Isotopic discrimination in helminths infecting coral reef fishes depends on parasite group, habitat within host, and host stable isotope value.

ABSTRACT: Stable isotopes of carbon and nitrogen characterize trophic relationships in predator-prey relationships, with clear differences between consumer and diet (discrimination factor ?¹³C and ?¹⁵N). However, parasite-host isotopic relationships remain unclear, with ?¹³C and ?¹⁵N remaining incompletely characterized, especially for helminths. In this study, we used stable isotopes to determine discrimination factors for 13 parasite-host pairings of helminths in coral reef fish. Differences in ?¹⁵N values grouped according to parasite groups and habitat within the host with positive ?¹⁵N values observed for trematodes and nematodes from the digestive tract and variable ?¹⁵N values observed for cestodes and nematodes from the general cavity. Furthermore, ?¹³C values showed more complex patterns with no effect of parasite group or habitat within host. A negative relationship was observed between ?¹⁵N and host ?¹⁵N values among different host-parasite pairings as well as within 7 out of the 13 pairings, indicating that host metabolic processing affects host-parasite discrimination values. In contrast, no relationships were observed for ?¹³C values. Our results indicate that parasite group, habitat within host, and host stable isotope value drive ?¹⁵N of helminths in coral reef fish while their effect on ?¹³C is more idiosyncratic. These results call for use of taxon- or species-specific and scaled framework for bulk stable isotopes in the trophic ecology of parasites.

SUBMITTER: Riekenberg PM 

PROVIDER: S-EPMC7907083 | biostudies-literature | 2021 Feb

REPOSITORIES: biostudies-literature