Thesis (MSc)--Stellenbosch University, 2013. / ENGLISH ABSTRACT: The Afroedura nivaria complex is one of the six recognized species complexes within a southern African endemic genus, Afroedura. The A. nivaria complex is a morphologically conservative group of medium-sized geckos endemic to South Africa though they are unevenly distributed in the Eastern Cape, Free State and KwaZulu-Natal provinces. The complex comprises the following five species: A. nivaria (Boulenger 1894), A. amatolica (Hewitt 1925), A. karroica (Hewitt 1925), A. tembulica (Hewitt 1926) and A. halli (Hewitt 1935). These nocturnal and rupicolous geckos shelter in narrow rock crevices on outcrops. It is currently unknown whether a) the described species are valid and b) if additional lineages are present on isolated outcrops. I investigated the hypothesis that endemics with a narrow distribution, that is, A. amatolica and A. tembulica are valid species but that isolated populations in the widespread species (A. nivaria, A. karroica and A. halli) demonstrate genetic variation at the species level. Fragments of two mitochondrial genes (16S rRNA and ND4) and a single nuclear marker (KIAA) were sequenced and analysed using Bayesian inference, maximum parsimony and maximum likelihood. All analyses strongly supported the genetic distinctiveness of the described species. The A. nivaria complex is not monophyletic, A. karroica appeared to be outside the species complex and A. pondolia (thought to be outside the A. nivaria complex) consistently nested within A. nivaria complex. Additional clades recovered in the phylogeny within A. halli and A. nivaria had large genetic divergences and no spatial overlap. Narrowly distributed A. amatolica showed to have two highly diverged clades. Clades recovered in the phylogeny highlight geographical structuring. These findings suggest the existence of up to four additional cryptic lineages within the complex. I used morphometric data (ecologically relevant morphological traits) to investigate whether the genetic lineages would present morphological conservatism. Multivariate analyses of 19 variables showed variation within the A. nivaria species complex was accounted for mostly by differences in locomotor apparatus (limbs and feet) and head dimensions. These traits are mostly related to microhabitat usage and/or dietary specialization in lizards. There were no significant differences for body dimensions between species within the complex, indicative of morphological conservatism. It appears genetic divergence has been achieved among the different clades within A. nivaria complex, but with much similarity in phenotype being retained because of fragmented but similar habitats occupied. / AFRIKAANSE OPSOMMING: Die Afroedura nivaria kompleks is een van ses herkende spesies komplekse binne die endemiese suidelike Afrika genus, Afroedura. Die A. nivaria kompleks is ‘n morfologiese konserwatiewe groep bestaande uit medium grootte geitjies endemies tot Suid Afrika, alhoewel hulle oneweredig verspreid is in die Oos Kaap, Vrystaat en Kwazulu-Natal provinsies. Die kompleks bestaan uit die volgende vyf spesies: A. nivaria (Boulenger 1894), A. amatolica (Hewitt 1925), A. karroica (Hewitt 1925), A. tembulica (Hewitt 1926) and A. halli (Hewitt 1935). Hierdie geitjies kom snags voor en skuil tussen nou skeure op klip koppies. Dit is tans onbekend of a) die beskryfde spesies geldig is en b) of die addisionele afstammelinge voorkom op geisoleerde koppies. Met die studie het ek die hipotese ondersoek dat endemiese spesies met ‘n noue verspreiding (A. amatolica en A. tembulica) geldige spesies is, maar dat spesies met ‘n wye verspreiding (A. nivaria, A. karroica and A. halli) genetiese variasie op spesie vlak wys. Fragmente van twee mitochondriale gene (16S rRNA and ND4) en ‘n enkele nuklêre merker (KIAA) se basispaaropeenvolgingsdata was verkry en geanaliseer deur Bayesian inferensie, maksimum parsimonie en maksimum waarskynlikheid. Alle analise het die genetiese kenmerkendheid van die beskryfde spesies sterk ondersteun. Die A. nivaria kompleks is monofileties, A. karroica het geblyk om buite die spesies kompleks voor te kom en A. pondolia (voorheen beskryf as buite die A. nivaria kompleks) het voortdurend binne die A. nivaria kompleks voorgekom. Addisionele klades afkomstig vanaf die filogenië van A. halli en A. nivaria het vir beide spesies groot genetiese divergensie met geen ruimtelike oorvleuling gewys. Afroedura amatolica, met sy noue verspreiding, het twee hoogs divergente klades getoon. Die klades onthul deur die filogenie beklemtoon ‘n geografiese struktuur. Hierdie bevindings blyk die bestaan van tot vier ekstra kriptiese afstammelinge binne die kompleks. Ek het morfometriese data (ekologiese relevante morfologiese eienskappe) gebruik om vas te stel of die genetiese afstammelinge morphologies konserwatief sal wees. Meerveranderlike analises op 19 veranderlikes het variasie binne die A. nivaria spesies kompleks getoon. Hierdie veranderinge was meestal gevind in die beweeglikheidsapparatuur (ledemate en voete) en kop dimensies. Die verskeie eienskappe hou meestal verband met die mikrohabitatte wat gebruik word en/of dieët spesialisering in akkedisse. Daar was geen noemenswaardige verskille in liggaamsdimensies tussen spesies in die kompleks nie, beduidend op ‘n konserwatiewe morfologie. Dit wil blyk of genetiese divergensie tussen die verskeie klades van die A. nivaria kompleks bewerkstellig is met ooreenstemming in die fenotipes as gevolg van gefragmenteerde maar soortgelyke habitat verbruik.

