Uso do alimento por duas espécies simpátricas de Moenkhausia (Characiformes, Characidae) em um riacho da Região Centro-Oeste do Brasil

Abstract

ABSTRACT. Food used by two sympatric species of Moenkhausia (Characiformes, Characidae), in a stream of centerwestern Brazil. This study evaluated the seasonality in the diet of Moenkhausia dichroura (Kner, 1858) and M. sanctaefilomenae (Steindachner, 1907), sympatric species of the Cancela stream, state of Mato Grosso, Brazil. Regardless of the seasonal period, allochthonous food source predominated in the diet of both species (>50% of all items consumed) and among these terrestrial insects were the dominant resource. However, aquatic insects were important in the diet of M. dichroura as well. Hymenoptera (Formicidae) was the dominant item to both species, thus they were characterized as terrestrial insectivorous. The restricted diet of these species is confirmed by the trophic niche breadth, whose values were in general low: Ba=0.26 to M. dichroura in both periods and Ba=0.41 and 0.38 in the dry and rainy period, respectively, to M. sanctaefilomenae. The feeding overlap was high in the rainy period (O jk =0.75) and intermediate in the dry period (O jk =0.41), showing that the food partitioning between species was larger in this period. KEYWORDS. Diet, Moenkhausia dichroura, M. sanctaefilomenae, coexistence.RESUMO. Esse estudo avaliou sazonalmente a dieta de Moenkhausia dichroura (Kner, 1858) e M. sanctaefilomenae (Steindachner, 1907), coletadas em simpatria no riacho Cancela, Mato Grosso, Brasil. Independente do período hidrológico, alimentos de origem alóctone predominaram na dieta de ambas as espécies (>50% do total de itens consumidos), sendo insetos terrestres o recurso principal, embora, para M. dichroura insetos aquáticos tenham contribuído na dieta também. Hymenoptera (Formicidae) foi o alimento mais consumido, sendo ambas as espécies caracterizadas como insetívoras terrestres. A dieta restrita dessas espécies é confirmada pelos baixos valores de amplitude de nicho trófico: Ba=0,26 para M. dichroura em ambos os períodos e Ba=0,41 no período de seca e 0,38 no período de chuva, para M. sanctaefilomenae. A sobreposição alimentar foi elevada no período de chuva (O jk =0,75) e apresentou valor intermediário no período de seca (O jk =0,41), evidenciando maior partilha do alimento entre as espécies neste período. PALAVRAS-CHAVE.Dieta, Moenkhausia dichroura, M. sanctaefilomenae, coexistência.

Importance of allochthonous resources in the diet ofAstyanax aff. fasciatus (Osteichthyes: Characidae) in streams: a longitudinal approach

“…Subsidies as invertebrates can represent up to half of the energy in the diet of stream fish (Masson & Macdonald 1982), indicating that in these environments the availability of prey induce higher consumption (Rezende & Mazzoni, 2006), or the fishes have a preference for these organisms (Main & Lyon 1988, Garman 1991. The importance of subsidies in the diet of stream fish has been frequently reported in tropical regions (Henry et al 1994, Vitule et al 2008, Wolff et al 2009, Tó foli et al 2010, Manna et al 2012, Small et al 2013.…”

Food-resource partitioning among fish species from a first-order stream in northwestern Paraná, Brazil

“…Studies on trophic ecology have revealed a dietary pattern for fish from Neotropical streams, where the diet is mainly based on allochthonous food resources (Casatti, 2002;Mazzoni et al, 2010a;Tófoli et al, 2010), with the maximum use of environmental resources (Brandão-Gonçalves et al, 2010;Rezende et al, 2011) and high trophic plasticity of the species (Lowe-McConnell, 1999;Abelha et al, 2001).…”

“…These changes influence the contribution of allochthonous resources from the terrestrial environment, which are essential for stream fish (Alvim & Peret, 2004;Rezende & Mazzoni, 2005;Winemiller et al, 2008;Tófoli et al, 2010). Riparian vegetation is of paramount importance in sustaining these ecosystems, by influencing the transfer of solar energy to the environment, intercepting sediments that enter streams, and providing food and shelter for the fish fauna (Pusey & Arthington, 2003;Abilhoa et al, 2008).…”

Feeding ecology of Dash-dot Tetra Hemigrammus belottii(Steindachner 1882) (Characiformes: Characidae) in the streams of the Urucu River basin, central Amazonia, Brazil

“…This material may represent dietary items (Sabino & Castro 1990, Dufech et al 2003, Tófoli et al 2010, as recorded in the present study, or it may act indirectly by providing habitats for the aquatic invertebrates that represent a dietary resource for the fishes, such as floating logs and submerged leaf litter (Pusey & Arthington 2003).…”