Reconciling Molecular with Biological and Morphological Data Towards an Integrative Analysis of the Evolutionary Biology of Chafers

Abstract

The research constituting this thesis acts at the interface of multiple disciplines related to biodiversity, combining data from morphology, genetics, geography, and ecology. Seven independent chapters (chapter II – chapter VIII) deal with diverse topics from a traditional taxonomic revision complemented by molecular phylogenetic analyses, over species delimitation and evolutionary studies of morphological diversification at different taxonomic scales, to population level landscape genetics integrating ecological niche modeling. Given the difficulties associated with a megadiversity of taxonomically challenging species and yet rarely used high dimensional trait data in comparative analyses, innovative methods were employed and tested, often pushing the limits of currently available methods.<br /> The subject of all studies were herbivore scarabs which represent one of the most diverse groups of living organisms. This property rendered them particularly suitable for the investigation of biodiversity-related questions. Three of the major known mechanisms for diversification of life were identified to have had potential impact: evolutionary key innovations, entry into new adaptive zones, and sexual selection. The former two of them were found in a single tribe of herbivore scarabs, the Sericini. The vast variability in their male genitalia, rendered a diversifying impact of sexual selection likely as well.<br /> Accurate delimitation of species and handling of taxonomic implications provided a proper basis for evolutionary research. The thesis thus contributes to the understanding of the hyper-diversity of herbivore scarabs, which might be explained by a series of major diversifying events and mechanisms, and provides a first step to the conservation of this diversity in South Africa.