Corallivory and prey choice by Drupella rugosa (Gastropoda: Muricidae) in Hong Kong

Prey choice experiments demonstrated preference by the muricid gastropod Drupella rugosa for Acropora pruinosa and Montipora informis, whereas four other species, i.e. Leptastrea purpurea, Pavona decussata, Platygyra sinensis and Favia speciosa, were avoided. Drupella rugosa responded to A. pruinosa more readily than to M. informis. Drupella rugosa also spent significantly different times locating and feeding upon A. pruinosa and M. informis, but was generally slow to be attracted to and locomote towards corals, probably because of its intimate association with them as an obligate predator. A second experiment indicated that significantly more D. rugosa were attracted to corals stressed mechanically and with low salinity water than to unstressed ones. The feeding activity of an individual D. rugosa also stimulated conspecifics to feed. Feeding aggregations were thus formed at individual coral pieces, as observed in the field, and accounting for previously reported `outbreaks' of the predator in Hong Kong.