In this dissertation I evaluated the ecological and evolutionary mechanisms that promote the spread of non-native parasites infecting novel hosts under contemporary and future climate conditions. Thorough assessment of the impact of introduced parasites and an understanding of the potential effects of climate change on parasite distributions and densities will promote effective conservation of native aquatic biodiversity. The spread of an introduced nematode parasite, Camallanus cotti, infecting the native Hawaiian stream fish, Awaous stamineus, across the Hawaiian Islands provided an opportunity to examine how biotic (densities of introduced & native hosts, individual host traits, genetic diversity) and environmental (land-use, water chemistry) factors promote novel host-parasite interactions. In addition to completing archipelago-wide surveys of parasite distributions and densities in native fish hosts, I characterized geographic patterns of genetic variation in C. cotti to assess gene flow, identify likely conduits of introduction and spread of the parasite across the archipelago. Finally, I utilized a natural precipitation gradient across the Hamakua coast on the island of Hawai`i, as a natural analog to conditions predicted by climate change, to assess the relationship between precipitation and infection of A. stamineus by C. cotti. I found the distribution C. cotti has become decoupled from that of the non-native hosts and that the parasite infects native fishes in remote, relatively pristine watersheds. The abundance, intensity, and prevalence of C. cotti infecting A. stamineus are influenced by a suite of factors, but notably parasitism increases with decreasing precipitation. This finding suggest that infection of native Hawaiian fishes by introduced parasites will increase if climate conditions change as expected. Genetic analysis indicates that C. cotti has spread across the archipelago following an initial introduction on O'ahu with subsequent dispersal to Maui and then underwent stepwise dispersal to other islands in the archipelago. Significant genetic structure also was detected across islands, suggesting that dispersal potential is constrained, which in turn suggests that remediation efforts focusing on invasion hotspots or areas of concern could be effective at reducing parasites loads in native fishes. / acase@tulane.edu

This thesis is a comprehensive treatment of the invasion genetics of two major Liposcelis pest species, Liposcelis bostrychophila Badonnel and L. decolor (Pearman), in Australian grain storage systems. Randomly amplified polymorphic DNA (RAPDs) and microsatellite DNA markers were used to investigate Liposcelis invasions in grain storage systems. The RAPD and microsatellite markers used provided insights into the genetic diversity of L. bostrychophila and L. decolor populations both in Australia and internationally, providing information integral to gaining an understanding of Liposcelis invasions in Australian grain storage systems. The thesis is divided into discrete chapters, and for each chapter an abstract is provided. Chapter 1 provides background on Liposcelis invasions in Australia in relation to the biology of Liposcelis species, the infrastructure of the Australian grain industry and the history of invasions in comparison to other invasive invertebrate species. The use of DNA and PCR technologies to investigate Liposcelis invasions are discussed and the aims and objectives of this thesis are introduced. Chapter 2 uses RAPDs to trace the geographic origin of L. bostrychophila populations in Australia from unknown geographic sources internationally. High levels of clonal genetic diversity among populations of L. bostrychophila in Australia and internationally were found. In addition, multiple introductions, from a wide range of international source populations were detected and this obscured our ability to accurately determine the geographic origin of L. bostrychophila in Australia. Given the high clonal genetic diversity found in populations of parthenogenetic L. bostrychophila in Australia, diagnostic Wolbachia PCR primers were used in Chapter 3 to investigate whether L. bostrychophila individuals from these populations were infected by Wolbachia and if infected, to investigate the strain of Wolbachia characteristic of Australian L. bostrychophila populations. Results from Chapter 3 provide the first evidence of multiple Wolbachia infection from strains A and B in Australian L. bostrychophila populations. Chapter 4 details the extensive molecular procedures undertaken to isolate microsatellite loci from Liposcelis decolor using both enrichment and nonenrichment methods. Microsatellite loci were optimised for use in PCR in single individuals following extensive troubleshooting. Troubleshooting efforts focused on elucidating the factors controlling the specificity, efficiency and sensitivity of the PCR to amplify small Liposcelis individuals known to be rich in lipids and proteins, all inhibitory to PCR. In Chapter 5 lipids and proteins were investigated from L. decolor and L. entomophila to determine total concentrations and characterize the lipids from these species. This chapter discusses whether the lipid and protein concentrations found were of a level that could be inhibitory to PCR in relation to the microsatellite techniques used in this study. From the work conducted in both Chapters 4 and 5 a troubleshooting protocol adapted for use in L. decolor was developed and implemented to determine the endogenous and exogenous parameters responsible for the function and reproducibility of PCR of microsatellite loci in L. decolor. In Chapter 6, the novel microsatellites isolated from L. decolor in Chapter 4 were used to investigate genetic structure and gene flow from Australian and international L. decolor populations. In Chapter 6 the first evidence of population differentiation, gene flow and dispersal in invasive populations of L. decolor was found. In addition, the eleven microsatellites isolated from L. decolor were cross-amplified in five other important Liposcelis pests, L. bostrychophila, L. entomophila, L. paeta, L. rufa, and L. corrodens, from which informative population genetic studies are now possible. Finally, Chapter 7 comprises the thesis synopsis, implications and future research.

