Social and Reproductive Behavior of Chaetodontoplus mesoleucus (Pomacanthidae) at Bantayan Island, Philippines, with Notes on Pomacanthid Relationships

Abstract

Chaetodontoplus mesoleucus occurs at Bantayan Island in a habitat of small patches of mixed scleractinian and alcyonacean corals of low diversity and simple structure. Male-female pairs were predominant, and the sex-ratio showed only a slight skew towards females. However, the presence of single male, two-female social groups demonstrates that the species is polygamous. Small size of social groups is attributed to a preference for a habitat lacking structural complexity. The species did not occur on complex coral reefs. Social and spawning behavior are nearly identical to that of most pomacanthids for which data are available, and although sex-change was not demonstrated, size-related dominance hierarchies and close phylogenetic relationships to sex-changing pomacanthids suggest protogynous hermaphroditism in this species. Behaviorally, C. mesoleucus appears quite similar to a large group of species proposed herein to represent a generalized pomacanthid behavioral type. Divergences from this generalized type by members of Genicanthus, eastern Pacific Holacanthus, and western Atlantic Pomacanthus are discussed. Evidence is given to suggest the phylogenetic derivation of the subgenus Centropyge (genus Centropyge) from an ancestor of the subgenus Xiphipops type. Color dimorphism and “rendezvous sites” are briefly discussed.