Stable isotopes unravel the feeding mode-trophic position relationship in trematode parasites

It was possible to ‘rank’ these parasite species and assess their ‘relative’ trophic position using δ15N values. We also demonstrated that including a broader range of samples (e.g. host food and faeces, multiple parasite life stages) helped understand the metabolic mechanisms used by the various participants, and that using carbon stable isotope values and C:N ratios allowed to identify an important lipid requirement of these trematode parasites.

Finally, we show how critical it is to not ignore parasitic infections as they can have a great influence on their host’s trophic position. 5. We have shown that by focussing on a single host species and a single taxonomic group of parasites, we can remove a certain amount of variation recorded by broader isotope studies. We hope that these data will ultimately improve our ability to place parasites in food webs, and thus improve our understanding of the connections and interactions that dictate food web dynamics.