Meeting Abstract

P2.186  Saturday, Jan. 5  Brain Development of Amatitlania nigrofasciata and the Onset of Aggressive and Territorial Behaviors KATAGI, A*; DRAUD, M; SANTAGATA, S; Long Island University-Post, Brookville ayakokatagi@hotmail.com

Animals often secure resources, such as food and mates, through the expression of a suite of behavior collectively referred to as aggression. Aggressive behaviors are likely finely honed by evolution because of their impact on lifetime reproductive success. Fishes in the family Cichlidae are a prominent example of animals that exhibit aggressive behavior. We used the convict cichlid, Amatitlania nigrofasciata, as a model species to study the role of brain development and brain growth in the ontogeny of conspecific aggressive behaviors. Our behavioral experiments were based on the responses of a resident fish to a new intruder. We measured the growth of developing brain regions in embryos, larvae, and juvenile fish with epifluorescence and light microscopy using image analysis software. We then explored how changes in brain development and growth correlated with the onset of rudimentary aggressive behaviors (poking and biting), coordinated aggressive behaviors (tail beating and mouth wrestling), and territorial behaviors (approach and territory entry). Although not previously documented for juvenile stages, the resident fish’s simple aggressive behaviors towards intruders began immediately after the wiggling stage, when the fry (6 mm) become able to swim. More advanced (adult-like) aggressive behaviors such as tail beating and mouth wrestling were also observed in juvenile fish and become more complex in juveniles 2 cm in length. Of the seven measured brain regions, growth of the cerebellum, and, more notably, the telencephalon are best positively correlated with the onset of territorial behaviors and both categories of aggressive behaviors in convict cichlids.