[en] Vagile invertebrates are regarded as key-components of Posidonia oceanica meadow ecosystems, particularly in organic matter transfers from primary producers to higher level consumers. Among these invertebrates, amphipod crustaceans are one of the most abundant and diverse groups, and probably play an important role in meadow ecosystem functioning. However, their trophic ecology is poorly known, and these crustaceans are generally regarded as vegetal epiphytes consumers or generalist detritivores, due to the lack of accurate studies.
Here, we focused on the study of the interspecific trophic diversity, and on the importance of other food sources (Posidonia leaves and litter, animal epiphytes, suspended particular organic matter, …) in those amphipods’ diet. To assess these phenomena, we used stable isotopes ratios of carbon and nitrogen as trophic tracers.
It appears that, while some species (such as Apherusa chiereghinii and Aora spinicornis) seem to feed mainly on epiphytes, others, like Dexamine spiniventris, exploit different food sources. These results thus tend to show that amphipod trophic diversity could have been underestimated in the past. Moreover, they enhance the comprehension of the feeding ecology of these animals, and therefore of the way they interact with the Posidonia meadow ecosystem.
