Available online 28 March 2022

A specific metabarcoding approach was applied to a fish-monogenean host-parasite system.

Species diversity of Lamellodiscus monogeneans was assessed on fish skin and gills.

Metabarcoding provided a better assessment of parasitic diversity than with morphological identification.

High diversity of parasites was found, including Lamellodiscus from new hosts.

Our results suggest multiple levels of regulation of host specificity in monogeneans.

Monogeneans are highly diverse fish ectoparasites with a direct life cycle, widely distributed and are known to generally display strict host specificity. Factors related to the hosts and the parasite have been suggested to explain this high specificity. Monogeneans have also been observed to colonize fish species not in their natural host range under experimental conditions. We developed a specific metabarcoding protocol and applied it on the Sparidae-Lamellodiscus host-parasite system, to assess parasite diversity on skin and gills of several sparid host species. We first demonstrated that the use of a metabarcoding approach provided a better understanding of the diversity of monogeneans associated with teleost skin and gills than traditional approaches based on morphological identification. We identified a high diversity of both expected and unexpected (never observed on this host species) Lamellodiscus spp. on each host species and on skin and gills. No significant difference in parasite diversity was found between skin and gills. These results suggest that the establishment of the observed host specificity in monogeneans relies on multiple levels of regulation, involving the survival capacity of the larvae and host recognition mechanisms.

Monogenean

Teleost

Specificity

Metabarcoding approach

Diversity

Host-parasite interactions

© 2022 Australian Society for Parasitology. Published by Elsevier Ltd. All rights reserved.