Marian Wong completed her BA in Zoology from the University of Cambridge, U.K. and then went on to conduct her PhD in Marine Biology at James Cook University under the supervision of Drs. Philip Munday and Geoff Jones. Her current research focuses on understanding the evolution of social and reproductive behaviour using fishes as model organisms. During her PhD, she used the coral-dwelling goby, Paragobiodon xanthosomus, to test key hypotheses for the evolution of monogamy, group-living and conflict resolution, using experimental techniques. Currently, she is based at McMaster University in Hamilton, Canada where she is collaborating with Dr. Sigal Balshine in investigating various aspects of the social and reproductive behaviour of the African cichlid fish, Neolamprologus pulcher. This fascinating species exhibits a complex social system which makes it ideal for testing a broad range of theories for the evolution of cooperative behaviour, social aggression and the formation and maintenance of dominance relationships, as well as the molecular correlates of social behaviour.
Social queues, in which subordinates wait their turn to inherit dominant breeding status, are a familiar feature of many animal societies. However, little is known of the mechanisms stabilising social queues given the inevitable conflict over rank between group members. Here we report the role of punishment and cooperation in promoting the stability of size-based queues in a coral-dwelling goby, Paragobiodon xanthosomus (Gobiidae). Quantitative analysis of the size-structure of queues revealed that individuals of adjacent rank differ in size by a specific size ratio, and comparisons of individual growth rates within queues demonstrated that specific size ratios are maintained over time via the regulation of subordinate growth rates. Furthermore, contest experiments demonstrated that the specific size ratio represents a threshold above which subordinates become a threat to their immediate dominant, and as a result, dominants evict subordinates that exceed this size ratio from the group. We propose that threshold size ratios are maintained by subordinates as a form of peaceful cooperation whereby they avoid inflicting costs on dominants, and that such cooperation arises in response to the threat of punishment in the form of eviction by dominants. Societal stability is therefore achieved through the effects of punishment and cooperation acting in concert to promote the resolution of conflict over rank between group members.