DAO 84:65-77 (2009)  -  DOI: https://doi.org/10.3354/dao02022

Digenean trematodes–marine mollusc relationships: a stable isotope study

S. Y. Dubois1,*, N. Savoye1, P.-G. Sauriau2, I. Billy3, P. Martinez3, X. de Montaudouin1

1Université de Bordeaux, CNRS UMR 5805, EPOC, Station Marine d’Arcachon, 2 rue du Pr. Jolyet, 33120 Arcachon, France
2Université de La Rochelle, CNRS UMR 6250, LIENSs, 2 rue Olympe de Gouges, 17000 La Rochelle, France
3Université de Bordeaux, CNRS UMR 5805, EPOC, Avenue des Facultés, 33405 Talence cedex, France

ABSTRACT: The stable carbon and nitrogen isotopic composition of digenean trematode parasites and their marine mollusc hosts was investigated to describe the potential influence of parasites on their host and its different tissues, and to obtain further insight into their trophic relationships. Four parasite–host systems were studied: Labratrema minimusCerastoderma edule, Monorchis parvusC. edule, Lepocreadiidae parasites–Nassarius reticulatus and Zoogonidae parasites–N. reticulatus. Among the 4 sampling occasions reported here and corresponding to the 4 parasite–host systems, isotopic shifts from pathologic (i.e. linked to disturbances in host metabolism) and mass-balance (i.e. linked to significant differences between host and parasite isotopic signatures) origins were observed only once. Both corresponded to δ13C measurements of the L. minimusC. edule system when the infestation load (percentage parasite dry weight compared to total flesh dry weight) was highest (9 to 25%, mean = 16%) over the sampling period. Overall, measurements indicate that digenean trematode parasitism induced low or no shifts in isotopic signatures of C. edule and N. reticulatus tissues. The 2 endoparasites L. minimus and M. parvus appeared to be slightly depleted in 13C compared to C. edule digestive gland and gonads, which were the most parasitized tissues. In contrast, no fractionation or low 15N trophic enrichments occurred in the parasites. These results highly contrast with the classical trophic enrichment reported in prey–predator systems but are in agreement with the scarce literature regarding other parasite–host systems. Our results indicate that (1) digenean trematodes mainly feed on digestive glands (the cockle tissue with which they are mainly associated) with a possible slight preference for lipids, and (2) fractionation due to parasite metabolism should be low due to abbreviated metabolic pathways and/or slight loss of materials through excretion, tegument diffusion and respiration.

KEY WORDS: Parasitism · C and N stable isotopes · Marine molluscs · Digenean trematodes

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Cite this article as: Dubois SY, Savoye N, Sauriau PG, Billy I, Martinez P, de Montaudouin X (2009) Digenean trematodes–marine mollusc relationships: a stable isotope study. Dis Aquat Org 84:65-77. https://doi.org/10.3354/dao02022

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