Building the case for a novel teleost model of non-breeding aggression and its neuroendocrine control. Issue 3 (October 2016)

• Record Type: Journal Article
• Authors: Quintana, Laura; Zubizarreta, Lucía; Jalabert, Cecilia; Batista, Gervasio; Perrone, Rossana; Silva, Ana
• Is Part Of: Journal of physiology -Paris. Volume 110:Issue 3(2016)Part B
• Page Start: 224
• Page End: 232
• Publication Date: 2016-10
• Subjects: Agonistic behavior -- Territorial aggression -- Submission signals -- Estradiol -- Aromatase -- Gonadal steroids -- Female aggression -- Electric fish -- Gymnotus omarorum; Physiology -- Periodicals; 571.105
• DOI: 10.1016/j.jphysparis.2016.11.009
• Languages: English
• ISSNs: 0928-4257

Abstract

Highlights: Gymnotus omarorum displays robust intrasexual aggression in the non-breeding season. Subordination is influenced by size asymmetry and also aggression levels of dominants. Female aggression shows no difference with male aggression. This non-breeding aggressive behavior is independent of gonadal hormones. However it depends on the estrogenic pathway, as aromatase plays a key role. Abstract: In vertebrates, aggression has been traditionally associated with high levels of circulating androgens in breeding males. Nevertheless, the centrality of androgens as primary modulators of aggression is being reconsidered in at least in two particular cases: (1) territorial aggression outside the breeding season, and (2) aggression by females. We are developing the weakly electric fish, Gymnotus omarorum, as a novel, advantageous model system to address these two alternative forms of aggression. This species displays a short, escalated contest, after which a clear hierarchical status emerges. Subordination of individuals involves three sequential decisions: interruptions of their electric discharges, retreats, and chirps. These decisions are influenced by both size asymmetry between contenders and aggression levels of dominants. Both females and males are aggressive, and do not differ in fighting ability nor in the value placed on the resource. Aggression is completely independent of gonadal hormones: dominance status is unrelated to circulating androgen and estrogen levels, and gonadectomy in males does not affect aggression. Nevertheless, estrogenic pathways participate in the modulation of this non-breeding aggression. Our results parallel those put forth in other taxa, heightening the value of G. omarorum as a model to identify commonalities in neuroendrocrine strategies of vertebrate aggression control.