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.
| Identifer | oai:union.ndltd.org:ADTP/219554 |
| Date | January 2006 |
| Creators | Mikac, Katarina Maryann, n/a |
| Publisher | University of Canberra. Institute of Applied Ecology |
| Source Sets | Australiasian Digital Theses Program |
| Language | English |
| Detected Language | English |
| Rights | ), Copyright Katarina Maryann Mikac |
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