Vol 14 No 1 (2019)
Articles

Does color polymorphism affect the predation risk on Phalotris lemniscatus (Duméril, Bibron and Duméril, 1854) (Serpentes, Dipsadidae)?

Fernanda de Avila
Laboratório de Ecologia de Vertebrados Terrestres, Programa de Pós-Graduação em Biologia, Universidade do Vale do Rio dos Sinos, Avenida Unisinos, 950, Cristo Rei, CEP 93022-970, São Leopoldo, RS, Brasil Laboratório de Genética e Biologia Molecular, Programa de Pós-Graduação em Biologia, Universidade do Vale do Rio dos Sinos, Avenida Unisinos, 950, Cristo Rei, CEP 93022-970, São Leopoldo, RS, Brasil
Juliano Oliveira
Laboratório de Ecologia Vegetal, Programa de Pós-Graduação em Biologia, Universidade do Vale do Rio dos Sinos, Avenida Unisinos, 950, Cristo Rei, CEP 93022-970, São Leopoldo, RS, Brasil
Mateus de Oliveira
Laboratório de Ecologia de Vertebrados Terrestres, Programa de Pós-Graduação em Biologia, Universidade do Vale do Rio dos Sinos, Avenida Unisinos, 950, Cristo Rei, CEP 93022-970, São Leopoldo, RS, Brasil
Marcio Borges-Martins
Laboratório de Herpetologia, Departamento de Zoologia, Instituto de Biociências, Universidade Federal do Rio Grande do Sul, Avenida Bento Gonçalves, 9500, Agronomia, CEP 91501-970, Porto Alegre, RS, Brasil
Victor Hugo Valiati
Laboratório de Genética e Biologia Molecular, Programa de Pós-Graduação em Biologia, Universidade do Vale do Rio dos Sinos, Avenida Unisinos, 950, Cristo Rei, CEP 93022-970, São Leopoldo, RS, Brasil
Alexandro Tozetti
Laboratório de Ecologia de Vertebrados Terrestres, Programa de Pós-Graduação em Biologia, Universidade do Vale do Rio dos Sinos, Avenida Unisinos, 950, Cristo Rei, CEP 93022-970, São Leopoldo, RS, Brasil
Published May 2, 2019

Abstract

The snake Phalotris lemniscatus is a polymorphic species regarding color, which varies between light shades with a yellow predominance (pale yellow-brown) to darker shades with a red predominance (red-dark). Pale yellow-brown individuals are more frequent in coastal populations while there is a tendency of increasing the frequency of red-dark morphs in inland areas. Considering the variation in substrate color along the species distribution (light/sandy on the coast to reddish and dark/argillaceous in inland areas), we raise the hypothesis that the predation rate of each morph would be lower in sites were its crypsis potential is higher. If correct, this hypothesis would reinforce the idea that the predation risk is one of the factors influencing the spatial structuring in morph frequency distributions in populations of P. lemniscatus. To test this hypothesis, we performed a field experiment using plasticine P. lemniscatus artificial models that represent two morphs: red-dark and pale yellow-brown. The models were distributed in three localities where the following substrate types predominate: light (Coastal Site), intermediary (Lowland Site) and reddish dark (Highland Site). Our predictions were corroborated only at the coastal site, where the less cryptic morph was the most preyed one. We verified that there is a regional variation in the predation risk on different morphs. Thus, the possibility that the selective pressure by predators is a relevant element in the structuring of the frequencies of different morph populations of this species cannot be completely excluded.

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