Thesis (MSc)--Stellenbosch University, 2013. / ENGLISH ABSTRACT: The objectives of this research were to: (1) accurately identify chromosome homology, (2) identify chromosome rearrangements leading to diploid number variation and chromosome evolution to formulate the ancestral gerbil karyotype and distinguish homoplasy from hemiplasy, and (3) construct a phylogeny using chromosomal characters based on G-banding and fluorescence in situ hybridization (FISH) of ten gerbil species representing five genera (Gerbilliscus, Desmodillus, Psammomys, Meriones, Taterillus), with probes derived from flow-sorted chromosomes of G. paeba (GPA, 2n = 36), and polarised with the murid outgroup, Micaelamys namaquensis. All paints successfully hybridized to all ingroup and outgroup taxa. Three of the 19 G. paeba painting probes (GPA 7, 9 and X [including the X; autosome translocation in T. pygargus]) were conserved as whole chromosomes, and 16 were rearranged (GPA 1-6, 8, 10-17). Chromosome painting correctly identified the homology of the heterochromatic GPA 7, which was conserved as whole chromosomes in all gerbils. Thirteen previously misidentified G-band homologies were correctly identified with FISH; one in D. auricularis, and six each in G. kempi and G. gambianus. Homology maps identified 57 syntenic associations and that 19 rearrangements are responsible for diploid number differentiation among species. Parsimony analysis of the two matrices (syntenic association and rearrangements) retrieved a sister-species relationship between G. gambianus and G. kempi, and P. obesus and M. persicus (syntenic associations), an unresolved clade that included D. auricularis, G. gambianus, P. obesus and M. persicus (chromosome rearrangements) and a basal position for T. pygargus. Phylogenies derived from chromosomal data failed to resolve the deeper nodes. Consequently, characters were subsequently mapped on a molecular consensus tree (including a chronogram). This allowed inferences on the rate of chromosome evolution, which indicates that the basal D. auricularis is separated from Gerbilliscus by nine rearrangements (four Robertsonian fusions, five inversions), at a rate of 1.25/Myr. Gerbilliscus species evolved with an average of 10 Robertsonian rearrangements involving GPA 1–6, 8, 10 – 12, of which four are homoplasies (GPA 1-3, 5), one a potential hemiplasy (GPA 5) to southern African taxa, one a synapomorphy to G. paeba and G. tytonis (GPA 6), two synapomorphies in G. kempi and G. gambianus (GPA 11, 12), and three are synapomorphic to Gerbilliscus (GPA 4, 8, 10). Homoplasic characters across the two clades include GPA 3 (T. pygargus, G. paeba and G. tytonis) and GPA 5p-q prox (D. auricularis, P. obesus and M. persicus). Gerbilliscus (excluding G. paeba and G. tytonis) had the slowest chromosome evolutionary rate of < 1/Myr; G. paeba and G. tytonis were slightly faster at 2/Myr. The clade comprised of M. persicus, P. obesus and T. pygargus evolved faster, at a rate of 4/Myr (seven fissions, five fusions, two inversions), 2.3/Myr (seven fissions, two fusions, four inversions) and 16/Myr (eight fusions), respectively, indicating heterogeneity among Gerbillinae: A slow rate in Desmodillus and Gerbilliscus, and a fast evolutionary rate in Psammomys, Meriones and Taterillus. The putative ancestral karyotype was postulated to be 2n = 56, and included five biarmed autosomes and X chromosome, and 22 acrocentrics. This is provisional, since Brachiones, Desmodilliscus, Pachyuromys, Sekeetamys, Gerbillus and Rhombomys were not analysed. / AFRIKAANSE OPSOMMING: Die objektief van hierdie navorsing was om: (1) akkurate chromosoom homologie te identifiseer, (2) chromosoom herranskikkings te identifiseer wat mag lei tot diploide chromosoom getal variasie en chromosoom evolusie ten einde te formuleer die voorouer karyotiepe van “gerbils” sowel as om te onderskei tussen homoplasie en hemiplasie, en (3) die konstruksie van 'n filogenetiese boomstam gebasseer op chromosoom karakters verkry vanaf G-banding en FISH (fluoressensie in situ hibridisasie) van tien “gerbil” spesies wat vyf genera verteenwoordig (Gerbilliscus, Desmodillus, Psammomys, Meriones, Taterillus), deur van geskikte sondes gebruik te maak wat verkry in deur floei-sorteerde chromosome van G. peaba (GPA, 2n = 36), wat gepolariseerd was met die Murid buitegroep, Micealamys namaquensis. Alle chromosoom verwe het suksesvolgehibridiseer aan al die ingroep en buitegroep taxa. Drie van die 19 G.peaba verfwe (GPA 7, 9 and X (including the X; autosome translocation in T. pygargus) was bewaar as heel chromosome, en 16 herrangskik (GPA 1-6, 8, 10-17). Chromosoom verfwing kon suksesvol die homologie van die heterochromatise GPA7 identifiseer wat gekonserveerd was as heel chromosome in al die “gerbils”, wat moontlik aandui die teenwoordigheid van funksionele gene. Dertien voorheen mis geidentifiseerde G-band homologieë was gekorregeer deurmiddel van FISH, een in D. auricularis, en ses elk in G. kempi en G. gambianus. Homologie kaarte het 57 sintesiese assosiasies geidentifiseer en dat 19 herrangskikings verantwoordelik was vir diploied nommer differensiasies tussen spesies. Parsimonie analises van die twee matrikse (sinteniese assosiasies en herrangskikings) wys 'n suster-spesie verwantskap tussen G. gambianus en G. kempi, en P. obesus en M .persicus (sinteniese assosiasies), 'n unopgeloste klade wat D. auricularis, G. gambianus, P. obesus en M. persicus (chromosoom herrangskikkings) opmaak vorm die basale posisie vir Taterillus pygargus. Filogenetise boomstamme verkry vanaf die chromosomale data misluk egter om die dieper nodes op te los. Karakters was daarna geplot op 'n konsensus boom (insluitend 'n chronogram). Dit het dieper insigte toegelaat soos die tempo van chromosoom evolusie, wat aandui dat die basale D. auricularis geskei is vanaf Gerbilliscus met nege herrangskikkings (vier Robertsonian, vyf inversies) teen 'n tempo van 1.25/Mja. Gerbilliscus spesies het verander met 13 herranskikinge (11 saamsmeltings en twee inversies), waarvan vier potensiele homoplasies/hemiplasies (GPA 1-3, 5). Met die uitsluitsel van G. paeba en G. tytonis, het Gerbilliscus die laagste chromosoom evolutionêre tempo van al die “gerbils” < 1 /Mja, G. paeba en G. tytonis was ietwat vinniger met 'n tempo van 2/Mja. The klade wat bestaan uit M. persicus, P. obesus en T. pygargus verander vinniger as Desmodillus en Gerbilliscus, met 'n evolutionêre tempo van 4/Mja (sewe fissies, vyf samesmeltings, twee inversies) en 2.3 Mja (sewe fissies, twee samesmeltings, vier inversies) onderskeidelik, wat grootendeels tandem was. Die karyotiepe van Taterillus pygarus het agt samesmeltings gehad wat predominant tandem was, teen 'n tempo van 16/Mja. Terwyl meeste van die herrangskikinge synapomorfies was, was sommige homoplasties of hemiplasties. Homoplastiese karakters wat gedeel was tussen die twee klades sluit in GPA 3 (in T pygargus en G. paeba en G. tytonis) en GPA 5p-q prox (D. auricularis, P. obesus en M. persicus). GPA 5 was hemiplasties aan alle suider Afrikaanse taxa. Die analise van sinteniese assosiasies en chromosoom herrangskikings was geanaliseer in PAUP, en gepolariseer met die murid Micealamys namaquensis. Taterillus pygarus het 'n basale posisie in beide filogenetiese boomstamme. Die data stel voor dat FISH meer akkurate resultate lewer op chromosoom homologie as die streng gebruik making van banding patrone. Verder het die tempo van chromosoom evolusie gevarieër vanaf stadig (Desmodillus en Gerbilliscus) tot vinnig (Psammomys, Meriones en Taterillus), chromosoom karakters egter was nie sterk genoeg om dieper filogenetiese verwantskappe te ondersoek nie. Die voornemende voorouerlike karytiepe van “gerbils” was hier gehipotiseer as 2n = 56. Drie bevindinge resoneer uit hierdie studie. Eerstens, chromosoom verwing kon chromosoom homologieë wat voorheen deur banding studies mis ge-identifiseer was korrek identifiseer: hierdie sluit in een konflik in D. auricularis, en ses elk vir G. kempi en G. gambianus. Tweedens, die homologie van die heterochromatiese of C-positiewe autosome, GPA 7, was gedemonstreer as bewaar as 'n heel chromosoom as beide heterochromaties en euchromatiese chromosome in alle “gerbils”, wat aandui dat dit functionele gene dra. Derdens gebasseer op simpleisiomorfe wat geidentifiseer was vanaf die homologie kaarte en vergelykbare opleidings, hipotiseer ek dat die voorgestelde voorouer karyotiepe bestaan uit ses autosome (GPA 7, 9, 13, 15, 16, 17) en die X chromosoom, wat onveranderd gebly het tussen alle suider Afrikaanse taxa. Met die uitsluitsel van GPA 7p/7q, was almal behoue as twee-armige chromosome in die voor ouer karyotiepe. In lyn met hierdie is, 21 akrosentries GPA1p,1q, 2p, 2q, 3p, 3q, 4p, 4q, 5p, 5q, 6p, 6q, 8p, 8q, 10q, 10p, 11p,11q, 12p, 12q en 14, wat lei tot die voorgestelde voor ouerlike diploiede chromosoom getal van 2n = 56. Diè karyotiepe word voorgestel as 'n werkende hipotese deels omdat Brachiones, Desmodilliscus, Pachyuromys, Sekeetamys, Gerbillus en Rhombomys nie geanaliseer was nie, en dat die idiale buite groep vir “gerbils” van die Acomyinae nie gebruik was om die karakters te polariseer was nie.

