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.
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:sun/oai:scholar.sun.ac.za:10019.1/17979 |
| Date | 12 1900 |
| Creators | Vorster, Carlien |
| Contributors | McGeoch, Melodie A., Prozesky, Heidi E., Stellenbosch University. Faculty of AgriSciences. Dept. of Conservation Ecology and Entomology. |
| Publisher | Stellenbosch : Stellenbosch University |
| Source Sets | South African National ETD Portal |
| Language | en_ZA |
| Detected Language | Unknown |
| Type | Thesis |
| Format | 196 p. : ill., maps |
| Rights | Stellenbosch University |
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