Seasonal and social factors associated with spacing in a wild territorial electric fish.
Lucía Zubizarreta, Laura Quintana, Daniel Hernández, Franco Teixeira de Mello, Mariana Meerhoff, Renato Massaaki Honji, Renata Guimarães Moreira, Ana Silva
Author Information
Lucía Zubizarreta: Laboratorio de Neurofisiología Celular y Sináptica, Departamento de Fisiología, Facultad de Medicina, Universidad de la República, Montevideo, Uruguay.
Laura Quintana: Unidad Bases Neurales de la Conducta, Departamento de Neurofisiología Celular y Molecular, Instituto de Investigaciones Biológicas Clemente Estable, Montevideo, Uruguay.
Daniel Hernández: Laboratorio de Control Ambiental, Polo Educativo Tecnológico Arrayanes, CETP-UTU, Maldonado, Uruguay.
Franco Teixeira de Mello: Departamento de Ecología y Gestión Ambiental, Centro Universitario Regional del Este, Universidad de la República, Maldonado, Uruguay.
Mariana Meerhoff: Departamento de Ecología y Gestión Ambiental, Centro Universitario Regional del Este, Universidad de la República, Maldonado, Uruguay.
Renato Massaaki Honji: Centro de Biologia Marinha, Rodovia Manoel Hipólito do Rego, Universidade de São Paulo (CEBIMar/USP), São Sebastião, SP, Brazil. ORCID
Renata Guimarães Moreira: Departamento de Fisiologia, Instituto de Biociências, Universidade de São Paulo, Rua do Matão, São Paulo, SP, Brazil.
Ana Silva: Unidad Bases Neurales de la Conducta, Departamento de Neurofisiología Celular y Molecular, Instituto de Investigaciones Biológicas Clemente Estable, Montevideo, Uruguay. ORCID
In this study, we focused on the seasonal variation of the determinants of territory size in the weakly electric fishGymnotus omarorum. This species is a seasonal breeder that displays year-round territorial aggression. Female and male dyads exhibit indistinguishable non-breeding territorial agonistic behavior and body size is the only significant predictor of contest outcome. We conducted field surveys across seasons that included the identification of individual location, measurements of water physico-chemical variables, characterization of individual morphometric and physiological traits, and their correlation to spatial distribution. G. omarorum tolerates a wide range of dissolved oxygen concentration, and territory size correlated positively with dissolved oxygen in both seasons. In the non-breeding season, territory size was sexually monomorphic and correlated only with body size. In the breeding season, territory size no longer correlated with body size but differed between sexes: (i) the overall spatial arrangement was sexually biased, (ii) territory size depended on gonadal hormones in both sexes, which was expected for males, but not previously reported in females, (iii) female territory size showed a positive relationship with gonadal size, and (iv) females showed relatively larger territories than males. This study demonstrates seasonal changes in the determinants of territory size and thus contributes to the understanding of the mechanisms underlying the behavioral plasticity natural territorial behavior.