Thesis (MSc)--Stellenbosch University, 2013. / Ants emerged during the Cretaceous Period more than 100 million years ago (Grimaldi & Engel 2005; Perrichot et al. 2008) and diversified independently on different landmasses following the Early Cretaceous fragmentation of Pangaea (Grimaldi & Agosti 2000). Today, ants represent one of the most ecologically successful groups globally (Wilson 1987), and their diversity far exceeds that of other social insects (Hölldobler & Wilson 1990). Currently 21 subfamilies, 305 genera and 12465 recorded ant species exist (Bolton 2012). Ants occur in almost all terrestrial habitats (Brown 2000) and are not uniformly distributed across regions, biomes and continents. As with all other taxa, historical abiotic factors have played a major role in their diversification and biogeographic structure (Tolley et al. 2006), including climatic changes (Holldobler & Wilson 1990) and the necessity to adapt to new environmental conditions (Tolley et al. 2006). Many global areas still lack data on regional biodiversity and the historical processes that may have shaped it. This is particularly so for southern Africa where the ant fauna is still relatively poorly known (Robertson 2000) and where there have been no published biogeographic analyses for any ant taxon. There is a highly endemic ant fauna that has evolved in the dry regions of southern Africa, which shows unique adaptations to the extreme thermal niches of these regions. For example, ants in the genus Ocymyrmex have adapted to forage on barren ground at temperatures as high as 67 ºC, when most insects and other arthropods are unable to survive (Marsh 1985). Ocymyrmex have long legs and usually hold the head, thorax and gaster high above the substrate, which helps with body temperature regulation. These ants are most active at the hottest time of the day and they move very rapidly. For example, O. barbiger has been observed running at speeds of 23 m/min (Marsh, 1985). In some ant species such extreme temperatures may limit foraging activity (Ward, 2007) but, in the case of Ocymyrmex, adaptations to this extreme thermal niche allowed exploitation of resources (dead and heat stressed arthropods). Moreover, these ants have subterranean nests that are ideal to escape environmental extremes and to move their brood deeply under the ground (Marsh, 1985). The distribution of some ant taxa in these dry regions closely reflects borders between particular biomes. For instance, in South Africa the ponerine ant, Pachycondyla hottentota, and the sugar ant, Camponotus storeatus, follow the borders of the Nama and Succulent Karoo biomes respectively (Robertson 2000). In the light of this background the overall objective of this study is to revise the taxonomy and determine the historical drivers of diversification in an important group of arid-adapted ants, the Tetramorium solidum-group, which is mainly restricted to dry semi-desert areas in southern Africa. Members of the Tetramorium solidum-group are commonly encountered seed harvesters yet despite their apparent ecological importance, their taxonomy and biogeography remains largely unresolved. Thirty years elapsed since the last revision of the group by Bolton (1980) and since, ant surveys have considerably expanded the material available for study and provide an opportunity for a fresh perspective on this group. The specific aims of this project were twofold: 1) to revise the species of the Tetramorium solidum-group; and 2) to explore the phylogenetic relationships among members of the group and the bioclimatic factors restricting their current distributional ranges in southern Africa. My study is timely, as to date no attempt has been made to unravel the history of arid-adapted ant diversification in southern Africa. Such information is much needed for identifying areas of high species diversity and endemism (Azuma et al. 2006) and prioritizing areas for conservation (Faith 1992). The thesis consists of three chapters. In chapter one I use morphological characters to review the current taxonomy of the Tetramorium solidum-group. From these data I have compiled an updated identification key for the group and described five new species. In chapter two I have constructed a fossil-calibrated dated phylogeny for Tetramorium solidum-group species in order to explore the historical processes that may have contributed in structuring the current distribution patterns and endemism within and among the species of the group. In this chapter I also explore bioclimatic factors that may restrict the current distribution of members on the Tetramorium solidum-group, using correlative bioclimatic modeling approaches. Chapter three provides a brief and overall conclusion to the study. / Financial support from NRF

Thesis (MSc)--Stellenbosch University, 2013. / ENGLISH ABSTRACT: Limited dispersal, territoriality and the occupation of patchy habitats; characters that typify most African rock-dwelling (saxicolous or rupicolous) species, often result in structured genetic patterns with little or no gene-flow among populations (e.g., velvet worms, net-winged midges, elephant shrews, red rock rabbits and a variety of lizards and agamas). In an attempt to deepen our understanding of taxa that inhabit these “terrestrial islands” the distribution of genetic variation was studied at several spatial scales in the rock hyrax, Procavia capensis. This species has a polygynous social system that is unusual among taxa with similar ecological requirements, and a morphology that would intuitively be associated with poor dispersal capabilities (short limbs and a squat, heavy body). Possibly as a consequence of these considerations, few studies have attempted to determine the distance of migration by rock hyraxes and the influence that their social system and the surrounding landscape has on dispersal success. This investigation therefore tests hypotheses of how the ecology, distribution, social structure and the connectivity of the surrounding landscape have contributed to shaping the structure of rock hyrax genetic variation across the Namaqualand and western Fynbos regions. To do so, mitochondrial and microsatellite markers were used to document gene-flow at a fine spatial scale (an isolated population comprising 5 koppies), an intermediate spatial scale (across known geographic barriers to saxicolous taxa - the Cape Flats and Knersvlakte), and a regional spatial scale (across the Namaqualand/western Fynbos regions of South Africa - regions exhibiting contrasting landscape connectivity). In addition the genetic diversity, spatial clustering, sex-biased dispersal and relatedness (fine-scale) of colonies is described and the major genetic breaks detected in the investigation dated using a relaxed molecular clock approach. Finally, these results were compared to other studies that identified the Cape Flats and Knersvlakte as phylogeographic disruptors. The genetic patterns at a fine spatial scale were complex: Gene-flow was restricted by the social structure of the rock hyrax rather than geographic distance, dispersal was female-biased and there was significant genetic structure. Genetic