Alimentación del pez insectívoro neotropical Creagrutus bolivari (Pisces: Characidae) según los métodos gráfico y de importancia relativa

Abstract

The diet of the neotropical insectivorous fish Creagrutus bolivari (Pisces: Characidae) according to the "graphic" and "relative importance" methods. The diet of a neotropical fish species (Creagrutus boli-vari) was studied using different methods: the Cortés 1997 graphic method and two relative importance indexes, one designed by George and Hadley in 1979 (% RI i) and another proposed by Cortés in 1997 (% IRI i). Only discrete prey (aquatic and terrestrial invertebrates) were used in the diet analysis. The occurrence (% A), number (% N) and weight (% G) frequencies were estimated for each food item. A total of 240 specimens (size range from 25.3 to 64.7 mm standard length) were analyzed. For values of % A > 50 %, % IRI i was higher than % RI i with an opposite trend (up to 130 times) for values of % A < 50 %. % IRI i overestimated the relative importance of prey for high values of % A, while it underestimated the relative importance of prey for low values of % A, showing a nonlinear relationship to % A. The variables used in the Cortés graphic method are insufficient to evaluate predator feeding strategy (generalization versus specialization). Therefore, we suggest including other variables, such as population and individual trophic niche breadth and a suitable field sampling record. An extended sampling record is necessary to classify prey as rare or dominant according to Cortés' classification. The indexes of relative importance and graphic method are complementary. Compound indexes that comprise mass, number, and occurrence provide a more accurate description of diet and allow comparative studies. The graphic analysis is easy to interpret and helps in the evaluation of prey importance and predator feeding strategy.

Hyphessobrycon platyodus (Teleostei: Characiformes), a new species from the Rio Madeira basin, Brazil, with comments on how multicuspid teeth relate to feeding habits in Characidae

“…(Sabino & Zuanon, ; Mérona et al ., ; Silva et al ., ), Creagrutus spp. (Ortaz et al ., ; Moraes et al ., ), Hemigrammus spp. (Sabino & Zuanon, ; Casatti et al ., ; Novakowski et al ., ; Ximenes et al ., ; Gonçalves et al ., ), Hyphessobrycon spp.…”

Hábitos tróficos del lenguado Citharicthys gilberti (Paralichthyidae) y su relación con las dinámica ambiental en la Bahía de Buenaventura, Pacífico colombiano

“…Estos tres porcentajes son comúnmente usados en estudios tróficos de peces (Sá et al, 2006;Navia et al, 2014;Garay et al, 2018 ). Sin embargo, cada uno de los porcentajes mencionados no representa un análisis completo, debido a que ítems muy numerosos y pequeños podrían influir en la importancia de ítems grandes y poco abundantes; así mismo, en el análisis gravimétrico se le podría dar mayor relevancia a un organismo pesado, por esa razón, es necesario el análisis conjunto de varios indicadores, para representar de forma más completa los procesos tróficos (Duque et al, 1996;Labbé y Arana, 2001;Ortaz et al, 2006 ). Para ello, se utilizaron los siguientes índices:…”

“…In addition, a gravimetric analysis might exaggerate the importance of a heavy organism. For this reason, several indicators should be analyzed together in order to represent the trophic processes in the most complete way possible (Duque et al, 1996;Labbé and Arana, 2001;Ortaz et al, 2006 ). The following indicators were used for the purpose:…”