INTEGRATING EXPERIMENTS WITH SUBTIDAL DEATH ASSEMBLAGES TO UNVEIL THE PREDATORY HABITS OF MURICID GASTROPODS FROM THE SOUTHEASTERN PACIFIC

Abstract: As quantitative tools, drill holes have been used to calculate predation frequencies in time and space. These traces can also inform predator preference and some strategies predators use to drill on prey (e.g., edge drilling, site stereotypy, or alternative modes of predation when there is no drill hole). In this study, our goal was to leverage the informative power of drill holes to characterize the predatory habits of muricid gastropods from the central coast of Chile. We integrated information from experiments and death assemblages (DAs) to unveil the predatory strategy of Ancathina monodon, Crassilabrum crasilabrum, and Concholepas concholepas on the mobile gastropod Tegula tridentata and the sessile bivalve Perumytilus purpuratus. Experiments supported previous findings for predatory strategies (basal spine for Ancathina and alternative modes of predation for Concholepas), and showed the stereotypic predation of Crassilabrum on Tegula—a herbivore that is devastating subtidal kelp forests. Based on drill holes from DAs, at least 11 molluscan families are consumed by muricids in these communities. DAs also helped validate the stereotypic predation of Crassilabrum on Tegula, as drill holes were found in the same position both in experiments and DAs. Despite their thinner shells, mytilids were well represented in DAs and were found with drill holes in the five locations sampled. We describe for the first time the predatory strategy of Crassilabrum in Chile and confirm that muricids other than Concholepas are active predators on subtidal rocky habitats from the southeastern Pacific Ocean, a region that is still understudied.