structure was also evident at the intermediate and regional spatial scales. In the Hottentots Holland Mountains and Cape Peninsula gene-flow was restricted (in both data sets) in comparison to localities that traversed the Cape Flats. In contrast, gene-flow across the Knersvlakte was restricted in the mitochondrial DNA data set but not so with microsatellites. A similar pattern was observed at a regional scale pointing to male-biased dispersal within this species - a result of its polygynous social structure. In addition to sex-biased dispersal, landscape connectivity also influenced gene-flow on a regional spatial scale as the Namaqualand region, which has greater intermediate suitable habitat compared to the western Fynbos region, displayed significantly higher levels of gene-flow between sampling localities. Consequently, colonies in Namaqualand were genetically more diverse compared to those of the western Fynbos region. Two major matrilineal clades were evident on both side of the Knersvlakte - one to the north of this biogeographic break (Namaqualand), and the other to the south (western Fynbos). This was not, however, evident from the microsatellite data (reflecting the influence of male dispersal) where seven nuclear clusters were found. In keeping with other studies on saxicolous vertebrate taxa straddling the same region, this area of low connectivity has acted (and probably still does) as a barrier to gene-flow. Importantly, unlike in many other (admittedly invertebrate) species, no evidence of a genetic break was detected among hyrax populations across the Cape Flats. Colonies across the Hottentots Holland Mountains and Cape Peninsula regions may have been subject to founder-events and breeding isolation. This investigation demonstrated the importance of using a well-structured sampling regime that included both mitochondrial and nuclear markers and it underscores the need to apply appropriate statistical programmes for inferring genetic patterns. It shows that landscape genetics may be useful in a conservation context and should be taken into account when planning conservation initiatives that include the implementation of corridors. In brief, the information contained in this study advances our knowledge of the dispersal capability and genetic diversity of contemporary rock hyrax populations. / AFRIKAANSE OPSOMMING: ‘n Beperkte spreidingsvermoë, territorialiteit en die bewoning van yl-verspreide habitat is kenmerkend van die meeste klip-bewonende spesies in Afrika en dit veroorsaak gereeld gestruktureerde genetiese patrone met min of geen genevloei tussen populasies (bv., die velvetwurms, net-vlerk muggies, klipklaasneuse, klipkonyne en ‘n verskeidenheid akkedisse en koggelmanders). In ‘n poging om kennis oor taksa wat hierdie “terrestriële eilande” bewoon te verdiep, het ons die die verspreiding van genetiese variasie bestudeer oor verskeie ruimtelike skale in die klipdassie, Procavia capensis. Hierdie spesie het ‘n veelwywige sosiale sisteem, wat vreemd is onder taksa met soortgelyke ekologiese vereistes, en ‘n morfologie wat intuïtief verbind kan word met swak spreidingsvermoëns (kort bene en ‘n kort, dik liggaam). As ‘n moontlike resultaat van hierdie oorwegings het min studies tot dusver daarop gefokus om die migrasie-afstand van klipdassies en die invloede van hulle sosiale sisteem en die omliggende landskap op spreidings-sukses te bepaal. Hierdie studie toets daarom hipoteses oor hoe die ekologie, verspreiding, sosiale struktuur en die konnektiwiteit (verbindheid) van die omliggende landskap bydra om die struktuur van genetiese variasie in klipdassies oor die Namakwaland en westelike Fynbos streke te beïnvloed. Derhalwe is mitochondriale en mikrosatelliet merkers gebruik om genevloei te bepaal op ‘n fyn ruimtelike skaal (‘n geïsoleerde populasie bestaande uit 5 koppies), ‘n gemiddelde ruimtelike skaal (oor bekende geografiese grense vir klipbewonende taksa - die Kaapse Vlakte en die Knersvlakte), en op ‘n streeks (groot) ruimtelike skaal (oor die Namakwaland/westelike Fynbos streke van Suid-Afrika - streke met kontrasterende konnektiwiteit van die landskap). Bykomend is die genetiese diversiteit, ruimtelike groepering, seksuele eensydigheid in spreiding en genetiese verwantskappe (fyn skaal) van kolonies beskryf en die hoof genetiese skeiding gedateer deur gebruik te maak van ‘n ontspanne molekulêre klok. Laastens het is die resultate van hierdie studie vergelyk met dié van ander studies wat die Kaapse Vlakte en Knersvlakte as filogeografiese skeidings gevind het. Die genetiese patrone op ‘n fyn ruimtelike skaal was kompleks: Genevloei is beperk deur die sosiale struktuur van die klipdassie eerder as geografiese afstand, migrasie was wyfie-spesifiek en daar was beduidende genetiese struktuur tussen kolonies. Genevloei was beperk in die Hottentots Holland berge en die Kaapse Skiereiland (in beide datastelle) in vergelyking met lokaliteite oor die Kaapse Vlakte. In kontras was genevloei oor die Knersvlakte beperk in die mitochondriale DNA, maar nie in die mikrosatelliete nie. ‘n Soortgelyke patroon is waargeneem op ‘n streeks skaal wat dui op mannetjie-spesifieke spreiding in hiérdie spesie - ‘n resultaat van die veelwywige sosiale struktuur. Bykomend, saam met geslag-spesifieke spreiding, het landskaps konnektiwiteit ook genevloei beïnvloed op ‘n streeks skaal omdat die Namakwaland streek, wat meer tussenleggende geskikte habitat bevat in vergelyking met die westelike Fynbos streek, beduidende hoër vlakke van genevloei tussen lokaliteite getoon het. Gevolglik was kolonies in Namakwaland geneties meer divers in vergelyking met dié van die westelike Fynbos streek. Twee hoof moederlike genetiese groepe is waargeneem op elke kant van die Knersvlakte - een aan die noorde van hierdie biogeografiese skeiding (Namakwaland) en een in die suide (westelike Fynbos). Dieselfde patroon was egter nie waarneembaar in die mikrosatelliet data nie (wat die invloed van mannetjie-spesifieke spreiding toon) waar sewe nukluêre groepe gevind is. In ag genome ander studies op klipbewonende gewerwelde taksa oor dieselfde verspreiding, het hierdie area van lae konnektiwiteit histories (en heelmoontlik ook huidiglik) as ‘n grens vir genevloei gedien. Belangrik, anders as in ander (hoewel ongewerwelde) spesies, kon ons geen bewyse verskaf van ‘n genetiese skeiding tussen klipdassie populasies oor die Kaapse Vlakte nie. Kolonies in die Hottentots Holland berge en Kaapse Skiereiland is dus onderhewig aan moontlike vestigings-effekte en telings-isolasie. Hiérdie studie demonstreer die belang van die gebruik van ‘n goed-gestruktureerde monsternemingskema, die insluiting van beide mitochondriale en nukluêre merkers en dit beklemtoon ook die noodsaaklikheid van die gebruik van toepaslike statistiese programme vir gevolgtrekkings oor genetiese patrone. Dit toon ook dat landskapsgenetika nuttig mag wees in ‘n bewaringskonteks en in ag geneem moet word in die beplanning van bewarings inisiatiewe wat die implementering van korridors insluit. Kortliks, die informasie in hierdie studie bevorder ons kennis oor die spreidingsvermoë en genetiese diversiteit van kontemporêre klipdassie populasies.

