Ontogeny of feeding by Astyanax paris in streams of the Uruguay River Basin, Brazil

Abstract

Ontogeny of feeding by Astyanax paris in streams of the Uruguay River Basin, Brazil. We studied the ontogeny of feeding by Astyanax paris, an insectivorous characid fish from streams of the Uruguay River Basin in southern Brazil. Size-based differences in diet composition were evaluated using permutational multivariate analysis of variance (PERMANOVA). Six streams surveyed over twelve months yielded twenty specimens for analysis of stomach contents. Smaller individuals (SL ≤ 25 mm) consumed mainly aquatic insects. As body size increased, there was a gradual shift to a diet dominated by terrestrial insects. Ontogeny of feeding habitats thus changes the species' position in stream food webs. ResumenOntogenia de la alimentación de Astyanax paris en los arroyos de la cuenca fluvial del río Uruguay, en Brasil. Estudiamos la ontogenia de la alimentación de Astyanax paris, un pez carácido insectívoro de los arroyos de la cuenca del río Uruguay, en el sureste de Brasil. Las diferencias de la composición de la dieta en función del tamaño se analizaron mediante el análisis de varianza multivariante con permutaciones (PERMANOVA). Se muestrearon seis arroyos durante 12 meses y se obtuvieron 20 especímenes para analizar el contenido del estómago. Los individuos más pequeños (longitud estándar ≤ 25 mm) consumieron principalmente insectos acuáticos. A medida que aumentaba el tamaño corporal, se pasaba gradualmente a una dieta compuesta principalmente por insectos terrestres. En consecuencia, la ontogenia de los hábitats de alimentación cambia la posición de las especies en las redes tróficas de los arroyos.

Longitudinal and ontogenetic changes in feeding patterns of an insectivorous Crenuchidae in streams of southern Brazil

“…Therefore, C. pterostictum, like other insectivorous fish species, requires protection of its habitats. Such protection should consider not only the environmental quality of the streams but also the integrity of adjacent riparian vegetation Fialho 2016, Cavalheiro andFialho 2019). Recognizing that the effects of predator diversity extend beyond the predators' habitat and can propagate to adjacent ecosystems due to the cascade effect between aquatic and terrestrial food webs, underscores the interconnectedness of riparian habitats (Wesner 2012).…”

“…This differentiation in dietary preferences within a species is often influenced by variations in energy demands and morphological limitations (Abelha et al 2001). Such differential use of food resources is a common strategy among freshwater fish species, aimed at mitigating trophic niche overlap between juvenile and adult individuals (Rudolf and Lafferty 2011, Russo et al 2014, Cavalheiro and Fialho 2016, Dala-Corte et al 2016, Cavalheiro and Fialho 2019. Throughout our study, we observed a discernible shift in the feeding behavior of C. pterostictum, characterized by a decrease in the consumption of smaller-sized items, such as autochthonous Chironomidae, and a concurrent increase in the intake of larger insects, including autochthonous Simulidae, Trichoptera, Ephemeroptera, Plecoptera, Psychodidae, and Psphenidae.…”

“…Most teleosts display considerable feeding versatility (Abelha et al 2001). Several studies have reported ontogenetic dietary changes as a common pattern among neotropical freshwater fishes (Motta and Uieda 2004, Adite et al 2005, Wolff et al 2009, Cavalheiro and Fialho 2016, Dala-Corte et al 2016, Dias et al 2017, Cavalheiro and Fialho 2019. The variation in feeding habitats during a species' development illustrates an adaptation related to reduced competition, meeting physiological needs associated with migration, sexual maturation, and reproduction (Braga andBraga 1987, Motta andUieda 2004).…”

Feeding ecology of Eigenmannia desantanai (Gymnotiformes: Sternopygidae) in southern Pantanal, Brazil

“…Other important results indicated higher food intake during the flood season and by larger fish, once the increase of available area for feeding (in the flood period) also offer new habitats for foraging by E. desantanai. Larger fishes also have a larger mouth and consequently they can consume prey that is not available for smaller individuals; moreover, they have higher energy requirements to maintain their metabolism (Quirino et al, 2017;Cavalheiro & Fialho, 2019).…”