Abstract
The stomach contents of 172 individuals of Hypostomus plecostomus and 94 specimens of Hypostomus emarginatus from the Coaracy Nunes reservoir in northern Brazil were analyzed in order to evaluate the feeding ecology of the two fish species from this site. Data were collected in eight campaigns conducted every two months between May, 2010 and July, 2011, four in the dry season and four during the flood period. The analysis of the stomach contents was based on the volumetric frequency (VF%) and frequency of occurrence (FO%), combined with the feeding index (FI). Nine different dietary items were identified: detritus, plant fragments, zooplankton, arthropods, chlorophytes, bacillariophytes, cyanobacteria, dinophytes, and unidentified material. Detritus was the principal component of the diet during both seasons, with all the other items representing only complementary or accidental portions of the diets of both species. Niche breadth was low overall, but slightly greater in H. plecostomus in comparison with H. emarginatus . Niche overlap was accentuated in both seasons, which indicates that seasonality is not a major factor influencing the characteristics of the niches of these species, possibly because of the marked abundance of detritus in the study area, specifically in the impounded sector. The two species can be characterized as detritivores, which share dietary resources with no clear evidence of any negative effects of interspecific competition on the coexistence of the two populations. Keywords: Feeding ecology; niche breadth; Araguari River; Amazonia.
Highlights
Ecological theory predicts that each species of animal occupies a unique niche which characterizes its relationship with the dietary resources available in the environment (BRADLEY; BRADLEY 1985)
Diet breadth and niche overlap between Hypostomus plecostomus (Linnaeus, 1758) and Hypostomus emarginatus dynamics of fish species represent an important approach to the understanding of other aspects of the biology of these animals, such as their reproduction, ontogeny, demographic patterns, migration and niche partitioning (HANN et al, 1996)
A total of 172 specimens of H. plecostomus were collected during the study period (63 during the flood period, and 109 at low water), and 94 of H. emarginatus (39 in the flood, and 51 in the dry season)
Summary
Ecological theory predicts that each species of animal occupies a unique niche which characterizes its relationship with the dietary resources available in the environment (BRADLEY; BRADLEY 1985). While an optimal environment might offer sufficient resources for the coexistence of closely-related species, in practice, niche partitioning is often based on spatial and/or temporal differentiation, including the occupation of distinct microhabitats (SHOENER, 1974; ROSS, 1986). In this context, reliable data on feeding ecology may be important for the understanding of the factors that segregate sympatric species (GERKING, 1994)
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