Thesis (MSc)--Stellenbosch University, 2014. / ENGLISH ABSTRACT: Knowledge of the diversity and evolutionary histories of insects in South Africa’s fynbos biome lags far behind what is known of the plant groups that make up this global biodiversity hotspot. To address this imbalance, I undertook a molecular phylogenetic study of fynbos-endemic Cephalelini leafhoppers that specialise on restios in the family Restionaceae. My phylogenetic results did not recover the South African Cephalelini as monophyletic, nor did I find monophyly of described species, but several monophyletic clades of species were found within Cephalelini. Furthermore, phylogenetic dating suggested that the divergence between South African and Australian Cephalelini post-dates Gondwanan vicariance, implying intercontinental extreme long distance dispersal of these insects ca. 5-11 MYA. Diversification within the Cephalelini is also much more recent than that of the Restionaceae hosts on which they specialise, negating the possibility of coevolution between plants and insects. Rather, analysis of phylogenetic conservatism of host use reveals that Cephalelini evolution has tracked the evolution of their Restionaceae hosts and that closely related insects feed on the same plant host tribes. A finer scale of tracking of host evolution (such as at the clade or genus level) is expected when taking into account how highly specific I find Cephalelini host use to be, but its absence might be explained by the recent divergence of Cephalelini relative to the age of Restionaceae. Analysis of conservatism of host use was also carried out using a phylogeny of the Restionaceae, and revealed that, overall, Cephalelini host use and avoidance have no phylogenetic bias, indicating many empty potential niches for Cephalelini, or alternately that host use is governed by factors which are phylogenetically unconstrained. Lastly, I also analysed the evolution of specialisation of Cephalelini and find no trend towards increased specialisation within the group, which is contrary to what is expected of the evolution of herbivorous insects. Overall, this study presents the first evidence of intercontinental dispersal of insect fauna between South Africa and Australia and as such highlights an unconsidered factor in the accumulation of faunal diversity in the fynbos biome. I find Cephalelini to be highly specialised in their host preference, but this pattern only becomes apparent at the tribal host level in the evolution of Cephalelini. Although Cephalelini are highly specialised, I find no evidence of evolution towards increasing specialisation within the group. / AFRIKAANSE OPSOMMING: Ons kennis van die evolusie van fynbosinsekte is redelik beperk vergeleke met hoe veel ons weet van die plante wat die merkwaardige diversiteit van die fynbos-bioom uitmaak. In `n poging om hierdie wanbalans reg te stel het ek `n molekulêr-evolusionêre studie onderneem van die fynbos-endemiese blaarspringer-groep Cephalelini, wat op Restionaceae-gasheerplante spesialiseer. Ons het drie geen-areas geamplifiseer vir filogeniekonstruksie en dateringsdoeleindes: insek-kern H3, insek- mitokondriaal COI en insek-simbiont Sulcia 16S. Met behulp van filogenetiese analise is bevind dat die Suid-Afrikaanse Cephalelini nie `n monofiletiese groep is nie en dat beskryfde spesies ook nie monofileties is nie, maar verskeie monofiletiese spesie-groepe is wel gevind. `n Oorkruis-gevalideerde dateringsoefening dui aan dat divergensie tussen Suid-Afrikaanse en Australiaanse Cephalelini meer onlangs as die verbrokkeling van Gondwana plaasgevind het, wat impliseer dat daar uitruiling van insekte tussen die kontinente oor die afgelope 5-11 MJ plaasgevind het. Die diversiteit van Cephalelini het ook veel meer onlangs ontstaan as dié van hulle Restionacaea-gashere wat beteken dat ko-evolusie in die eng sin nie moontlik is nie. ‘n Ontleding van die evolusie van gasheer-keuse deur Cephalelini dui wel aan dat Cephalelini-evolusie die patron van hul Restionaceae-gashere volg en dat naverwante Cephalelini dieselfde stam van Restionaceae as gashere verkies. Die bevinding dat die Cephalelini hoogs gespesialiseerd is in hulle gasheer-keuses lei ‘n mens tot die verwagting dat die evolusie van Cephalelini meer getrou die evolusie van hulle gashere sal volg as wat wel die geval is (dalk op die vlak van groep of genus), maar die relatiewe jeugdigheid van die Cephalelini vergeleke met die ouderdom van die Restionaceae is moontlik die rede hiervoor. Analise van gasheer-keuse is ook uitgevoer op `n filogenie van die Restionaceae wat aantoon dat daar nie ‘n beperking van verwantskappe is tussen gashere wat verkies of verwerp word nie, wat daarop dui dat daar `n menigte nisse is wat oënskynlik onbenut is, of dat Cephalelini gasheer-keuse bepaal word deur `n Restionaceae-eienskappe wat nie filogeneties beperk is nie. Laastens het ek die evolusie van spesialisering deur Cephalelini ontleed, maar geen neiging tot toenemende spesialisering binne die groep gevind nie, wat onverwags is in die lig van vorige studies. As `n geheel bied hierdie studie die eerste bewys van die uitruiling van insek-fauna tussen die Suid-Afrikaanse fynbos-bioom en ander kontinente, wat `n onopgetekende invloed op die diversiteit van diere in die fynbos is. Cephalelini is `n hoogs gespesialiseerde groep insekte, maar uit `n filogenetiese perspektief word dit eers waargeneem op die vlak van gasheerstam. Ten spyte van hulle hoë vlak van spesialisering het ek geen bewys gevind van `n toename daarin binne die evolusie van die groep nie.

