INVESTIGADORES
SAN BLAS Diego German
congresos y reuniones científicas
Título:
Species delimitation and tree inference under the multispecies coalescent model in Eucecidoses Brèthes (Lepidoptera: Cecidosidae)
Autor/es:
DA SILVA, GABRIELA T.; PASE, RAMOIM B.; SAN BLAS, GERMÁN; GISLENE L. GONÇALVES; GILSON R. P. MOREIRA
Lugar:
Tucumán
Reunión:
Encuentro; V Encuentro de Lepidoptera Neotropicales; 2015
Institución organizadora:
Universidad Nacional de Tucumán
Resumen:
Eucecidoses Brèthes(Lepidoptera: Cecidosidae) is a monotypic, Neotropical genus of micro moths,whose larvae induces galls on Schinus polygamus (Cavanilles) Cabrera (Anacardiaceae),abridging only E. minutanus Brèthes. However, recent evidences from morphological characters of immature and adult stages have raised doubts about its taxonomy status.In addition, preliminary results on DNA barcode reveal at least two highly divergent lineages. Herein we investigated the genetic structure among populations of E. minutanus using the multispecies coalescent model(MSC), which aim to identify independently evolving lineages, accounting for migration between populations. We sequenced ca. 3 Kb base pairs of mitochondrial genes (CoI, CoII, and rRNA 16S) in 73 specimens from 22 populations across different ecoregions in Argentina (Buenos Aires, Mendoza and Tucumán) and Southern Brazil (Rio Grande do Sul, Santa Catarina, Paraná, São Paulo and Minas Gerais). Joint Bayesian species delimitation and species tree estimation was conducted using the program BPP. The method uses the MSC to compare different models of species delimitation and species phylogeny in a Bayesian framework, accounting for incomplete lineage sorting due to ancestral polymorphism and gene tree-species tree conflicts. The population size parameters (θs) were assigned the gamma prior G (2, 1000), with mean 2/2000 = 0.001. The divergence time at the root of the species tree (τ0) was assigned the gamma prior G (2, 1000), while the other divergence time parameters were assigned the Dirichlet prior. We also inferred a haplotype network in SplitsTree 4.13.1 with calculated uncorrected p-distances and used the Neighbor Net algorithm to reconstruct the genealogy. The phylogenetic reconstruction recovered six clades. The BPP analysis identified six independent lineages, with high support for each of them (P=0.96). Thehaplotype network yielded well resolved and robust relationships between lineages, with a clear structuration per ecoregions: Puna, Yungas, Pampas and Araucaria Forest. In addition to molecular clustering, a combination of other lines of evidence, such as a complete character-based diagnosis on larvae and adult morphology, and host-plant differences, are essential to describe these lineages as potential new taxa. Morphological studies have been carrying out in specimens from each of the recognized clusters, as well as host plantco-phylogeny reconstruction. Further results will point out whether (and which)groups found within Eucecidoses should be raised to the species level or stay at the population level.