Includes copies of author's previously published works / Guano deposits in caves form a rich food resource supporting diverse arthropod communities. Guano piles consist of distinct micro - habitats, fresh, moist, highly basic guano and older, dry, slightly acidic guano. Micro - habitat variation is strongly controlled by seasonal guano deposition that, in turn, effects the structure of arthropod communities. The maternity chamber of Bat Cave, Naracoorte, South Australia, contains extensive guano deposits supporting 38 species from three classes and 12 orders. This community was studied to determine spatial and temporal variation of arthropod communities, and biogeographic relationships between different regions in Australia. Species richness forms a positive linear relationship with pH, in situ moisture content and guano deposition. Many species show strong associations with fresh guano and hence are strongly seasonal, although some species are present throughout the year. Arthropod community structure in winter was found to be more closely related to prior summer arthropod structure than to subsequent seasons. Starlight Cave near Warrnambool, western Victoria, the only other maternity site for Miniopterus schreibersii bassanii, contained 43 species from 39 families and 14 orders. Seven species are common to both caves. The community structure of Starlight Cave was found to be more homogeneous than Bat Cave with samples clustering by season rather than sample year as was the case at Bat Cave. Different cave morphology was found to significantly alter the micro - habitat conditions and, hence, community structure in Starlight Cave compared with Bat Cave. Migration of guano associated arthropods at local, regional and continental scales was assessed using mtDNA and allozyme electrophoresis the pseudoscorpion genus Protochelifer as a model organism. Phylogenetic tree reconstruction revealed a wide geographic distribution of cavernicolous species across southern Australia. Cave colonisation is believed to have occurred only once, followed by dispersal to the Nullarbor Plain and other caves in south - eastern Australia. Dispersal was possibly phoretic on cave bats or occurred prior to aridification of surface environments that currently restricts migration. The distribution of guano - associated arthropods from arid, semi - arid and monsoonal karst areas in Australia are compared with temperate south - eastern Australia. Different climatic areas show large biogeographical differences in community structure, although similar families ( Urodinychidae, Reduviidae, Anobiidae, Carabidae and Tineidae ) are present in many Australian guano communities. Several potential mechanisms of dispersal are discussed including phoresy, colonisation from soil, terrestrial migration and interstitial cavities. Endemism to specific caves cannot be definitely assigned to any species, although 13 species show restricted distribution. / Thesis (Ph.D.)--School of Earth and Environmental Sciences, 2006.