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dc.contributor.authorVargas Mariana, L.en
dc.date.accessioned2009-05-20T04:06:56Z
dc.date.issued2006en
dc.identifier.urihttps://hdl.handle.net/10182/1072
dc.description.abstractThe effect of a free-living stage in host-parasite coevolution: a skink mite phylogenetic study in New Zealand. During the last decade, phylogenetic trees have even been used to compare ecologically related taxa such as parasites and their hosts, and are used to determine their level of coevolution or reciprocal adaptation in time. Diverse coevolutionary events have been detected for this ecological association, where generally the parasite has been regarded as one that feeds exclusively on the host and is likely to cospeciate with it. A different coevolutionary pattern might occur when the parasite has a free-living stage in its life cycle, in which the parasite may have the opportunity to abandon its host and successfully colonise a new species (host-switching) making cospeciation less likely. Many New Zealand skinks are infested with a parasitic mite, Odontacarus sp. (Prostigmata: Leeuwenhoekiidae), which becomes free-living as an adult. The genetic variation of these mites found on four hosts was analyzed for host- parasite coevolutionary events. The hosts were the McCann’s skink and the common skink in coastal Birdling Flat, Canterbury, plus these species and the Grand and Otago skinks in Macraes Flat, Central Otago, South Island, New Zealand. The genetic variation of fast evolving nuclear Internal Transcribed Spacers 2 and mitochondrial Cytochrome c Oxidase I in Odontacarus mites found on these hosts was determined by PCR and DNA sequencing and phylogenetic trees were built using the computer programs PAUP*4 and MrBayes 3. The results show that mite haplotypes only had a significant geographical division and no host-related differences. In Birdling Flat, the COI haplotypes were represented in two groups that infested both regional hosts and had 5.7 % divergence. The same individual mites belonged to a single ITS 2 haplotype, thus indicating a historical geographical division between two populations that now interbreed successfully. The Macraes Flat mites were divided into two COI haplotypes with 2.4% divergence and internal nodes, which showed greater genetic variability than the Birdling Flat populations. The Macraes Flat mites formed two ITS 2 haplotypes with 6% divergence. This greater geographical structure of the Otago mites is probably due to the older age of the mainland area compared to the recently exposed coastal locality of Birdling Flat. The COI haplotypes from the two different regions had a mean distance of 15.5%, with an earlier divergence time than that known for the hosts. For both genes, the haplotypes from different regions had 100% bootstrap support and the parasite showed no host specificity. Mites of the different COI and ITS haplotypes were found on most of the host species that were sampled in Canterbury and Otago. The results of this study suggest that a free-living stage in a parasite’s life cycle can favour coevolutionary events such as inertia (failure to speciate) and host-switching, probably as a result of resource-tracking of the parasite. NB: Electronic files contained on CD to accompany print copy are not included with this version of the thesis.en
dc.language.isoenen
dc.publisherLincoln Universityen
dc.subjectlizardsen
dc.subjectskinksen
dc.subjectbiogeographyen
dc.subjectco-evolutionen
dc.subjectco-phylogeniesen
dc.subjectCytochrome c Oxidase Ien
dc.subjectfree-livingen
dc.subjecthost-switchingen
dc.subjectinertiaen
dc.subjectInternal Transcribed Spacer 2en
dc.subjectmiteen
dc.subjectNew Zealanden
dc.subjectOdontacarusen
dc.subjectOligosomaen
dc.subjectparasiteen
dc.subjectphylogeneticen
dc.titleHost-parasite coevolution in New Zealand: how has Odontacarus, a mite with a free-living stage in its life-cycle, coevolved with its skink host?en
dc.typeThesis
thesis.degree.grantorLincoln Universityen
thesis.degree.levelMastersen
thesis.degree.nameMaster of Applied Scienceen
dc.subject.marsdenFields of Research::270000 Biological Sciences::270700 Ecology and Evolution::270706 Life histories (incl. population ecology)en
dc.subject.marsdenFields of Research::270000 Biological Sciences::270200 Genetics::270203 Population and ecological geneticsen
lu.contributor.unitLincoln Universityen
lu.contributor.unitFaculty of Agriculture and Life Sciencesen
lu.contributor.unitDepartment of Pest Management and Conservationen
dc.subject.anzsrc0603 Evolutionary Biologyen
dc.subject.anzsrc060307 Host-Parasite Interactionsen
dc.subject.anzsrc060302 Biogeography and Phylogeographyen
pubs.organisational-group/LU
pubs.organisational-group/LU/Agriculture and Life Sciences
pubs.organisational-group/LU/Agriculture and Life Sciences/ECOL
pubs.publication-statusPublisheden


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