Delimitación de una especie nueva de Geometridae (Lepidoptera) del desierto de Atacama y evaluación de los efectos del paisaje sobre sus patrones y procesos microevolutivos.
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Date
2026
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Universidad de Concepción
Abstract
Las zonas ribereñas del Desierto de Atacama y las áreas adyacentes de la Cordillera de los Andes albergan una diversidad de especies y poblaciones únicas de insectos que han sido pobremente descritas. En estos ecosistemas hiperáridos, la extrema escasez de agua, la distribución espacial parcheada de los recursos y la presencia de barreras geográficas generan condiciones que pueden influir profundamente en la dispersión, el flujo génico y los procesos microevolutivos de las poblaciones. Esta dinámica del paisaje desértico constituye un contexto clave para comprender la sistemática y genética de poblaciones de los insectos que lo habitan.
En esta investigación doctoral se presenta un estudio de la sistemática y genómica poblacional de Physocleora polyphaga Vargas-Ortiz & Parra sp. nov., una especie polífaga de la familia Geometridae estrechamente asociada a plantas nativas, distribuida en valles costeros y laderas andinas del extremo norte de Chile.
En el Capítulo 1, se propone una nueva especie del género Physocleora Warren, 1897, a través de la descripción de características morfológicas diagnósticas, algunos aspectos ecológicos relevantes y una reconstrucción de la historia evolutiva de la especie dentro del género Physocleora Warren, 1897, basada en secuencias del marcador molecular COI (DNA barcode). Para validar la hipótesis de conespecificidad entre los especímenes analizados, se emplearon métodos de delimitación de especies basados en distancias genéticas y análisis filogenéticos.
En el Capítulo 2, se realizó un estudio microevolutivo con el objetivo de explorar la genómica poblacional de esta especie recientemente descrita, así como responder preguntas relacionadas con la distribución geográfica de su diversidad genómica y patrones de selección en dos valles costeros del Desierto de Atacama y una zona de la precordillera. Para ello, se emplearon polimorfismos de nucleótido simple (SNPs), analizados mediante diversos enfoques bioestadísticos. Los análisis genómicos revelaron ausencia de señales de selección que pudieran influenciar la divergencia entre poblaciones. Los resultados evidenciaron un patrón de aislamiento asociado a barreras geográficas entre las tres poblaciones estudiadas, descartando simultáneamente patrones de aislamiento por distancia geográfica y rutas de menor costo. Asimismo, los análisis evidenciaron una leve diferenciación genética entre las poblaciones, lo que sugiere un proceso reciente de divergencia poblacional. En conjunto, la comparación entre marcadores mitocondriales (COI) y nucleares (SNPs) reveló una concordancia parcial entre ambos capítulos, sugiriendo que estos marcadores capturan procesos evolutivos que operan a distintas escalas temporales y espaciales, posiblemente asociados a la inestabilidad de los ecosistemas de valles costeros y a patrones de dispersión diferencial entre sexos. Estos resultados resaltan que el paisaje del Desierto de Atacama y el área adyacente de precordillera—caracterizados por parches de vegetación aislados y barreras geográficas pronunciadas—pueden moldear procesos microevolutivos en insectos nativos, aportando un marco para futuras investigaciones en sistemática, biogeografía y genómica en ecosistemas áridos.
