Analysis of the use of microhabitats, spatial distribution and diet of Gymnorhamphichthys rondoni (Miranda-Ribeiro, 1920) (Rhamphichthyidae) in low-order streams in western Amazon

Abstract

The feeding habit, psammophilous behavior and the morphology of Gymnorhamphichthys rondoni make it a highly specialized species with an important role in stream ecosystems. Accordingly, the aim of the present study was to analyze the use of microhabitats, diet composition, feeding strategies, niche breadth and spatial distribution of G. rondoni species in headwater streams. In each of the three selected streams (P1, P2 and P3), located on the Catuaba Experimental Farm (Acre, Brazil), we collected three samples of organic matter substrate and three of clay during drought, ebb and flood periods. The results showed that the population of G. rondoni increased along the longitudinal gradient, mainly during drought (376 individuals), in which the individuals occupied substrates composed of sand and showed a diet based mainly on benthic prey such as larvae of Diptera and Coleoptera. Thus, the preference for feeding on autochthonous larvae by G. rondoni and their specialized morphology may be due to their relationship with sand microhabitats. Thus, the loss of these microhabitats may negatively influence the population of G. rondoni.

Keywords

• Alimentação
• Ambientes lóticos
• Amplitude de nicho
• Especialização
• Psamofilia