Function of the shell spine in the predaceous rocky intertidal snail Acanthina spirata (Prosobranchia: Muricacea)

PREDATOR-INDUCED SHELL DIMORPHISM IN THE ACORN BARNACLECHTHAMALUS ANISOPOMA

“…The bent morphology, therefore, acts to functionally remove the spine. This result is consistent with the findings of Perry (1983) who showed that A. spirata with their spines experimentally removed consumed fewer barnacles per unit time than did control snails. In her study, spineless snails attacked the barnacles by drilling with their radulae.…”

“…The results also show that bents are more resistant than conics to specialized predation by A. angelica. Members of the genus Acanthina have a spine on the outer lip of the aperture which is used to attack barnacle prey (Sleder, 1981;Yensen, 1979;Perry, 1983). The attack sequence involves orientation of the spine directly above the barnacle, followed by a downward thrust in an attempt to penetrate the barnacle's opercular valves.…”

Molecular Phylogenetics and The Evolution of Labral Spines among Eastern Pacific Ocenebrine Gastropods

“…Labral spines function to break or force apart the opercular plates of prey barnacles (Paine, 1966;Sleder, 1981;Malusa, 1985;Perry, 1985), to wedge apart or to edge-drill the valves of pelecypod molluscs (Vermeij, 1978(Vermeij, , 1987Kent, 1981), or to pry open the operculae of prey gastropods. Spine-bearing snails can penetrate the hard exoskeletons of their prey in only a fraction of the time required by spine-lacking snails: handling time is reduced by at least one-half in species of Acanthinucella (Perry, 1985) and by perhaps as much as 90% among species with larger spines (Pearson and Marko, pers. comm.).…”

Influence of alternative shell‐drilling behaviours on attack duration of the predatory snail, Chicoreus dilectus

“…By shortening the duration of the predation process, edge drilling falls into the same category as other important evolutionary innovations and presumably derived behaviours of attacking at the edge of prey in the Muricidae that have improved upon or in some instances completely replaced the slower method of wall drilling (Vermeij & Carlson, 2000;Herbert, 2004). These other alternatives to wall drilling include the use of venomous toxins (Roseghini et al, 1996;Rovero et al, 1999;Urrutia & Navarro, 2001), grinding or wedging using the shell outer lip (Wells, 1958), and prying or ramming using a labral spine (Perry, 1985;Vermeij, 2001). For instance, the 'edge' attack behaviour of Nucella lapillus to inject toxins into the shell of the blue mussel Mytilus edulis was 53% faster than drilling through the mussel's shell wall (Rovero et al, 1999).…”

“…For instance, the 'edge' attack behaviour of Nucella lapillus to inject toxins into the shell of the blue mussel Mytilus edulis was 53% faster than drilling through the mussel's shell wall (Rovero et al, 1999). Spine-prying behaviour of Acanthina spirata at the edge of its barnacle prey was also about two to five times faster (depending on prey species) than wall-drilling behaviour (Perry, 1985).…”