Emerging associations on marine rocky shores: specialist herbivores on introduced macroalgae

摘要: Summary 1 Sacoglossan sea slugs (Gastropoda: Opisthobranchia) can change their highly specialized algal host associations in response to introduced hosts. 2 Adult sacoglossans (Placida dendritica) collected from the green macroalga Codium fragile ssp. tomentosoides west-coast Scottish lochs tended associate with and consume hosts over native C. tomentosum pairwise-choice feeding trials. 3 On Irish shores, where congeneric were more common, significantly P. dendritica attacked on shore whereas Elysia viridis disproportionately exotics. In Lough Hyne, Co. Cork, Ireland, juvenile E. both native, sympatric vermilara; trials, preferred species which they collected. 4 In Channel Islands, adult common Guernsey shores. trials adults exhibited no preference between hosts, indicating that stenophagous herbivores could associations. 5 On temperate Australian sacoglossan Placida aoteana recently as well congeners conspecifics. was its herbivory evident Victoria Tasmania. Slugs subspecies but a strong for Tasmania. 6 Flexibility use enables marine respond within years presence of hosts. The implicit peril host-specificity paradigm − that specialists associations − does occur sacoglossans, there is considerable intra- interspecific variation response. 7 Biological control invasive algae using fraught several risks, including taxonomic uncertainty species’ boundaries, ecological flexibility feeding, unexplored role susceptibility insufficient evolutionary–developmental information establish coevolutionary associations.