Meeting Abstract
Julidochromis transcriptus, demonstrates conventional sex-biased parental and aggressive behaviors (i.e. males are more aggressive than females), whereas their close relative, Julidochromis marlieri, exhibits reversed sex-biased behaviors (i.e. females are more aggressive than males). Arginine vasotocin (AVT; the non-mammalian homolog to arginine vasopressin) and isotocin (IT; the non-mammalian homolog to oxytocin), are associated with reproductive plasticity, aggression, and other social behaviors. It is unknown whether the proportion of active AVT and IT cells is associated with aggression or dominance within sex-biased mating pairs in these species. I hypothesized that there would be more active AVT expressing cells in aggressive relative to non-aggressive individual’s brains because AVT is associated with aggressive behaviors in some teleost species. To test this hypothesis, I recorded behavioral observations of mated pairs for both cichlid species, sectioned their brains, and performed immunohistochemistry (by triple labeling with AVT, IT, and Phosphorylated Serine 6 (PS6) antibodies) to quantify the number of active and non-active AVT and IT expressing cells. PS6 was used to indicate translational activity and was found to be more effective at measuring current cell activity than an immediate early gene. There were significantly more PS6 positive (+) IT neurons in the aggressive individuals (i.e.J. transcriptus males and J. marlieri females) relative to non-aggressive individuals (i.e. J. transcriptus females and J. marlieri males) (p=0.0211). The same pattern is true for both PS6 negative IT neurons (p=0.00946) and AVT neurons (p=0.0133), but no significant difference was found for the number of PS6+ AVT neurons. These results suggest that IT neuron activity may influence aggressive behaviors in J. transcriptus and J. marlieri.
