Diet of two syntopic species of Crenuchidae (Ostariophysi: Characiformes) in an Amazonian rocky stream

Abstract

This study assessed the diet of two poorly known syntopic fish species of the family Crenuchidae, Characidium aff. declivirostre and Leptocharacidium omospilus, in a Presidente Figueiredo´ rocky stream, Amazonas, Brazil. The stomach contents were analyzed and their Frequency of Occurrence (FO %) and Relative Volume (Vol %) were combined in a Feeding Index (IAi). We examined 20 individuals of C. aff. declivirostre and 23 of L. omospilus. The Morisita-Horn Index was used to estimate the overlap between the diets of these species. Immature insects were the most valuable items consumed by both fish species. The diet of C. aff. declivirostre was mainly composed of larvae and pupae of Chironomidae, while L. omospilus predominantly consumed larvae of Hydroptilidae, Hydropyschidae and Pyralidae. Thus, both species were classified as autochthonous insectivorous. Characidium aff. declivirostre was considered a more specialized species, probably reflecting lower feeding plasticity or the use of more restricted microhabitats compared to L. omospilus. When the food items were analyzed at the family taxonomic level, the diet overlap between these species was considered moderate (Morisita-Horn Index = 0.4). However, a more thorough analysis, at the genus level, indicates a very low diet overlap. Therefore, we conclude that the feeding segregation between C. aff. declivirostre and L. omospilus may favor their co-existence, despite their high phylogenetic closeness. Keywords

The ecomorphological diversity of Amazonian stream fishes is constrained by phylogenetic relationships

“…Dietary and spatial resources are primary drivers of species' coexistence in vertebrates (Schoener 1974) and several studies present evidences of habitat segregation in Neotropical stream fishes (Brejão, Gerhard, and Zuanon 2013;Silva et al 2016;Soares et al 2017;Ferreira et al 2021). On the other hand, Ross (1986) suggested that food partitioning is more important than spatial segregation in fishes, which is supported for some Neotropical fish assemblages (Brazil-Sousa, Marques, and Albrecht 2009;Fernandes et al 2017;Barili et al 2011;Correa and Winemiller 2014). Our results highlight that the most important traits favoring spatial and trophic partitioning covary in Amazonian stream fishes, hence being both equally important for potential niche partitioning.…”

Influência da piscicultura de pequena escala em canais de igarapés sobre as categorias tróficas da ictiofauna Amazônica

“…Os igarapés de primeira ordem são sistemas alóctones muito dependentes das matas ripárias que servem como fonte de energia e nutrientes (KAWAGUCHI et al, 2003). Essa dependência já vem sendo descrita em vários trabalhos (ANJOS, 2005;SANTOS et al, 2015, FERNANDES et al, 2017. O estudo de Anjos ( 2005) descreve que as famílias Characidae, Lebiasinidae são sempre representativas nas categorias dos insetos alóctones, o que foi corroborado no presente estudo.…”

Ecologia Trófica De Peixes De Riacho: Uma Releitura 20 Anos Depois

“…Em riachos rochosos na Amazônia, Characidium aff. declivirostre (Characiformes, Crenuchidae) e Leptocharacidium omospilus (Characiformes, Crenuchidae) se alimentaram de larvas e pupas de Chironomidae, Hydroptilidae, Hydropyschidae e Pyralidae (Fernandes et al 2017), indicando comportamento de procura junto ao fundo e a tática do tipo "senta-e-espera", empregadas por espécies do gênero Characidium (Aranha et al 1998). Por outro lado, hábitos mais especializados, como herbivoria e piscivoria foram pouco relatados para as diferentes bacias consideradas, sendo essas guildas mais comuns na bacia Amazônica.…”