Stream Noise, Hybridization, and Uncoupled Evolution of Call Traits in Two Lineages of Poison Frogs: Oophaga histrionica and Oophaga lehmanni

Fernando Vargas-Salinas,Adolfo Amézquita,Nicolas Mathevon

doi:10.1371/journal.pone.0077545

Fernando Vargas-Salinas, Adolfo Amézquita + Show 1 more

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https://doi.org/10.1371/journal.pone.0077545

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Journal: PLoS ONE	Publication Date: Oct 23, 2013
Citations: 79	License type: CC BY 4.0

Affiliation: Universidad de Los Andes

Abstract

According to the acoustic adaptation hypothesis, communication signals are evolutionary shaped in a way that minimizes its degradation and maximizes its contrast against the background noise. To compare the importance for call divergence of acoustic adaptation and hybridization, an evolutionary force allegedly promoting phenotypic variation, we compared the mate recognition signal of two species of poison frogs (Oophaga histrionica and O. lehmanni) at five localities: two (one per species) alongside noisy streams, two away from streams, and one interspecific hybrid. We recorded the calls of 47 males and characterized the microgeographic variation in their spectral and temporal features, measuring ambient noise level, body size, and body temperature as covariates. As predicted, frogs living in noisy habitats uttered high frequency calls and, in one species, were much smaller in size. These results support a previously unconsidered role of noise on streams as a selective force promoting an increase in call frequency and pleiotropic effects in body size. Regarding hybrid frogs, their calls overlapped in the signal space with the calls of one of the parental lineages. Our data support acoustic adaptation following two evolutionary routes but do not support the presumed role of hybridization in promoting phenotypic diversity.

Highlights

Species exhibiting intraspecific geographic or microgeographic variation in habitat use offer excellent opportunities to understand the very initial steps of evolutionary divergence in auditory signals [1,2]
A form of sensory drive known as acoustic adaptation hypothesis implies that habitat characteristics such as background noise may evolutionarily shape auditory signals in a way that maximizes their contrast against the background noise [9,10,11]
Since populations differed in average body size (F = 91.52, DF = 4, P,0.001; Fig. 4), we repeated the discriminant analysis after controlling for both temperature and body size effects (Multiple regression, PC1: R2 = 0.431, F = 16,673, P,0.001; PC2: R2 = 0.278, F = 8.453, P = 0.001)

Summary

Introduction

Species exhibiting intraspecific geographic or microgeographic variation in habitat use offer excellent opportunities to understand the very initial steps of evolutionary divergence in auditory signals [1,2]. Sensory drive is widely recognized as the selective pressure of habitat characteristics on the evolution of communication systems [3,4]. Since habitats do vary geographically, local adaptations in mate recognition signals may promote reproductive isolation among populations and thereby speciation [5]. A form of sensory drive known as acoustic adaptation hypothesis ( termed signal structure hypothesis) implies that habitat characteristics such as background noise may evolutionarily shape auditory signals in a way that maximizes their contrast against the background noise [9,10,11]. The empirical evidence supporting adaptation in acoustic mating signals is surprisingly sparse compared to visual signals [6,12,13,14,15,16]

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