Feeding ecology of Limnoperna fortunei in southern China: insights from stable isotopes and fatty-acid biomarkers

Abstract

ABSTRACTLimnoperna fortunei (L. fortunei) is one of the most abundant freshwater bivalves in southeast Asia, with wide-ranging direct and indirect impacts on ecosystems. To estimate material flows in the habitats of L. fortunei, a combination of stable-isotope and fatty-acid analyses were applied to assess the feeding spectrum of L. fortunei in southern China. Using the isotope-mixing model, the contribution proportions to the diet of L. fortunei were estimated as 19.8%–28.2% for plankton, 57.6%–65.2% for particulate organic matter (POM) and 10.2%–21.1% for sediment organic matter. We conclude that POM is the principal food source of L. fortunei. The δ13C enrichment of fixed carbon from POM to L. fortunei was 0.67%–2.41%. Based on the fatty acid data, it was estimated that L. fortunei consumed or selectively accumulated Chlorophyceae, Cryptophyceae, Dinophyceae, bacteria and terrestrial organic matter. The feeding spectrum of L. fortunei is similar to that of Dreissena polymorpha. We suggest that L. fortunei is able to differentiate suitable food items using chemical cues and the surface properties of particles.