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Accueil du site → Master → Etats Unis → 2012 → Phylogeography of Pogonomyrmex barbatus and P. rugosus Harvester Ants : A Complex Regional History of Ancient Vicariance and Recent Expansion in Arid- Adapted Insects, and Implications for the Success of Cryptic Hybrid Lineages with GCD

Arizona State University (2012)

Phylogeography of Pogonomyrmex barbatus and P. rugosus Harvester Ants : A Complex Regional History of Ancient Vicariance and Recent Expansion in Arid- Adapted Insects, and Implications for the Success of Cryptic Hybrid Lineages with GCD

Mott, Brendon Michael

Titre : Phylogeography of Pogonomyrmex barbatus and P. rugosus Harvester Ants : A Complex Regional History of Ancient Vicariance and Recent Expansion in Arid- Adapted Insects, and Implications for the Success of Cryptic Hybrid Lineages with GCD

Auteur : Mott, Brendon Michael

Université de soutenance : Arizona State University

Grade : Master of Science M.S. Biology 2012

Résumé
Here I present a phylogeographic study of at least six reproductively isolated lineages of harvester ants within the Pogonomyrmex barbatus and P. rugosus species group. The genetic and geographic relationships within this clade are complex : four of the identified lineages are divided into two pairs, and each pair has evolved under a mutualistic system that necessitates sympatry. These paired lineages are dependent upon one another because interlineage matings within each pair are the sole source of hybrid F1 workers ; these workers build and sustain the colonies, facilitating the production of the reproductive caste, which results solely from intralineage fertilizations. This system of genetic caste determination (GCD) maintains genetic isolation among these closely related lineages, while simultaneously requiring co-expansion and emigration as their distributions have changed over time. Previous studies have also demonstrated that three of the four lineages displaying this unique genetic caste determination phenotype are of hybrid origin. Thus, reconstructing the phylogenetic and geographic history of this group allows us to evaluate past insights and plan future inquiries in a more complete historical biogeographic context. Using mitochondrial DNA sequences sampled across most of the morphospecies’ ranges in the U.S. and Mexico, I employed several methods of phylogenetic and DNA sequence analysis, along with comparisons to geological, biogeographic, and phylogeographic studies throughout the sampled regions. These analyses on Pogonomyrmex harvester ants reveal a complex pattern of vicariance and dispersal that is largely concordant with models of late Miocene, Pliocene, and Pleistocene range shifts among various arid-adapted taxa in North America

Mots Clés : Biology / Molecular biology / Ecology / Biogeography / Genetic Caste Determination / Hybridization / North America / Phylogeography / Pogonomyrmex

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Page publiée le 8 novembre 2012, mise à jour le 5 avril 2019