Over the past few years, we have been working on a symbiosis that exists between a coral host and its crustacean inhabitants. Pocillopora is a common and geographically widespread genera of branching coral that houses an extraordinary diversity of crustaceans and fishes. Many of these coral constituents partake in a symbiosis with the coral whereby the coral host provides shelter and food in exchange for protective services by the symbiont (similar to well-known ant-plant mutualisms where ants protect plants from herbivores in exchange for nectar and domatia). Previous work on this symbiosis has emphasized the benefits provided to the coral by crab inhabitants (genusTrapezia) in deterring predators and removing sediment from the coral’s surface. Our research attempts to deepen our understanding of the system in three ways. (1) We seeks to understand and describe new ways in which crustacean mutualists benefit the coral. (2) We study how synergism and antagonism among different symbiont species affect the strength and stability of the mutualism. (3) We address the role of predation as a force affecting the abundance, diversity, and composition of the crustacean guild.
We recently published a paper in Coral Reefs describing a new component of this mutualism, whereby coral crustaceans ameliorate the negative effects of mucus-feeding snails (Dendropoma maximum). Two companion papers are near publication (one in press at Oecologia and one in press at PLoS One) that examine how ecological services (sediment removal and deterrence of predatory seastars) provided by two coral crustaceans (a crab: Trapezia serenei and a shrimp: Alpheus lottini) shift with crustacean density, identity, and diversity. We currently also have one paper in review at Ecology that explores how two different predatory fishes that also live inside the coral (Flame Hawkfish and Coral Crouchers) affect the abundance and diversity of the crustacean guild.
This system is exciting and offers extraordinary opportunity to understand more about the dynamics of a poorly studied, yet extraordinarily diverse guild of reef invertebrates, a group that makes up the vast majority of reef biodiversity.
This work has benefited immensely from contributions by a suite of collaborators: Shelby Boyer, Mike Gil, Sarah Lemer, Matthieu Leray Sea Mckeon, Suzie Mills, Craig Osenberg, Adrian Stier, and Jeff Shima. (listed alphabetically)