The riparian zones of the Atacama Desert and adjacent areas of the Andes foothills harbor a diversity of unique insect species and populations that remain poorly described. In these hyperarid ecosystems, extreme water scarcity, the patchy spatial distribution of resources, and the presence of geographic barriers create conditions that can profoundly influence dispersal, gene flow, and microevolutionary processes in populations. This desert landscape dynamic provides a key context for understanding the systematics and population genetics of the insects inhabiting it. This doctoral research presents a study on the systematics and population genomics of Physocleora polyphaga Vargas-Ortiz & Parra sp. nov., a polyphagous species of the family Geometridae closely associated with native plants, distributed across coastal valleys and Andean slopes in northern Chile. In Chapter 1, a new species of the genus Physocleora Warren, 1897, is proposed through the description of diagnostic morphological characteristics, some relevant ecological aspects, and a reconstruction of the species' evolutionary history within the genus Physocleora Warren, 1897, based on COI molecular marker sequences (DNA barcode). To validate the hypothesis of conspecificity among the analyzed specimens, species delimitation methods based on genetic distances and phylogenetic analyses were employed. In Chapter 2, a microevolutionary study was conducted to explore the population genomics of this recently described species and to answer questions related to the geographic distribution of its genomic diversity and selection patterns in two coastal valleys of the Atacama Desert and a pre-Andean zone. Single nucleotide polymorphisms (SNPs) were analyzed using various biostatistical approaches. Genomic analyses revealed an absence of selection signals that could influence divergence among populations. The results showed an isolation pattern associated with geographic barriers among the three studied populations, while simultaneously ruling out isolation patterns based on geographic distance and least-cost routes. Furthermore, the analyses revealed slight genetic differentiation among the populations, suggesting a recent population divergence process. Overall, the comparison between mitochondrial (COI) and nuclear (SNP) markers revealed partial agreement between the two chapters, suggesting that these markers capture evolutionary processes operating at different temporal and spatial scales, possibly associated with the instability of coastal valley ecosystems and differential dispersal patterns between sexes. These results highlight that the Atacama Desert landscape and the adjacent pre-Andean area—characterized by isolated vegetation patches and pronounced geographical barriers—can shape microevolutionary processes in native insects, providing a framework for future research in systematics, biogeography, and genomics in arid ecosystems.
The riparian zones of the Atacama Desert and adjacent areas of the Andes foothills harbor a diversity of unique insect species and populations that remain poorly described. In these hyperarid ecosystems, extreme water scarcity, the patchy spatial distribution of resources, and the presence of geographic barriers create conditions that can profoundly influence dispersal, gene flow, and microevolutionary processes in populations. This desert landscape dynamic provides a key context for understanding the systematics and population genetics of the insects inhabiting it. This doctoral research presents a study on the systematics and population genomics of Physocleora polyphaga Vargas-Ortiz & Parra sp. nov., a polyphagous species of the family Geometridae closely associated with native plants, distributed across coastal valleys and Andean slopes in northern Chile. In Chapter 1, a new species of the genus Physocleora Warren, 1897, is proposed through the description of diagnostic morphological characteristics, some relevant ecological aspects, and a reconstruction of the species' evolutionary history within the genus Physocleora Warren, 1897, based on COI molecular marker sequences (DNA barcode). To validate the hypothesis of conspecificity among the analyzed specimens, species delimitation methods based on genetic distances and phylogenetic analyses were employed. In Chapter 2, a microevolutionary study was conducted to explore the population genomics of this recently described species and to answer questions related to the geographic distribution of its genomic diversity and selection patterns in two coastal valleys of the Atacama Desert and a pre-Andean zone. Single nucleotide polymorphisms (SNPs) were analyzed using various biostatistical approaches. Genomic analyses revealed an absence of selection signals that could influence divergence among populations. The results showed an isolation pattern associated with geographic barriers among the three studied populations, while simultaneously ruling out isolation patterns based on geographic distance and least-cost routes. Furthermore, the analyses revealed slight genetic differentiation among the populations, suggesting a recent population divergence process. Overall, the comparison between mitochondrial (COI) and nuclear (SNP) markers revealed partial agreement between the two chapters, suggesting that these markers capture evolutionary processes operating at different temporal and spatial scales, possibly associated with the instability of coastal valley ecosystems and differential dispersal patterns between sexes. These results highlight that the Atacama Desert landscape and the adjacent pre-Andean area—characterized by isolated vegetation patches and pronounced geographical barriers—can shape microevolutionary processes in native insects, providing a framework for future research in systematics, biogeography, and genomics in arid ecosystems.
Description
Tesis presentada para optar al grado de Doctor/a en Sistemática y Biodiversidad.
Keywords
Lepidópteros, Dispersión, Evolución, Genética