Thesis (MSc)--Stellenbosch University, 2011. / ENGLISH ABSTRACT: Since its introduction in 1898 into South Africa, the Argentine ant, Linepithema humile [Mayr 1868 (Hymenoptera: Formicidae)], has invaded human-occupied areas (i.e. urban and agricultural areas) and natural areas characterised by few, if any, anthropogenic disturbances. However, compared to other countries in which the Argentine ant has been recorded, and until the past few decades, very little research had been done on this invasive ant in South Africa. Consequently, several issues concerning its ecological and social effects are still under-researched. The first of these issues concerns the lack of knowledge about the distribution of the Argentine ant in the natural areas, particularly the protected areas (PAs), of South Africa. In order to determine how many PAs are occupied by this invasive ant, a study was conducted in the Western Cape Province (WCP). It was found that, of the 614 PAs documented for WCP, ten have a known presence and nine known absence records of the Argentine ant. The remainder of the PAs have no known occupancy records for this ant. A second issue concerns the seasonal bait preference of the Argentine ant in a fynbos habitat. Six bait treatments (two carbohydrate and protein baits, a mixture of the carbohydrate and protein treatments, and a control) were applied in a fynbos habitat across a sampling grid in four different Latin Square designs, i.e. once for every season. Based on these experiments, it was determined that the Argentine ant prefers the mixture of carbohydrate and protein treatments, and that this preference does not change according to season. Furthermore, previous studies conducted in Jonkershoek Nature Reserve [JNR (in WCP)] determined the existence of a distribution boundary of Argentine ants in an area known as Swartboschkloof. Therefore, the third issue concerned the exact location of the distribution boundary and possible reasons for its establishment. This distribution boundary of the Argentine ant was found to be present 450 m from Swartboschkloof hiking trail. A combination of several explanatory variables may contribute to the maintenance of this boundary, i.e. a change in the horizontal and vertical vegetation distribution, as well as in the slope and aspect across the distribution boundary. With these explanatory variables, the increasing presence of an indigenous ant species, Anoplolepis custodiens, from this boundary may also have contributed to the distribution boundary. In addition, the short-term effect of a fire that swept through this area was also assessed, which revealed that Argentine ants are severely negatively affected by fire (at least over the short-term), i.e. their abundance decreased considerably after the fire and their local distribution range contracted. The final issue concerns the public perceptions of invasive alien species (IAS) in general and the Argentine ant specifically, at JNR. This study revealed that the majority of visitors to JNR were aware of the presence of IAS in South Africa and in its PAs, while very few visitors knew about the Argentine ant. This study also revealed that future research concerning South Africans perceptions of IAS might play a strong contributing role in conservation. / AFRIKAANSE OPSOMMING: Sedert die Argentynse mier, Linepithema humile [Mayr 1868 (Hymenoptera: Formicidae)], in 1898 in Suid-Afrika ingevoer is, het dié mier mens-bewoonde gebiede (soos stedelike en landbou gebiede) en natuurlike gebiede, gekenmerk deur min, indien enige, antropogeniese versteuringe, binnegedring. Nietemin, in vergelyking met ander lande waar die Argentynse mier opgeteken is, en tot die onlangse paar dekades, is min navorsing oor hierdie indringermier in Suid-Afrika onderneem. Gevolglik is daar verskeie kwessies rondom die mier se ekologiese en sosiale uitwerkinge wat nog nie nagevors is nie. Die eerste kwessie het betrekking op die gebrek aan kennis oor die Argentynse mier se verspreiding in die natuurlike gebiede, veral die beskermde gebiede (BG), van Suid-Afrika. Om te bepaal hoeveel BG deur hierdie indringermier beset word, is ʼn ondersoek in die Wes-Kaapprovinsie (WKP) uitgevoer. Daar is bevind dat, van die 614 BG gedokumenteerd in die WKP, het tien bevestigde aanwesigheid- en nege bevestigde afwesigheidrekords van hierdie mier. Die oorblywende BG het geen bekende besettingsrekords van hierdie mier nie. ʼn Tweede kwessie het betrekking op die seisoenale lokaasvoorkeur van die Argentynse mier in ʼn fynbos habitat. Ses lokaas-behandelings (twee koolhidraat en proteïen lokaas, ʼn mengsel van die koolhidraat en proteïen behandelings, en ʼn kontrole) is aangewend in ʼn fynbos habitat, oor ʼn steekproefruitgebied, in vier verskillende Latyns-kwadraatpatrone (“Latin Sqaure designs”), d.i. een vir elke seisoen. Op grond van hierdie eksperimente is vasgestel dat die Argentynse mier die mengsel van koolhidrate en proteïne verkies, en dat hierdie voorkeur nie seisoenaal verander nie. Boonop, vorige ondersoeke wat in die Jonkershoek Natuurreservaat [JNR (in die WKP)] uitgevoer is, het ʼn verspreidings-grens van Argentynse miere ontdek in ʼn gebied bekend as Swartboschkloof. Gevolglik het die derde kwessie betrekking op die presiese ligging van hierdie grens en moontlike redes waarom dit gevestig het. Dié verspreidings-grens van die Argentynse mier is 450 m vanaf die Swartboschkloof voetslaanpad gevind. ʼn Kombinasie van verskeie verklarende veranderlikes kon tot hierdie grens bygedra het, d.i. ʼn verandering in die horisontale en vertikale plantegroeiverspreiding, sowel as in die helling en ligging oor die verspreidings-grens van die Argentynse mier. Tesame met hierdie verklarende veranderlikes, kon die toenemende teenwoordigheid van ʼn inheemse mier, Anoplolepis custodiens, vanaf hierdie grens ook tot die verspredings-grens bygedra het. Daarbenewens is die korttermyn-effek van ʼn vuur wat deur die area beweeg het, ook bestudeer. Die ondersoek het getoon dat die Argentynse mier (ten minste oor die korttermyn) erg negatief deur vuur beïnvloed is, d.i. hul volopheid het ná die vuur aansienlik verminder en hul plaaslike verspreidings-grens het gekrimp. Die finale kwessie het betrekking op openbare persepsie van uitheemse indringerspesies (UIS) oor die algemeen en spesifiek die Argentynse mier, by JNR. Hierdie ondersoek het aan die lig gebring dat die meerderheid van besoekers aan JNR bewus was van die teenwoordigheid van UIS in Suid-Afrika en in dié se BG, terwyl baie min egter van die Argentynse mier geweet het. Hierdie ondersoek het ook aan die lig gebring dat toekomstige navorsing rakende Suid-Afrikaners se persepsie van UIS ʼn sterk bydra tot bewaring kan maak.