Dieta do cascudo Aspidoras fuscoguttatus (Ostariophysi, Callichthyidae) em riachos com diferentes características limnológicas e estruturais / Diet of the armored catfish Aspidoras fuscoguttatus (Ostariophysi, Callichthyidae) in streams with different limnological and structural features

ABSTRACT

In the present study Aspidoras fuscoguttatus Nijssen & Isbrücker, 1976 diet was investigated based on specimens from 18 streams of São Paulo State northwestern region, upper Rio Paraná system. Stomach contents of 246 specimens were analyzed, with the registration of 26 types of feeding items showing high predominance of the autochthonous ones. Of these, Chironomidae, Simuliidae, and Ceratopogonidae aquatic larvae were the most important items, but the contribution of detritus, testate amoebas, and vegetal debris changed according to streams features. Whereas in clear waters feeding items can be visually selected by fishes, in turbid waters this selection may not occur. Thus, the species' ability in taking resources in sandy streams with turbid waters and the abundance of resources (Chironomidae larvae) are factors that seem to explain its high abundance and broad occurrence in the region.