Cirral activity and feeding in the coral-inhabiting barnacleBoscia anglicum(Cirripedia)

Abstract

In spite of a specialized shell structure and an obligate coral-inhabiting mode of life,B. anglicumretains a generalized balanoid operculum, cirri and mouthparts. These are used to capture and ingest live planktonic prey such as nauplii. Prolonged cirral extension is a preliminary to prey capture but the capture process itself involves the beating down of the prey by a series of up to six contractions and extensions of the cirri in 7–10 s. The prey is then grasped by the extended third maxillipeds (cirrus III) and drawn into the mantle cavity. An antenniform exopod of cirrus I is extended and detects the prey at the beginning of the capture sequence. The exopods of cirrus I are also used in the rejection of any unwanted particles grasped and taken in by the third maxillipeds.