Thesis (MSc)--Stellenbosch University, 2014. / ENGLISH ABSTRACT: Research into the patterns and drivers of insect diversity in the Cape Floristic Region (CFR) lags far behind that of plants. Here I sample insect herbivore communities on a dominant plant family (Restionaceae), and use a spatially nested sampling design and network analysis to evaluate the association between plant and insect diversity in the CFR. I find that plant species richness predicts insect richness better than environmental factors. Turnover in insect communities is strongly associated with turnover in plant (both species and phylogenetic) communities at both local and regional sampling scales, suggesting insect host specificity. Plant communities unsurprisingly show significant turnover at small spatial scales (i.e. communities situated 0.1-3 km apart show significant turnover and may be tied to ecological niches). Insects show a similar pattern, but the decrease in community overlap is more gradual, suggesting many insects can utilise multiple (possibly closely related) hosts while plants are tied to particular niches. The emergent structure of multiple interaction networks is spatially and temporally invariant, despite high compositional change. However, the internal structure of the networks shows variation (i.e. interactions show spatial and temporal turnover). Seasonal interaction turnover is driven by a turnover in herbivores and by herbivore host switching. Spatially the turnover in interactions is driven by simultaneous turnover in both plants and insects, either suggesting that insects are host specific, or that both groups exhibit parallel responses to environmental gradients. Spatial interaction turnover is also driven by a turnover in plants, showing that many insects can utilise multiple (possibly closely related) hosts and have wider distribution ranges than their host plants. Results point toward insect host specificity, but probably not at the species level, as the primary mechanism structuring insect communities associated with the Restionaceae in the CFR. / AFRIKAANSE OPSOMMING: Navorsing wat verband hou met die patrone en meganismes wat insekdiversiteit in the Kaapse Blommeryk (KBR) hou nie pas met dié van plante nie. In hierdie studie neem ek insekmonsters binne een van die dominante plantfamilies (Restionaceae), en gebruik ‘n ruimtelik geneste ontwerp en netwerkanalise om die verbintenis tussen plant- en insekdiversiteit te evalueer. Ek vind plantrykheid voorspel insekrykheid beter as enige omgewingsfaktore. ‘n Omset in in insekgemeenskappe is sterk verbind aan ‘n omset in plantgemeenskappe (beide spesie en filogenetiese) by beide plaaslik en vir die hele streek. Hierdie dui op insekgasheerspesifisiteit. Plantgemeenskappe wys omset teen kort ruimtelike skale (0.1-3 km). Insekte wys ‘n soortgelyke patron, maar die afname in oorvleueling tussen gemeenskappe is meer geredelik. Dit dui dat insek meer as een gasheer kan gebruik, terwyl plante streng tot sekere nisse verbind is. Die ontluikende struktuur van menigde interaksienetwerke wys geen ruimtelike of tydelike variasie nie, ten spyte van hoë gemeenskapsomset. Nietewel, die interne struktuur van die netwerke wys veranderinge (interaksies in netwerke wys omset). Seisonale interaksie-omset kan toegeskryf word aan ‘n omset van herbivore en insekgasheerverandering. Ruimtelike interaksie-omset word toegeskryf aan gelyktydige insek- en plantomset, wat óf deur insekgasheerspesifisiteit veroorsaak word óf deur parallele reaksies tot omgewingsveranderinge. Ruimtelike interaksie-omset word ook deur plantomset beïnvloed, wat aandui sommige insekte kan meer as een gasheer benut en insekte het weier verspreidings as hul gasheer. Resultate dui daarop dat insekgasheerspesifisiteit, maar waarskynlik nie op die spesievlak nie, moontlik die primêre meganisme is wat insekgemeenskappe verbind aan die Restionaceae in die KBR struktureer.

Thesis (Ph.D)--Stellenbosch University, 2000. / ENGLISH ABSTRACT: Copper oxychloride is a fungicide that is extensively used in vineyards in the Western Cape to treat and prevent fungal diseases. It is however not clear what the effects are on soil organisms, which play an important role in soil fertility, in South African soils. There is paucity of data linking results obtained in the laboratory to effects observed in the field, which will only become useful if a clear relation can be demonstrated. The aims of this study were to: ~ Determine the effects of copper oxychloride on field populations of earthworms and simultaneously monitor lysosomal membrane stability, measured as neutral red retention time (NRRT). ~ Validate experimental field studies by doing inventories of earthworm populations in long-term sprayed vineyards. ~ Determine the LC50 of copper oxychloride and simultaneously measuring NRRT, and linking them to the experimental field studies. ~ Conduct bioassays, burrowing activity- and soil-avoidance experiments to investigate their relations to earthworm population responses in the experimental field studies. Earthworms were sampled by hand-sorting in the field tests on treated and untreated field plots in the Western- (October 1998 - July 1999) and Northern Cape (April 1998 - October 1999). Soil samples and worms were analysed for copper contents and coelomocytes of live earthworms were used to conduct the neutral red retention assays. Acute toxicity tests were conducted over a period of 28 days during which the earthworms (Eisenia fetiday were exposed to different concentrations of copper oxychloride. Change in biomass and mortality were measured as endpoints, as well as NRRT. Bioassays, burrowing activity and soil-avoidance were conducted by exposing Aporrectodea caliginosa to grassland- and vineyard soil as well as grassland soil spiked with 60 J.1g.g-1copper in the form of copper oxychloride. Growth and mortality were recorded in the bioassays as well as copper concentrations In earthworm body tissues and substrates used over a period of28 days. Burrowing activity and soil-avoidance were determined by measuring the length of tunnels burrowed by A. caliginosa in soil profiles over a period of 4 days under different exposure regimes. Results from the field tests showed that spraying of copper oxychloride had a negative effect on earthworm populations at the prescribed application rates. NRR T in earthworms from the exposure plots was significantly (p<0.05) lower after just one spraying application. It was concluded that spraying copper oxychloride at prescribed application rates caused a decrease in field populations of earthworms and that NRRT was an early and reliable biomarker since it was indicative of later effects observed at the population level. Results obtained from the field inventory of earthworms in vineyards at Nietvoorbij, Robertson end Worcester confirmed data from the two field studies. The calculated LC50 of 882.78 I1g.g-1 for copper oxychloride and 519.40 I1g.g-1 for copper was ecologically relevant if a safety factor of 10 was applied. NRRT which manifested earlier than effects on biomass change in the acute toxicity tests, were significant when viewed against the background of responses of field populations of earthworms. From the bioassay experiments it was found that A. caliginosa exposed to copper oxychloride spiked soil had significantly (p<0.05) higher weight loss and mortality than those in grassland- and vineyard soil. This indicated that changes in biomass and mortality were indicative of population responses in the field and can be considered as ecologically relevant. Burrowing activity of A. caliginosa was significantly (p<0.05) lower in vineyard and copper oxychloride spiked soil than in grassland soil. Similarly in the soil avoidance experiments it was found that A. caliginosa avoided vineyard- and copper oxychloride contaminated soil. It is therefore concluded that