Does invasive Chondrostoma nasus shift the parasite community structure of endemic Parachondrostoma toxostoma in sympatric zones?

Abstract

BackgroundThe composition of parasite communities in two cyprinid species in southern France – native and threatened Parachondrostoma toxostoma and introduced Chondrostoma nasus – was investigated. In sympatry, these two species form two hybrid zones in the Durance and Ardeche Rivers. Due to their different feeding preference and habitat positions in allopatry, we supposed a difference in parasite communities between fish species. We expected more similar parasite communities in sympatric zones associated with habitat overlap (facilitating the transmission of ectoparasites) and similar feeding (more generalist behaviour when compared to allopatry, facilitating the transmission of endoparasites) in both fish species. Finally, we investigated whether P. toxostoma x C. nasus hybrids are less parasitized then parental species.MethodsOne allopatric population of each fish species plus two sympatric zones were sampled. Fish were identified using cytochrome b gene and 41 microsatellites loci and examined for all metazoan parasites.ResultsA high Monogenea abundance was found in both allopatric and sympatric populations of C. nasus. Trematoda was the dominant group in parasite communities of P. toxostoma from the allopatric population. In contrast, the populations of P. toxostoma in sympatric zones were parasitized by Dactylogyrus species found in C. nasus populations, but their abundance in endemic species was low. Consequently, the similarity based on parasite presence/absence between the sympatric populations of P. toxostoma and C. nasus was high. Sympatric populations of P. toxostoma were more similar than allopatric and sympatric populations of this species. No difference in ectoparasite infection was found between P. toxostoma and hybrids, whilst C. nasus was more parasitized by Monogenea.ConclusionsThe differences in endoparasites between P. toxostoma and C. nasus in allopatry are probably linked to different feeding or habitat conditions, but host-parasite evolutionary associations also play an important role in determining the presence of Chondrostoma-specific monogeneans. Our findings suggest that Dactylogyrus expanded with the source host C. nasus into introduced areas and that P. toxostoma became infected after contact with C. nasus. Although the genotype of P. toxostoma and recombinant genotypes of hybrids are susceptible to Dactylogyrus transmitted from C. nasus, the intensity of infection is low in these genotypes.

Does interspecies hybridization affect the host specificity of parasites in cyprinid fish?

“…A similar finding, i.e. low infection by metazoan parasites (especially Monogenea), was found for hybrids of P. toxostoma and C. nasus from the Durance and Ardeche (South France) sympatric zones [10]. However, in their study, both the P. toxostoma genotype and the recombinant genotypes of hybrids were less susceptible to Dactylogyrus parasites when compared to the pure C. nasus genotype, suggesting co-evolutionary interactions between C. nasus and their Dactylogyrus species.…”

“…Concerning cyprinid fish, it is estimated that more than 30% are hybrids [8]. Currently, there is a lack of knowledge concerning host susceptibility to metazoan parasites in fish hybrids, and only two studies dealing with the host specificity of some metazoan parasites in hybridizing cyprinid fish have been performed [9,10]. …”

“…The highly frequent natural hybrids of two cyprinid species, Alburnus alburnus and Rutilus rubilio , from Lake Mikri Prespa (Northern Greece) showed a high susceptibility to metazoan parasites when compared with pure species [9]. However, the hybrids of two cyprinids, native Parachondrostoma toxostoma and invasive Chondrostoma nasus in southern France, were less parasitized by ecto- and endoparasites than both pure species in the localities where these fish species live in sympatry [10]. …”

Metazoan parasite communities: support for the biological invasion of Barbus barbus and its hybridization with the endemic Barbus meridionalis

“…This may be supported by higher similarity in parasite communities between the Argens recent sympatric BB and the Argens recent sympatric BM than between the Argens recent sympatric BB and the Argens allopatric BM. In general, similar parasite communities are expected in hosts living in sympatric areas as a result of host contact, which facilitates parasite transmission [72]. Our findings, therefore, highlight the risk of possible parasite transmission from invasive BB to endemic BM.…”

“…Our findings, therefore, highlight the risk of possible parasite transmission from invasive BB to endemic BM. Šimková et al [72] indicated that local and endemic Parachondrostoma toxostoma became infected by Dactylogyrus parasites after contact with the invasive Chondrostoma nasus in southern France. In our study, Dactylogyrus parasites were very rare in BM.…”