Effect of intraseptal vasotocin and vasoactive intestinal polypeptide infusions on courtship song and aggression in the male zebra finch (Taeniopygiaguttata)

The present experiments were conducted to test the hypothesis that septal a rginine vasotocin (AVT) and vasoactive intestinal polypeptide (VIP) modulat e directed song (a courtship behaviour) and aggression in male zebra finche s (Taeniopygia guttata). Subjects were surgically fitted with a guide cannu la directed at the septum. Following recovery they were tested for aggressi on and directed song following infusions of AVT, its antagonist (anti-vasop ressin, AVP), and saline Volume control. infusion of the AVT antagonist sig nificantly reduced all three aggressive behaviours measured (pecks, beak fe nces and chases); and AVT infusion significantly facilitated beak fencing. Vasoactive intestinal polypeptide treatment significantly reduced pecking. No treatment produced a change in directed song. Comparison with findings i n mammals suggests that modulation of aggression by septal AVT (or AVP) is evolutionarily conserved in vertebrates, but modulation of aggression by VI P has not previously been reported for any vertebrate.