Nitrogen isotope composition of amino acids reveals trophic partitioning in two sympatric amphipods.

ABSTRACT: According to ecological theory, two species cannot occupy the same niche. Using nitrogen isotope analyses (δ¹⁵N) of amino acids, we tested the extent to which two sympatric deposit-feeding amphipods, Monoporeia affinis and Pontoporeia femorata, partition their trophic resources. We found that trophic position (TP) and resynthesis index (∑V; a proxy for degradation status of ingested material prior to assimilation by the consumer) differ between species. The surface-feeding M. affinis had higher TP and intermediate ∑V, both pointing to a large contribution of metazoans in its diet. P. femorata, which feeds in the subsurface layers, had lower TP and a bimodal distribution of the ∑V values, supporting previous experimental evidence of a larger feeding ni

SUBMITTER: Ledesma M 

PROVIDER: S-EPMC7548185 | biostudies-literature | 2020 Oct

REPOSITORIES: biostudies-literature