The evolution of sociality in habitat-specialist coral reef fish: exceptions that prove the rule?

A project undertaken at the School of Biological Sciences, University of Wollongong and supervised by Marian Wong and Mark Dowton

While some species are social, others remain stubbornly asocial, and this contrasting variation often seen between closely related species has long puzzled evolutionary biologists. Why should some species live in permanent groups whereas others live asocial existences? Identifying the causes of such variation is important because it enables us to determine what factors underlie the remarkable diversity of social systems exhibited by life on earth. The aim of our project is to use broad comparative phylogenetic analysis coupled with field observations and experiments to test multiple hypotheses for sociality. We are focusing our investigations on a speciose yet neglected group of study organisms, habitat-specialist coral reef fishes, and our fieldwork is based at Lizard Island, QLD. These cryptic species form integral components of coral reef biodiversity, living their entire lives within the confines of coral colonies. They display a remarkable diversity of social systems, with some species being pair-forming and others forming large complex groups, which makes them ideal for performing our investigations.

Figure 1. Lizard Island (Photo:Marian Wong)

Figure 2. Diver and corals (Photo: Selma Klanten)

Figure 3. One of the target species under investigation, Paragobiodon xanthosomus (Photo: João Paulo Krajewski)