burrowing activity and soil avoidance were ecologically relevant endpoints since they corresponded with population responses in the field. The study thus revealed that the long-term usage of copper oxychloride could have negative effects on earthworm populations. The spraying of copper oxychloride can have important implications on the sustainable use of agricultural soils since earthworms and other soil organisms play such an important role in soil fertility. The use of biomarkers and other ecotoxicological indicators can provide an early warning that soil organisms are under environmental stress. / AFRIKAANSE OPSOMMING: Die fungisied koperoksichloried word wyd gebruik in die Wes-Kaap om swamsiektes in wingerde te beheer en te voorkom. Dit is egter nie bekend wat die effek daarvan op Suid Afrikaanse grondbiota, wat 'n belangrike rol speel in grondvrugbaarheid, is nie. Daar is ook 'n tekort aan inligting wat die resultate van laboratoriumondersoeke in verband bring met veldstudies. Die doelstellings van die studie was om: ~ Die effek van koperoksichloried op erdwurmpopulasies in die veld te ondersoek en terselfdertyd membraanstabiliteit, as moontlike biomerker, gemeet as neutraal rooi retensietye (NRRT), te monitor. ~ Die geldigheid van eksperimentele veldstudies te toets deur ook grondanalises te doen in wingerde wat oor langtermyn met koperoksichloried bespuit is. ~ Die LC50 van koperoksichloried vir erdwurms te bepaal en terselfdertyd NRR T te meet asook om dié gegewens in verband te bring met die resultate van seisoenale veldstudies oor die uitwerking op erdwurmpopulasies. ~ Bio-evaluerings ("bioassays"), tonnelaktiwiteit- en vermydingseksperimente te onderneem en die verband tussen die toksiteitstoetse en populasieresponse, soos waargeneem in die veld, te ondersoek. Erdwurms is versamel deur handsortering tydens die veldtoetse in die Wes- (Oktober 1998 - Julie 1999) en Noord-Kaap (April 1998 - Oktober 1999) op kontrole en bespuite persele. Grondmonsters en erdwurms is spektrofotometries geanaliseer om koperinhoude te bepaal. Die selomosiete van lewende wurms is gebruik om NRR T te bepaal. Akute toksisiteitstoetse is uitgevoer oor 'n tydperk van 28 dae waartydens Eisenia fetida blootgestel is aan verskillende koperoksichloried konsentrasies. Veranderinge in biomassa en mortaliteit is bepaal asook NRRT. Bioevaluerings ("bioassays"), tonnelaktiwiteit- en vermydingseksperimente IS uitgevoer deur Aporrectodea caliginosa bloot te stel aan grasveld- en wingerdgrond asook grasveldgrond wat met koperoksichloried gekontamineer is. Groei en mortalitiet is bepaal in die "bioassays" asook koperkonsentrasies in die grond en erdwurm liggaamsweefsels oor 'n tydperk van 28 dae. Tonnelaktiwiteit en grondvermyding is bepaal deur die lengte van tonnels wat deur A. caliginosa gegrawe is te meet oor 'n tydperk van vier dae vir die verskillende blootgestelde groepe. Die resultate het aangedui dat koperoksichloriedbespuiting 'n negatiewe invloed het op erdwurmpopulasies teen die voorgeskrewe toedieningsprogram. NRRT in erdwurms van die blootstellingperseel, was beduidend (p<0.05) laer na 'n enkele bespuiting. Daar is verder bevind dat NRR T 'n betroubare en vroeë biomerker is, aangesien dit 'n aanduiding gegee het van latere effekte wat op populasievlak na vore getree het. Veldopnames in Nietvoorbij, Robertson en Worcester het die geldigheid van data verkry uit die veldstudies ondersteun. Die berekende LC50 van 882.78 ug.g" vir koperoksichloried en 519.40 ug.g" VIr koper was ekologies relevant indien 'n veiligheidsfaktor van 10 toegepas is. NRRT se ekologiese relevansie is bevestig deur dit te vergelyk met response wat in die veldtoetse waargeneem is. Deur bioevalueringseksperimente is bevind dat gewigsverlies en mortaliteit van A. caliginosa beduidend hoër was in koperoksichloried gekontamineerde grond as in die grasveld- (kontrole) en wingerdgronde. Veranderinge in biomassa en mortalitiet was aanduidend van populasieresponse soos waargeneem in die veldstudies en kan dus as ekologies relevante eindpunte beskou word. Tonnelaktiwiteit van A. caliginosa was beduidend (p<0.05) laer in wingerd- en koperoksichloried gekontamineerde grond as in grasveldgrond. Dieselfde is gevind in die grondvermydingstoetse waar A. caliginosa wingerd- en koperoksichloried gekontamineerde grond vermy het. Dit kan dus afgelei dat tonnelaktiwiteit en grondvermyding ook ekologies bruikbare eindpunte is aangesien dit verband hou met populasieresponse soos waargeneem in die veldstudies. Hierdie studie het getoon dat die herhaalde gebruik van koperoksichloried 'n nadelige invloed kan hê op erdwurmbevolkings. In die lig van die belangrike rol wat erdwurms en ander grondorganismes speel in grondvrugbaarheid kan die oormatige gebruik van hierdie fungisied ernstige implikasies inhou vir volhoubare benutting van landbougronde. Die gebruik van biomerkers en ander ekotoksikologiese eindpunte kan egter as vroeë waarskuwingsmetode dien dat die grondorganismes onder omgewingstres verkeer.

Thesis (PhD)--Stellenbosch University, 2002. / ENGLISH ABSTRACT: Metals occur naturally in the environment but since the industrial revolution the amounts ofbioavailable metals in the environment have increased significantly. There are various anthropogenic sources of metals in the environment. In recent years there has been an increasing interest in the use of biomarkers in terrestrial invertebrates for the assessment of the potential adverse effects of chemicals in soil ecosystems. Terrestrial isopods are one of the groups that play an important role in the decomposition process as fragmentors of dead plant material in soil ecosystems. They are also known to accumulate contaminants in their bodies, especially in the hepatopancreas. Cadmium has no known biological function and is deposited in the environment through a variety of sources. Zinc on the other hand is one of the essential metals and play an important role in the normal metabolism of animals. Zinc too, is deposited in the environment through a variety of anthropogenic sources. The aim of this study was to undertake an experimental and field evaluation of the role cellular change in the hepatopancreas of terrestrial isopods can play in conjunction with other sublethal responses to contribute to the assessment of the impact of cadmium and zinc in terrestrial ecosystems. Porcel/io laevis was used as test species in the laboratory experiments in this study, to conduct sublethal toxicity tests. Cadmium- and zinc sulphate were used as the contaminants, applied separately and as mixtures. The isopods were weighed before the beginning of the exposures and every week throughout the exposure period of six weeks. At the end of the exposure period they were dissected to remove the hepatopancreas. The zinc and cadmium content of the hepatopancreases and rest of the bodies of the isopods were determined by atomic absorption spectrophotometry. Hepatopancreas samples were also prepared for histological analysis, and measurements of the Percentage Cellular Area (PCA) were made using image analysis. Specimens of Porcellionides pruinosus were collected from contaminated- and uncontaminated field sites. Hepatopancreas- and rest of the body samples of P. pruinosus were also analysed for cadmium and zinc. Histological sections of the hepatopancreas were similarly prepared and analysed, as in the laboratory experiments. Exposure to cadmium- and zinc sulphate affected the mass of P. laevis negatively in the single metal exposures. However, these two metals "neutralised" each other's effects in the mixture toxicity exposures, pointing towards an antagonistic interaction. Administered cadmium- and zinc sulphate resulted in the accumulation of cadmium and zinc in the isopods, especially in the hepatopancreas. In the mixture toxicity experiments cadmium and zinc influenced the accumulation of each other. Cadmium- and