Réponses comportementales des polychètes Nereis diversicolor (O.F. Müller) et Nereis virens (Sars) aux stimuli d'ordre alimentaire : utilisation de la matière organique particulaire (algues et halophytes)

Plant preference and feeding selectivity were studied in juveniles of Nereis diversicolor O.F. Muller) and Nereis virens (Sars) (Polychaeta: Nereidae) to evaluate the potential role of these species in the integration and transfer of vegetal debris to the littoral ecosystem. Results show that these annelids ingest the main plant species (algae and halophytes) that are abundant in the marshes of the bay of Mont-Saint-Michel (France) and (or) the A l'Orignal Inlet (St. Lawrence Estuary, Canada), independently of their origin or level of decomposition. Juveniles select detritus on the sediment surface (feeding area) and accumulate them in their burrow. Constant irrigation by young individuals (≈35% of time budget) maintains aerobic conditions favouring the decay process of plant debris by stimulating bacterial growth (gardening). Our results suggest that individuals of both N. diversicolor and N. virens play an important role in the transfer and integration processes and the residence time of vegetal detritu...