Diet-morphology relationship in the stream-dwelling characid Deuterodon stigmaturus (Gomes, 1947) (Characiformes: Characidae) is partially conditioned by ontogenetic development

Renato Bolson Dala-Corte,Eliane Regina Da Silva,Clarice Bernhardt Fialho

doi:10.1590/1982-0224-20150178

Renato Bolson Dala-Corte, Eliane Regina Da Silva + Show 1 more

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https://doi.org/10.1590/1982-0224-20150178

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Abstract

ABSTRACT We tested whether interindividual variations in diet composition within a population of Deuterodon stigmaturus can be explained by morphological differences between individuals, and whether diet-morphology relationships are dependent on the ontogenetic development. We analyzed diet of 75 specimens sampled in a coastal stream of Southern Brazil. Variation in stomach content was summarized with a Principal Coordinate Analysis (PCoA). The retained PCoA axes were tested as response to standard length (SL), and to values of intestine length (IL) and mouth length (ML) independent of body size, using linear mixed-effects models (LMM). The most consumed food items by D. stigmaturus were filamentous algae (41%), terrestrial plants (20.3%), detritus (12%), and aquatic invertebrates (8.8%). The LMMs showed that SL was positively related to consumption of terrestrial plants, whereas IL independent of SL was negatively related to aquatic invertebrates and positively related to filamentous algae. When body sized was held constant, ML was not related to diet variation. Interindividual diet differences conditioned to body size suggest that individuals shift their trophic niche and function in the ecosystem along the ontogenetic development. Relationships between intestine length and diet composition suggest interindividual differences in foraging ability and digestibility of distinct food items.

Highlights

Freshwater fishes can exhibit a high degree of intraspecific plasticity in their feeding habits (Winemiller, 1989; Horppila et al, 2000; Hegrenes, 2001; Svanbäck & Bolnick, 2007)
Regarding interindividual variation in diet and in morphology of characins, we aimed to investigate the feeding strategy of Deuterodon stigmaturus (Gomes, 1947), testing whether variations in stomach content is explained by interindividual differences in morphology, and whether morphology-diet relationships are related to ontogenetic development
First four axes of the Principal Coordinate Analyses (PCoA) summarized significant proportion of variation in diet composition based on the broken-stick criterion: 35.9% (PCo1); 12% (PCo2); 9.5% (PCo3) and 7.5% (PCo4)

Summary

Introduction

Freshwater fishes can exhibit a high degree of intraspecific plasticity in their feeding habits (Winemiller, 1989; Horppila et al, 2000; Hegrenes, 2001; Svanbäck & Bolnick, 2007). Characids may present intraspecific variation in the ingestion of food items according to longitudinal location within a given stream (Manna et al, 2012). In addition to diet variation between populations, great differences were evidenced in stomach content of characid individuals within a given population, such as those owing to seasonal availability of food (Vitule et al, 2008; Uieda & Pinto, 2011), or from ontogenetic shifts (Drewe et al, 2004; Vitule et al, 2008; Manna et al, 2012)

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