Abstract.Food preferences of six dominant salt marsh invertebrates were studied to identify detritivores and to assess differences in their diets. Animals fed on agar suspensions of dead and live foods in petri dishes with four compartments. Only two foods were included in each dish. Relative palatability was assessed by measuring the amount of suspension removed or by counting the number of feeding marks left on the surface of the suspensions.Feeding marks reflected differences in mouth parts and feeding mechanisms of the six invertebrates.Melampus bidentatus, Orchestia grillus, andPhiloscia vittatapreferred dead litter over live tissues of marsh graminoids, blue‐green algae, and sulfur bacteria. No preference for detritus from different graminoids was shown byM. bidentatus. Orchestia grillusfed preferentially onSpartina patensdetritus.Philoscia vittatapreferred detritus fromS. alternifloraandS. patens.Blue‐green algae and sulfur bacteria were preferred over detritus byLittorina saxatalis, but detritus was preferred over live graminoids.Littorina saxatalisfed preferentially onJuncus gerardidetritus. Blue‐green algae, sulfur bacteria, and live graminoids were preferred over detritus byL. littorea. Talorchestia longicornisalso preferred blue‐green algae.On the basis of their food preferences,Littorina saxatalis, Melampus bidentatus, Orchestia grillus, andPhiloscia vittatawere classified as detritivores. Feeding on detritus from different plant species could result in a partitioning of this food resource in the detritus‐based food chains of the salt marsh
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