / Q000031:analogs & derivatives* / Q000097:blood*
chemical_list: D013739:Testosterone; D004958:Estradiol; C003600:11-ketotestosterone; D006854:Hydrocortisone
keywords: 17β-Estradiol; Aggression; Agonistic behavior; Androgens; Cichlasoma dimerus; Cichlids; Cooperative behavior; Cortisol