Temporal effects on host-parasite associations in four naturalized goby species living in sympatry

Abstract

Introduced host species are often characterised by reduced parasite numbers compared to their native populations. Any such advantage gained from parasite release following introduction into a new area may often diminish over a short period as the new host gradually acquires local parasites. In this study, the metazoan parasite communities of four goby species (Proterorhinus semilunaris, Ponticola kessleri, Neogobius melanostomus, and Neogobius fluviatilis) recently introduced into the lower River Rhine were investigated. Mean parasite abundance and infracommunity richness were positively associated with time since host introduction, both parasite variables being the highest in P. semilunaris. In Ponticola and Neogobius species, parasite species richness and the dominance of larval parasites in the Lower Rhine were similar to that for non-native populations in the middle Danube. Sporadic local parasite acquisition and infection, predominantly by species commonly found in the native range, led to a relatively high qualitative similarity in parasite communities between hosts. The relationship between parasite abundance and fish size reflected size-dependant food selectivity and/or parasite accumulation throughout the host’s life. Data from this study emphasise the importance of duration of co-occurrence, host habitat and foraging preference, as well as the co-introduction of suitable intermediate hosts, for parasite community composition in related species.