Trophic ecology of Hyalella sp. (Crustacea: Amphipoda) in a High Andes headwater river with travertine deposits

Abstract

We studied the diet of 50 individuals of Hyalella sp. collected in the karstic headwaters of a highaltitude Andean river (3817 m a.s.l. Peru) in four different habitats: macrophytes, bryophytes, leaf litter, and layers of travertine. The gut content analysis showed a dominance of fine particulate organic matter (FPOM) in most habitats - layers of travertine (69.5%), Myriophylum (58.5%) and bryophytes (56.8%) - except for individuals collected in leaf litter where coarse particulate organic matter (CPOM) represented 68% of gut content, which indicates a high trophic flexibility of Hyalella sp. Likewise, in an experiment with feeding chambers in situ during three days, twenty individuals of Hyalella sp. presented a higher consumption of leaf litter of native species (Polylepis sp.) (0.025 mg/day) than those of an introduced species (Eucalyptus globulus) (0.008 mg/day).