Abstract
The behavior of marine larvae during and after settlement can help shape the distribution and abundance of benthic juveniles and therefore the intensity of ecological interactions on reefs. Several laboratory choice-chamber experiments were conducted to explore sensory capabilities and behavioral responses to ecological stimuli to better understand habitat selection by “pre-metamorphic” (larval) and “post-metamorphic” (juvenile) stages of a coral reef Wsh (Thalassoma hardwicke). T. hardwicke larvae were attracted to benthic macroalgae (Turbinaria ornata and Sargassum mangarevasae), while slightly older post-metamorphosed juveniles chose to occupy live coral colonies (Pocillopora damicornis). Habitat choices of larvae were primarily based upon visual cues and were not inXuenced by the presence of older conspeciWcs. In contrast, juveniles selected live coral colonies and preferred those occupied by older conspeciWcs; choices made by juveniles were based upon both visual and olfactory cues from conspeciWcs. Overall, the laboratory experiments suggest that early lifehistory stages of T. hardwicke use a range of sensory modalities that vary through ontogeny, to eVectively detect and possibly discriminate among diVerent microhabitats for settlement and later occupation. Habitat selection, based upon cues provided by environmental features and/or by conspeciWcs, might have important consequences for subsequent competitive interactions