Trophic specialization and morphological divergence between two sympatric species in Lake Catemaco, Mexico
Por:
Patricia Ornelas-Garcia, Claudia, Cordova-Tapia, Fernando, Zambrano, Luis, Pamela Bermudez-Gonzalez, Maria, Mercado-Silva, Norman, Mendoza-Garfias, Berenit, Bautista, Amando
Publicada:
1 may 2018
Resumen:
The association of morphological divergence with ecological segregation among closely related species could be considered as a signal of divergent selection in ecological speciation processes. Environmental signals such as diet can trigger phenotypic evolution, making polymorphic species valuable systems for studying the evolution of trophic-related traits. The main goal of this study was to analyze the association between morphological differences in trophic-related traits and ecological divergence in two sympatric species, Astyanax aeneus and A. caballeroi, inhabiting Lake Catemaco, Mexico. The trophic differences of a total of 70 individuals (35 A. aeneus and 35 A. caballeroi) were examined using stable isotopes and gut content analysis; a subset of the sample was used to characterize six trophic and six ecomorphological variables. In our results, we recovered significant differences between both species in the values of stable isotopes, with higher values of d15N for A. caballeroi than for A. aeneus. Gut content results were consistent with the stable isotope data, with a higher proportion of invertebrates in A. caballeroi (a consumption of invertebrates ten times higher than that of A. aeneus, which in turn consumed three times more vegetal material than A. caballeroi). Finally, we found significant relationship between ecomorphology and stable isotopes (r =.24, p <.01), hence, head length, preorbital length, eye diameter, and d15N were all positively correlated; these characteristics correspond to A. caballeroi. While longer gut and gill rakers, deeper bodies, and vegetal material consumption were positively correlated and corresponded to A. aeneus. Our results are consistent with the hypothesis that morphological divergence in trophic-related traits could be associated with niche partitioning, allowing the coexistence of closely related species and reducing interspecific competition. © 2018 The Authors. Ecology and Evolution published by John Wiley & Sons Ltd.
Filiaciones:
Patricia Ornelas-Garcia, Claudia:
Univ Autonoma Mexico, Dept Zool, Inst Biol, Mexico City, DF, Mexico
Cordova-Tapia, Fernando:
Univ Autonoma Estado Morelos, Ctr Invest Biodiversidad & Conservac, Cuernavaca, Morelos, Mexico
Zambrano, Luis:
Univ Autonoma Mexico, Dept Zool, Inst Biol, Mexico City, DF, Mexico
Pamela Bermudez-Gonzalez, Maria:
UAQ, Programa Inst, Fac Ciencias Nat, Campus UAQ Juriquilla, Queretaro, Mexico
Mercado-Silva, Norman:
Univ Autonoma Estado Morelos, Ctr Invest Biodiversidad & Conservac, Cuernavaca, Morelos, Mexico
Mendoza-Garfias, Berenit:
Univ Autonoma Mexico, Dept Zool, Inst Biol, Mexico City, DF, Mexico
Bautista, Amando:
Univ Autonoma Tlaxcala, Ctr Tlaxcala Biol Conducta, Tlaxcala De Xicohtencatl, Tlaxcala, Mexico
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