Effects of predator density on the predation efficiency of the dogwhelk (Reishia clavigera)

Species interactions have long been recognized as essential in the organization of communities, and the density of predators is critical in the interaction between predator and prey. Our study explores how predator density affects predation efficiency in a typical intertidal predator (dogwhelk Reishia clavigera) - prey (mussel Mytilus galloprovincialis) system. Three treatments with different predator densities were established: low-density treatment (LD, one dogwhelk/dm²), medium-density treatment (MD, four dogwhelks/dm²), and high-density treatment (HD, eight dogwhelks/dm²). The number frequency of dogwhelks on the mussel, prey searching and handling time, feeding success rate, and shell thickness of mussels were calculated. The results showed that the presence of a higher density of predators facilitated more successful predation. The higher the density of dogwhelk, the less time dogwhelks spend on predation. The predation methods of dogwhelks, either drilling holes or prying open, did not rely on predators' density, but the dogwhelks preferred to drill holes at the thin edge of the mussel shells. This study highlights the impacts of predator density on predation efficiency in the intertidal community.