Population genetic structure and abundance of two Ceratitis species (Tephritidae) of agricultural importance in South Africa
| dc.contributor.advisor | Addison, Pia | en_ZA |
| dc.contributor.advisor | Terblanche, J. S. | en_ZA |
| dc.contributor.advisor | Jansen van Vuuren, Bettine | en_ZA |
| dc.contributor.author | Karsten, Minette | en_ZA |
| dc.contributor.other | Stellenbosch University. Faculty of AgriSciences. Dept. of Conservation Ecology and Entomology. | en_ZA |
| dc.date.accessioned | 2015-01-13T11:46:30Z | |
| dc.date.available | 2016-01-01T03:00:15Z | |
| dc.date.issued | 2014-12 | |
| dc.description | Thesis (PhD)--Stellenbosch University, 2014. | en_ZA |
| dc.description.abstract | ENGLISH ABSTRACT: Research in the field of biological invasions has increased dramatically in the last two decades, especially due to the impact of human activity such as, transport, travel and international trade. Different stages of invasion have been proposed, each stage posing different barriers that must be overcome by the organism for it to become established. For the prevention of new invasions and the formulation of a successful integrated pest management program (IPM), knowledge of natural species community assemblage, as well as movement patterns, temporal distribution and invasion pathways are critical. In this dissertation I make use of two agricultural important fruit fly species, Ceratitis capitata amd C. rosa, in the Tephritidae family in different stages of the invasion process using different research methods to (i) investigate seasonal variation in fruit fly abundance in orchards and natural vegetation in the Western Cape to determine whether natural vegetation is used as possible refugia; (ii) to investigate maccrogeographic population structure of C. capitata with a focus on southern Africa to reconstruct and test C. capitata’s invasion pathway using a Bayesian framework; (iii) to investigate the population genetic structure, using molecular and morphological markers, to estimate gene flow and dispersal ability of C. rosa in South Africa. Results showed that C. capitata was the most abundant species captured and Biolure® the most effective lure. The largest number of individuals of either species (C. rosa and C. capitata) were captured in austral autumn (March-May) in both orchards and natural habitat with low capture rates throughout the rest of the year. Orchards and natural habitats were significantly different with higher trap catches always found in orchards. Based on microsatellite markers, C. capitata showed a decrease in genetic diversity moving away from the native range (Africa) into the introduced range (Australia, Greece, Guatemala, Madeira). Moreover, there was a clear pattern of differentiation between the African continent and the rest of the world indicating low levels of genetic connectivity. High connectivity throughout the African continent is problematic as this suggests that new invasions will move and colonize new areas unimpeded after first introduction. Lastly, my results indicate that there is no population structure in C. rosa within South Africa. This indicates that there are high levels of connectivity between different pest-occupied sites within the country and suggests that area-wide pest management should be undertaken on a much larger, preferably country-wide, scale. My results are discussed in the framework of invasion biology as well as integrated pest management. In conclusion, when investigating biological invasions, information from organismal biology and ecology as well as molecular biology can be valuable to inform decision-making regarding prevention and mitigation of pest species. | en_ZA |
| dc.description.abstract | AFRIKAANSE OPSOMMING: Navorsing op die gebied van indringer biologie het in die laaste twee dekades dramaties toegeneem, veral ten opsigte van die impak van menslike aktiwiteite soos vervoer, reis en internasionale handel op nuwe kolonisasies. Verskillende fases is voorgestel as deel van die indringingsproses en vir ‘n spesie om suksesvol te kan vestig moet die organisme die verskillende hindernisse in elke fase oorkom. Kennis van die natuurlike samestelling van spesies-gemeenskappe, spesie bewegingspatrone, temporele verspreiding en roetes van indringing is van kritieke belang vir die voorkoming van nuwe indringers sowel as die formulering van 'n suksesvolle geïntegreerde plaagbeheerprogram (GPB). In hierdie verhandeling pas ek verskillende navorsingsmetodes toe op twee vrugtevlieg spesies, Ceratitis capitata en C. rosa, van belang vir die landbou, in die Tephritidae familie in verskillende stadiums van die indringingsproses om (i) die seisoenale variasie in vrugtevlieg getalle vas te stel in vrugteboorde en natuurlike habitate in die Wes-Kaap en om te bepaal of die natuurlike habitat gebruik word as refugia; (ii) die wêreldwye bevolking genetiese struktuur van Ceratitis capitata te ondersoek met ‘n fokus op suidelike Afrika sowel as die indringing te rekonstrueer en te toets deur gebruik te maak van ‘n Bayesian raamwerk; (iii) die bevolking genetiese struktuur van Ceratitis rosa in Suid-Afrika te ondersoek met behulp van molekulêre en morfologiese merkers. Resultate het getoon dat C. capitata die mees algemene spesies was en dat Biolure® die mees doeltreffende lokmiddel was. Die grootste aantal individue van beide spesies (C. rosa en C. capitata) is gevang in die suidelike halfrond herfs (Maart-Mei) met lae vangste die res van die jaar. Boorde was beduidend anders as die natuurlike habitat, altyd met hoër vangste. Gebaseer op mikrosatelliet merkers het C. capitata 'n verlaging in genetiese diversiteit getoon vanaf die inheemse gebied (Afrika) na nuut gekolaniseerde gebiede (Australië, Griekeland, Guatemala, Madeira). Verder was daar 'n duidelike genetiese onderskeid tussen die Afrika-kontinent en die res van die wêreld. Die hoë vlak van verbinding op die Afrika-vasteland kan problematies wees omdat dit daarop dui dat nuwe besettings onbelemmerd na nuwe gebiede sal beweeg na die eerste kolonisasie. Laastens dui my resultate dat daar geen bevolking genetiese struktuur in C. rosa in Suid-Afrika is nie. Dit dui daarop dat daar verbindings is tussen verskillende plaag-besette lokaliteite in die land en dat area-wye plaag beheer op 'n veel groter, verkieslik landwye skaal onderneem moet word. Ek bespreek my resultate in die raamwerk van indringer biologie asook geïntegreerde plaagbeheer. Ten slotte, wanneer indringer biologie ondersoek word, is inligting met betrekking tot die organisme se biologie en ekologie sowel as molekulêre biologie van uiterse belang in die besluitnemingsproses om lig te werp op die voorkoming en beheer van peste. | af_ZA |
| dc.embargo.terms | 2015-12-31 | |
| dc.format.extent | 159 pages : illustrations | en_ZA |
| dc.identifier.uri | http://hdl.handle.net/10019.1/95744 | |
| dc.language.iso | en_ZA | en_ZA |
| dc.publisher | Stellenbosch : Stellenbosch University | en_ZA |
| dc.rights.holder | Stellenbosch University | en_ZA |
| dc.subject | Fruit-flies -- Genetics | en_ZA |
| dc.subject | Microsatellites | en_ZA |
| dc.subject | Agricultural pests -- Biological invasions | en_ZA |
| dc.subject | Fruit-flies -- Dispersal | en_ZA |
| dc.subject | UCTD | en_ZA |
| dc.title | Population genetic structure and abundance of two Ceratitis species (Tephritidae) of agricultural importance in South Africa | en_ZA |
| dc.type | Thesis | en_ZA |
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