부산대학교 도서관

The composition of the diet of two species of characids (Knodus heteresthes and Moenkhausia lepidura) was evaluated in the Teles Pires and Juruena Rivers, sampled in September and October 2016. We analyzed 226 stomachs of K. heteresthes and 425 of M. lepidura. The analysis of the stomach contents was based on volumetric and frequency of occurrence methods, applying the food importance index. For the similarity of the diets between the species we calculated the niche overlap with Pianka's index. Both species in the Juruena River have a dietary preference for arthropods (IAi > 0.95). In the Teles Pires River the diet is concentrated in three sources for both species: arthropods (IAi > 0.52), vegetables (IAi > 0.33) and fish (IAi > 0.12). The diet was dissimilar when compared to environments (ANOSIM, R [greater than or equal to] 0.57, p < 0.001) with high trophic niche overlap ([alpha] > 0.97), regardless of the sampled environment. In the Teles Pires River, both species were classified as omnivorous with an insectivorous tendency and in the Juruena River the insectivorous behaviour occurs. Keywords: diet, trophic niche, insectivory. Foram avaliadas a composicao da dieta de duas especies de Characideos (Knodus heteresthes e Moenkhausia lepidura) nos rios Teles Pires e Juruena, amostrados em setembro e outubro de 2016. Analisamos 226 estomagos de K. heteresthes e 425 de M. lepidura, sendo utilizados os metodos volumetrico e frequencia de ocorrencia, aplicando-se o indice de importancia alimentar. Para a similaridade das dietas entre as especies calculamos a sobreposicao de nicho com indice de Pianka. Ambas as especies no rio Juruena tem preferencia alimentar por artropodes (IAi > 0,95), no rio Teles Pires a dieta concentra-se em tres fontes para ambas especies: artropodes (IAi > 0,52), vegetais (IAi > 0,33) e peixes (IAi > 0,12). A dieta e dissimilar quando comparados os ambientes (ANOSIM, R [greater than or equal to] 0,57; p < 0,001), com alta sobreposicao de nicho trofico ([alpha] > 0,97), independente do ambiente amostrado. No rio Teles Pires, ambas as especies foram classificadas como onivoras com tendencia insetivora e no rio Juruena ocorre o comportamento insetivoro. Palavras-chave: dieta, nicho trofico, insetivoria.
1. Introduction Neotropical freshwater fish represent one-eighth of all vertebrate biodiversity and approximately one-fourth of that of the globe fish species (Vari and Malabarba, 1998), and among them, the Family [...]