A laboratory study of predation by the dog-whelk <i>Nucella lapillus</i> on the barnacles <i>Elminius modestus</i> and <i>Balanus balanoides</i>

Abstract

Predation of the barnacles Balanus balanoides and Elminius modestus by the common dog-whelk, Nucella lapillus was studied in the laboratory. Greater numbers of B. balanoides were taken as prey unless the whelks had been previously subjected to an extensive period of starvation. Selective predation is discussed in the light of similar studies on Nucella and related predatory species. The effects of prey selection on the competitive interactions of the prey species are also considered. The method of predatory attack involves either a drilling or a prizing technique. The latter is used predominantly when Nucella attacks E. modestus , whereas drilling is employed to a far greater extent when attacking B. balanoides . Attacks using the drilling technique are usually made at the occludent margins of the opercular valves.