Les invasions biologiques sont un fardeau économique important si elles affectent des ressources critiques pour l'alimentation, la sante humaine ou les productions agricoles. Les ravageurs de la pomme de terre sont un challenge économique important tant ce tubercule est un aliment clé dans les pays andins. Il est possible de suivre la dispersion récente de la teigne du Guatemala, T. solanivora en Amérique du Sud depuis son introduction au Vénézuela à sa propagation progressive vers le sud. Par ailleurs, les invasions récentes fournissent un modèle unique pour analyser les processus d'adaptation de tout l'écosystème receveur au nouveau venu. Cette introduction de T. solanivora et sa coexistence avec la teigne endémique Phthorimaea operculella, nous offre la possibilité d'étudier l'adaptation de populations virales inféodées à P. operculella au nouvel hôte T. solanivora. Une étude de terrain a été engagée dans les régions productrices de pomme de terre en Colombie. A partir des larves de T. solanivora collectées sur 5 sites distincts, des infections à granulovirus ont été détectées. Tous les isolats viraux sont apparentés au Phthorimaea operculella granulovirus (PhopGV) précédemment décrit. Des différences de pathogénicité envers les deux hôtes ont été observées. Une variabilité a été détectée pour certains isolats au niveau de deux marqueurs génétiques. Les populations présentant une diversité génétique s'avèrent plus pathogènes sur les deux hôtes que des populations génétiquement homogènes. Elles offrent une opportunité pour le contrôle biologique de ces ravageurs. Des populations artificielles ont été construites pour mimer des populations naturelles mélangées. Elles se comportent de la même manière d'un point de vue biologique, mais l'évolution de la fréquence des marqueurs n'est pas liée à l'efficacité biologique, ce qui suggère que des différences non détectées dans le génome pourraient être responsables de l'adaptation de l'hôte. La productivité des infections dans les deux hôtes a été étudiée car elle est la clé de voute du développement d'un agent de contrôle biologique. Les productivités sur P. operculella (1,36 à 2,69 × 108 OBs/ mg) et T. solanivora (0,48 à 3,64 × 108 OBs/mg) ne sont pas très différentes. Les populations génétiquement mélangées ne se distinguent pas des populations homogènes par leur production totale dans l'un ou l'autre des deux hôtes, cependant, les rendements (production virale/inoculum) montrent des différences claires, les populations mélangées (naturelles ou artificielles) sont plus performantes sur les deux hôtes. Aucune réduction de la pathogénicité sur l'hôte d'origine n'a été observée après plusieurs cycles de réplication de la population virale sur l'hôte alternatif. Les populations virales originellement adaptées à P. operculella ont évolué pour infecter T. solanivora. Dans les régions où les deux hôtes sont présents, les populations virales développent une stratégie pour être efficaces sur les deux hôtes.

Title from title page of PDF (University of Missouri--St. Louis, viewed March 10, 2010). Includes bibliographical references (p. 26-31).

No description available.

