Meeting Abstract
The mammalian nonapeptides oxytocin and vasopressin have robust and well-documented effects on social behaviour, while the avian homologues mesotocin and vasotocin also influence social behaviours such as flocking. In fish, however, the effects of the homologous nonapeptides isotocin and vasotocin are less well understood. In this study, we investigated the influence of nonapeptides on grouping behaviour in fish by measuring the time that wild-type guppies (Poecilia reticulata) spent close to a shoal and the time they spent interacting with the shoal after intracerebroventricular administration of isotocin, vasotocin, or putative receptor antagonists. Behaviour was monitored over a period of 2.5 hours after administration, and we found that isotocin significantly increased shoaling behaviour, while vasotocin significantly reduced interactions with the shoal, and that these effects both peaked 1.5 hours after administration. Our study demonstrates clear, and broadly opposing effects of the nonapeptides isotocin and vasotocin on shoaling behaviour. These results show clear similarities with the effects of homologous nonapeptides on grouping and social behaviour in other taxa, and offer support for a conserved role for nonapeptides on vertebrate social behaviour, albeit with species- and taxon-specific variation in the precise behavioural effects. Our results also highlight the importance of measuring the effects of nonapeptides over time rather than only immediately after administration.
