Rapid diversification of colouration among populations of a poison frog isolated on sky peninsulas in the central cordilleras of Peru

Abstract

Aim Comparison of Epipedobates bassleri (Myers, 1987), which occurs on highaltitude mountain ridges ('sky peninsulas') in the Andean transition zone and demonstrates high levels of divergence in colouration among populations, and Epipedobates hahneli (Schulte, 1999), which occurs throughout the lowland regions of the Amazon basin and is morphologically conserved, using phylogenetic analysis of mitochondrial sequence data and comparison of colour pattern.Location Central cordilleras of Peru (near Tarapoto, San Martin).Methods DNA was extracted from individuals of E. bassleri from the central cordilleras of Peru, and from individuals of E. hahneli from across Peru. The cytochrome b mitochondrial gene region was amplified and sequenced for individuals of each species, and phylogenetic analysis was carried out using Bayesian inference. Genetic distances among populations and geographic distances of each species were examined and compared using Mantel tests. Parametric bootstrapping was used to test the monophyly of E. bassleri. ResultsEpipedobates bassleri formed a well-supported monophyletic group and showed higher levels of genetic divergence among populations than was shown among populations of E. hahneli from the same region. Distinct clades representing different geographic regions were recovered for E. hahneli. Levels of divergence among more geographically distant populations of E. hahneli were higher than levels of divergence among E. bassleri populations. We found a significant correlation between genetic divergence and geographic distance as measured along a 1000-m contour line, but not as measured by direct routes (crossing putative biogeographical barriers).Main conclusions Levels of genetic divergence were higher among populations of morphologically conservative E. hahneli than among populations of morphologically variable E. bassleri, suggesting rapid divergence in colouration among populations of E. bassleri. These patterns support previous arguments concerning the role of the montane transition zone between the high mountains and lowlands in divergence and speciation. High levels of both genetic and phenotypic divergence among populations of E. bassleri indicate that ecological or behavioural factors may be responsible for the high levels of colour variation seen among E. bassleri, but not among E. hahnleli, populations.

Molecular phylogeography and population structure of a mid-elevation montane frog Leptobrachium ailaonicum in a fragmented habitat of southwest China

“…2006), and thus considered the cause of allopatric isolation and lineage split. The same pattern has been observed for several species of plants (Assefa et al, 2007), arthropods (Masta, 2000;Ponniah, 2002;Martin, 2004, 2005;Smith and Farrell, 2005;Finn et al, 2006;Mark and Jane, 2006), amphibians (Doak, 2005;Roberts et al, 2007), and mammals (Yuan et al, 2006), to name a few, indicating that lowland areas are barriers to contemporary dispersal and were effective barriers to ancestral gene flow.…”

Detection experiments with humans implicate visual predation as a driver of colour polymorphism dynamics in pygmy grasshoppers

“…The efficacy of (most types of) protective coloration depends on the visual properties of the animal colour pattern relative to properties of the visual background where the animals live, and this offers excellent opportunities for investigations of evolution of local adaptations [4-6], evolutionary shifts in response to environmental changes e.g., [7-10], and for studies of factors that influence the maintenance and dynamics of polymorphisms e.g., [7,11]. …”

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

“…color and pattern) communication signals [32], [35], [36] that are heritable ([37], [38], Amézquita, unpublished data) and often exhibit intraspecific geographic variation [32], [39]. Among the mechanisms allegedly promoting geographic variation in their complex signals are divergent female choice preferences, adaptation to local predators, mimetic processes, and genetic drift [32], [39]–[41]. We expect here to add to this knowledge by testing the simultaneous effect of natural selection represented by stream noise and hybridization in the evolution of an auditory signal.…”