Diet and body shape among populations of Bryconamericus iheringii (Otophysi: Characidae) across the Campos Sulinos ecosystem

Abstract

Alterations in natural landscapes, mainly caused by anthropic pressures, have been threatening the world’s biomes, including aquatic environments and its biota. This study describes the diet of Bryconamericus iheringii, and how its body shape relates to environmental variables in populations of 22 streams. A wide array of food items were found, mainly composed of allochthonous plants (50.5%) and autochthonous invertebrates (25.2%). Even though food items remained almost the same, the predominant food group significantly differed among streams, mainly in relation to environmental characteristics. There was variation in body shape primarily associated with body depth and length of the pre-dorsal region; however, these differences did not correspond with streams. PLS-CA analyses indicated that environmental characteristics, such as substrate type, percentage of marginal vegetation have some influence over food items availability but not on body shape. This may be because B. iheringii is a non-specialist species capable of prey switching based on availability due to an intermediate body shape suited for generalist feeding habits.

Morphological traits correlated with resource partitioning among small characin fish species coexisting in a Neotropical river

“…Nevertheless, these traits are not restrictive for the use of varied resources as they become available by co‐occurring species, so long as interspecific interactions do not interfere with them. This explains the previous reports of high trophic plasticity in species of the same genera in other Neotropical environments (Silva et al, 2014, 2017), as well as the success of these species in altered environments (Dala‐Corte et al, 2017; Delariva et al, 2013; Kokubun et al, 2018).…”

“…The small size and overall body shape allows them to live in any one type of mesohabitat (rapids and backwaters). This design explain the habitat generalism previously observed for these genera (Bertaco, Ferrer, Carvalho, & Malabarba, 2016; Delariva et al, 2018; Kokubun et al, 2018).…”

“…In addition, fish of the family Characidae exhibit many diverse trophic modes (Hyatt, 1979). The genera Astyanax and Bryconamericus (“lambaris”; genera incertae sedis in Characidae) (Lima et al, 2003) form one of the fish clades most abundant in which dietary plasticity has been particularly well documented by previous studies (Bonato, Burress, Fialho, & Armbruster, 2018; Delariva, Hahn, & Kashiwaqui, 2013; Kokubun, Bonato, Burress, & Fialho, 2018; Oricolli & Bennemann, 2006; Pini et al, 2019; Portella, Lobón‐Cerviá, Manna, Bergallo, & Mazzoni, 2017; Silva, Gubiani, Neves, & Delariva, 2017) and has also been associated with the exploitation of alternative and seasonally varying resources in tropical systems (Neves et al, 2018; Silva, Gubiani, & Delariva, 2014).…”

Index of Biotic Integrity based on fish assemblages for pampean streams and its implementation along the Del Azul stream (Buenos Aires province, Argentina)

“…Thus, in degraded habitats, omnivores would be more represented than specialists (Karr et al, 1986). The captured species considered omnivorous were: Pimelodella laticeps (García et al, 2017), Rhamdia quelen (Gomes et al, 2000;Villares Junior & Goitein, 2015), Corydoras paleatus (Escalante, 1983), Loricariichthys anus (Rosso, 2006), Hypostomus commersoni (Menni, 2004), Astyanax fasciatus (Esteves, 1996;Vilella et al, 2002), Astyanax eigenmanniorum (Vilella et al, 2002), Bryconamericus iheringii (Lampert et al, 2004;Kokubun et al, 2018), Cheirodon interruptus (Escalante, 1987), Cyphocharax voga (Diovisalvi et al, 2010;Fernandez et al, 2012), Cyprinus carpio (Colautti & Remes Lenicov, 2001), Jenynsia multidentata (Iglesias et al, 2008;Quintans et al, 2009), Cnesterodon decemmaculatus (Quintans et al, 2009) and Mugil platanus (Oliveira & Soares, 1996).…”

DIET COMPOSITION, CONDITION FACTOR AND INTESTINAL COEFFICIENT OF THE FISH Astyanax lineatus REFLECT THE ANTHROPOGENIC EFFECTS ON STREAMS IN CENTRAL BRAZIL

“…This pollution alters the contribution of allochthonous and autochthonous resources available, which changes the feeding habits of fish (Ganassin et al 2020) and forces an adjustment in their diets when facing different habitat conditions (Alonso et al 2019, Oliveira et al 2021. Thus, species with trophic plasticity have the advantage of being able to shift their diet in response to environments with different shifts in resource availability (Welker & Scarnecchia 2006, Kokubun et al 2018, Oliveira et al 2021.…”