Attack responses of the southern Australian whelk, Lepsiella vinosa (Lamarck, 1822) (Gastropoda: Muricidae), to novel bivalve prey: an experimental approach

In their native ranges, muricid gastropods feed on similar prey, often bivalves and barnacles, which they usually drill. Throughout its wide southern Australian distribution, the intertidal Lepsiella vinosa feeds on a range of prey from barnacles and littorinid gastropods in the southeast to mussels in the southwest. A number of muricids have been introduced throughout the world, either with oysters or in ship ballast water. In their new environments, they switch to native prey but their feeding responses to them have never been studied in the laboratory. The object of this study was to study the feeding of L. vinosa on a suite of non-native species. Australian Lepsiella vinosa was taken to Hong Kong, offered five different possible prey species and allowed to feed to satiation for many weeks. Replacement of consumed prey items by similar-sized conspecifics was undertaken until trends emerged. Lepsiella vinosa readily attacked thick- and thin-shelled bivalves from Hong Kong's sandy beaches, Anomalocardia squamosa and Caecella chinensis, respectively, and from rocky shores, Septifer virgatus and Hormomya mutabilis, again respectively. It attacked them all, as it does its major prey item, Xenostrobus inconstans, in its native southwestern Australia, by either drilling or marginal probing with its proboscis. It also preferred intermediate sized prey (10-15 mm shell length), as with its natural prey. It quickly attacked the sandy shore species, and Hormomya mutabilis and Mytilopsis sallei, the latter two being closely similar in shell form and size to its natural prey X. inconstans. Hormomya mutabilis was the most favored prey, and was most similar in shell form and thickness to X. inconstans. This study therefore suggests that if introduced elsewhere, L. vinosa could radically affect intertidal community structure.