Ecosystems across the globe are facing a range of anthropogenically-driven changes, including biotic invasions, urbanisation and land-use alterations, which can affect ecosystem structure and stability. To manage both native species decline and invasive species spread it is imperative that we can accurately predict how current global environmental change will affect biotic communities. I examined effects of different land uses at both landscape- and habitat-scales on native (Culex pervigilans) and exotic (Aedes notoscriptus) mosquito distributions in lentic (standing water) freshwater habitats. Because of the importance of land use on habitat characteristics, I expected different land uses would contain different biotic communities, and that mosquitoes would more likely be present in simple communities with fewer predators. Moreover, because habitat disturbance and modification can significantly influence community structure, I expected less diverse pond communities in habitats within highly modified urban and pasture land uses would also be more likely to contain mosquitoes. I found land use affects mosquito presence, and was likely strongly linked with land-use effects on predator presence and taxon richness. Predators were more common in habitats within native forest and tussock grassland, and mosquitoes were almost entirely restricted to urban and pasture habitats. Moreover, local habitat characteristics had a strong influence on both mosquito and predator presence, with deeper and more open habitats supporting greater predator abundance, thereby excluding mosquito larvae. To further investigate the global of climate change on predator-prey interactions involving Ae. notoscriptus and Cx. pervigilans, I conducted two experiments. Firstly, I measured effects of habitat warming and short- and long-term habitat drying on interactions between the two mosquito species and three predatory invertebrates, Anisops wakefieldi backswimmers, Austrolestes colensonis damselflies, and Procordulia smithii dragonflies, which represented predators characteristic of different habitat drying regimes. A second experiment further tested interactions between A. wakefieldi and the two mosquito species in a wider range of temperatures. There was little evidence that short-term habitat drying affected interaction strengths of any of the predator-prey combinations, but strong evidence for the importance of temperature-mediated predation rates which depended on both predator and prey identities. Here, predators characteristic of more temporary hydroperiods showed temperature-mediated predation responses on the two mosquito species: increasing temperature resulted in greater predation on native Cx. pervigilans but not effect on predation on exotic Ae. notoscriptus. The second experiment revealed, again, that predation depended on both temperature and mosquito species with higher predation occurring at increased temperature, but also indicated life history traits could mediate the overall effect of temperature-mediated predation. Overall, I have shown that interactions between temperature, predator identity and mosquito species will be very important in determining the potential for mosquitoes to invade under a changing climate. Considering effects of both climate change and land-use-driven habitat modification on the invasion potential of mosquitoes in freshwater communities will therefore be important for managing both native species decline and spread of invaders. Moreover, research and management decisions on critical species like mosquitoes will need to encompass multiple drivers of climate change at both global and local scales.

No description available.

According to Baker (1955), success of plant invasions can be attributed to autogamous breeding systems and generalist pollination systems. A test of Baker's rule was carried out on 19 invasive alien plant species in KwaZulu-Natal, South Africa. Natural levels of fruit set in these plants was high (median= 71.5% fruit set per plant). Breeding system experiments for 18 species showed that 17% of the species are allogamous, 72 % are autogamous and 11% are apomictic. This contrasts markedly with a general flora of 1472 species in which 65% are allogamous, only 14% are autogamous, and 21% are apomictic. Because the breeding systems of the alien species were largely autogamous, pollinators make only a small contribution to the overall reproductive success. Seventy one percent of the 14 alien species for which pollinators were obtained were pollinated by honeybees, which are super-generalists and ubiquitous in a generalist pollination systems. However, some species showed pre-adaptation to relatively specialized pollination systems, involving hawkmoths, butterflies and Xylocopa bees respectively. Thus, alien plants were not visited by a wide range of insects, but rather showed pre-adaption to one or more pre-existing guilds in the new habitat. Pollen limitation experiments showed no evidence that reproductive success in populations of the species is limited by pollen availability. / Thesis (M.Sc.)-University of Natal, Pietermaritzburg, 2001.

The recent and rapid expansion of Phragmites australis in North America provides an opportunity to relate dispersal patterns to landscape structure. Linear wetlands, such as roadside or agricultural ditches, may serve as corridors that facilitate dispersal at the landscape scale, but there is little quantitative information on patterns of invasion in these habitats. Remote sensing data, GIS, and field observations were used (1) to assess the feasibility of mapping populations of P. australis in linear wetlands and (2) to quantify and explain recent invasion patterns of P. australis in two periurban areas of southern Quebec. An accuracy assessment demonstrated the reliability of aerial photographs to map populations in linear habitats. The intrinsic growth rate observed is high compared to those reported in natural wetlands. Spatial analysis revealed that colonization events are not constrained by the network's configuration. Logistic regressions confirmed the effect of road corridors on the spread of P. australis.

Ever since Korea and Japan established kingdoms in the 6th century, both countries greatly influenced each other politically, militarily, socially, culturally, and economically through international exchange. Korea and Japan kept their close relationship throughout history because of geographic proximity. It is also notable that 54 per cent of Japanese males and 66 per cent of Japanese females carry Sino-Korean genes in present-days and there are records that Japan carried a close relationship with Paekche, a kingdom of the Korean peninsula which introduced script, Confucianism, and Buddhism to Japan at an early stage. In the Medieval Period, Korea and Japan maintained a friendly trade policy but there were incidents such as Mongol invasions, wakō (Japanese pirates) raids and two invasions by Toyotomi Hideyoshi, which worsened the relations between the two countries. And yet, during Japan’s period of isolation (from 1639 to1854), Korea was the only nation with which full and free trade was permitted. The 20th century is based on invasion and colonisation of Japan over Korea. For 35 years from 1910 to 1945, under the control of Japan, the Japan-Korea relationship was nothing but misfortune: forced labour, suppression of Korean culture and language, press-gangs, sex slaves, and so forth. The aim in this thesis is to go into greater detail about each significant event and its effect on the relationship between Japan and Korea to uncover some rationale or pattern such as gekokujō (the master being outdone by the pupil, and being treated thereafter with contempt).