Dissertations, Theses, and Capstone Projects

Date of Degree

5-2015

Document Type

Dissertation

Degree Name

Ph.D.

Program

Biology

Advisor

David J. Lohman

Subject Categories

Agriculture | Animal Sciences | Biology | Zoology

Keywords

biogeography; Indo-Australian Archipelago; Pteropodidae; Pteropus; Southeast Asia; systematics

Abstract

Flying foxes (Pteropus) are a genus of Old World fruit bats that are important seed dispersers and pollinators for plants native to the 200,000+ islands in Southeast Asia, yet they are some of the most poorly known bats in the world. They comprise some of the largest known bat species, and are morphologically relatively conserved on the genus level. Pteropus is the most species-rich genus within Pteropodidae, though the origin for this diversity remains incompletely understood. In Chapter 1, I discuss the importance of Pteropus to the ecosystem and as reservoir hosts. In Chapter 2, a molecular phylogeny is presented with Pteropus species organized into fewer species groups than recognized from previous research that better reflected the comprehensive dataset. An increase in relative divergence rate was detected within Pteropus during the Pliocene that led to rapid radiations in three species groups. Additionally, discordant signals from nuclear and mitochondrial genes suggested incomplete lineage sorting and hybridization were present, likely as a result of the young clade age, low genetic variability, and rapid diversification of the genus. In Chapter 3, using the species tree generated in Chapter 2, I tested biogeographic mechanisms and scenarios that resulted in current distributions of Pteropus species using several ancestral area reconstruction methods. Dispersal and founder-event speciation were both important mechanisms through which species expanded into new areas. Wallacea was an integral part of the evolutionary history of Pteropus, and likely the region of origin, a new result uncovered largely a product of the increased taxonomic and geographic sampling. I then used a combination of phylogenetics and population genetics to determine the population connectivity of two commonly studied Pteropus hosts that are of interest to the disease ecology community, P. vampyrus (Chapter 4) and P. alecto (Chapter 5). Host metapopulation dynamics are important for predictions of pathogen diversity, aggressiveness, and transmission. Pteropus vampyrus and P. alecto highlight differences in management strategies needed and pathogen model predictions. Chapter 6 presents a general discussion regarding these findings and future directions for research.

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