zinc sulphate, whether administered separately or as mixtures, changed the structure of the hepatopancreas and this was quantitatively shown through PCA measurements. PCA of the hepatopancreas of terrestrial isopods was shown to be a good general biomarker of exposure and effects for cadmium as well as for zinc. It is suggested that PCA could serve as a general biomarker to predict possible impairment of growth or mass change of isopods exposed to cadmium and zinc mixtures. The findings of the field survey also suggest that PCA may be suitable to be used as a general biomarker to measure metal induced stress in woodlice from contaminated field sites. / AFRIKAANSE OPSOMMING: Metale kom natuurlik voor in die omgewing, maar sedert die industriële revolusie het die hoeveelheid bio-beskikbare metale in die omgewing betekenisvol toegeneem. Daar is verskeie antropogeniese bronne van metale in die omgewing. Die afgelope paar jaar was daar toenemende belangstelling in die gebruik van biomerkers by terrestriële invertebrate vir die assessering van potensiële negatiewe effekte van chemiese stowwe in grondekosisteme. Terrestriële Isopoda is een van die groepe wat 'n belangrike rol speel III die ontbindingsproses as fragmenteerders van dooie plantmateriaal III grondekosisteme. Hulle akkumuleer ook kontaminante in hul liggame, veral in die hepatopankreas. Kadmium het geen biologiese funksie nie, en word vrygestel in die omgewing deur verskeie bronne. Sink, aan die ander kant, is een van die essensiële metale en speel 'n belangrike rol in die metabolisme van diere. Sink word ook in die omgewing vrygestel deur 'n verskeidenheid antropogeniese bronne. Die doel van die studie was om deur eksperimentele en veldondersoek die rol van sellulêre veranderinge in die hepatopankreas van terrestriële Isopoda in samehang met ander subietale response te evalueer om by te dra tot die assessering van die impak van kadmium en sink op terrestriële ekosisteme. Porcellio laevis is as toets-spesie in die laboratorium eksperimente gebruik om subietale toksisiteitstoetse mee uit te voer. Kadmium- en sinksulfaat is as kontaminante gebruik, en is apart en gemeng toegedien. Die houtluise is geweeg voor die begin van die blootstellings en elke week deur die loop van die blootstellingsperiode van ses weke. Aan die einde van die blootstellingsperiode is hulle gedissekteer om die hepatopankreas te verwyder. Die sink en kadmium inhoude van die hepatopankreas en res van die liggame van die houtluise is bepaal met behulp van atoomabsorpsiespektrofotometrie. Monsters van die hepatopankreas is ook voorberei vir histologiese analise, en metings van die Persentasie Sellulêre Oppervlak (PSO) is gedoen met behulp van beeldanalise. Eksemplare van Porcellionides pruinosus is versamel van 'n gekontamineerde- en 'n ongekontamineerde gebied. Monster van die hepatopankreas en res van die liggaam van P. pruinosus is ook geanaliseer vir kadmium en sink. Histologiese sneë van die hepatopankreas was ook voorberei en geanaliseer, soos in die laboratorium eksperimente. Blootstelling aan kadmium- en sinksulfaat het die massa van P. laevis negatief beïnvloed in die enkelmetaal-eksperimente. Hierdie twee metale het egter mekaar se effekte in die mengseltoksisiteitstoetse "geneutraliseer". Dit dui op 'n antagonistiese interaksie. Toegediende kadmium- en sinksulfaat het gelei tot die akkumulasie van kadmium en sink in the houtluise, veral in die hepatopankreas. In die mengseltoksisiteitstoetse het kadmium en sink mekaar se akkumulasie beïnvloed. Kadmium- en sinksulfaat, apart of as mengsels toegedien, het die struktuur van die hepatopankreas verander, en dit is kwantitatief aangetoon deur die PSO metings. PSO van die hepatopankreas van houtluise is 'n bruikbare algemene biomerker van blootstelling en effek vir kadmium en sink. Dit word voorgestel dat PSO kan dien as 'n algemene biomerker om negatiewe effekte op die groei of massaverandering van houtluise te voorspel wat aan kadmium en sink mengsels blootgestel word. Die bevindinge van die veldondersoek dui daarop dat PSO gepas mag wees om gebruik te word as 'n algemene biomerker om metaal-geïnduseerde stres by houtluise vanaf 'n gekontamineerde gebied te meet.

Thesis (PhD (Botany and Zoology))--Stellenbosch University, 2011. / ENGLISH ABSTRACT: Insect societies utilize advanced chemical communication systems to organize many aspects of their social life, which among others, include reproduction, thus maintaining colony homeostasis. The queen pheromone complex (QMP), dominated by (E)-9-keto-2-decenoic acid (9ODA) is of integral importance in regulating worker reproductive development. Unique characteristics, associated with reproductive dominance, enabled the successful establishment of Apis mellifera capensis workers as social parasites (or pseudoqueens) in colonies of the neighbouring A. m. scutellata. This suggested that producing a queenlike pheromonal bouquet is one of the proximate factors in their success. In this study we attempted to address the pheromone communication dilemma by investigating whether the phenotypic expression of mandibular gland signals in honeybee workers are under genetic and/or environmental influence. It was hypothesized that the mandibular gland profiles of queens and workers may be closely correlated to specific genotypes in the colony. However, different ageing and rearing environments (social context) can ultimately influence gene expression with respect to mandibular gland signals, highlighting the fact that environmental influences are not necessarily non-significant. In our experiments, both environmental/social conditions and genotypes of our test individuals were manipulated. The capensis workers used in our experiment from their native range (Western Cape area are refered to as native workers, while capensis parasitic workers, from the clonal parasitic lineage, were obtained from the Gauteng area. A. m. scutellata workers were obtained from their native range, north of the hybrid zone. Both native and parasitic workers showed the potential to become reproductively active, but the rapid pheromonal development of parasitic workers placed them at a reproductive advantage. Parasitic workers started producing low levels of 9HDA, the precursor to the queen substance 9ODA, between 12-24 hrs, while native workers only did so after 24 hrs. Despite this, rapid signal development did not culminate in the parasitic clones always pheromonally out-competing native workers. Withinin groups of native workers and a single clonal parasitic worker, the mandibular gland profiles of most workers were dominated by 9ODA and 9HDA (> 80% of extracts) with only 43% of the single parasitic workers producing higher amounts of 9ODA than native workers. Mandibular gland pheromone profiles converged in groups of workers sharing a greater proportion of genes, providing support for a link to genotypic affects. Workers that were 75 – 99% related diverged significantly from groups with lower levels of relatedness was largely due to the presences of 9ODA (Spearman’s rank correlation r = 0.66, p < 0.0001). Despite the tendency for signal to convergence in groups of closer relatedness a considerable amount of signal variability was also observed under varying social conditions. Workers originating from a single capensis queen but aged under queenright and queenless conditions had very distinct mandibular gland profiles (Wilks’ lambda λ = 0.118, χ2 = 331.002, p < 0.0001). This variability was thus a result of the social environment that the workers were exposed to. The physiological traits, namely mandibular gland pheromone production, linked to reproductive potential in honeybee workers seem to be determined by a combination of environmental and genetic factors. Queen mandibular gland pheromone biosynthesis is genetically predisposed in certain workers however the final oxidation step to 9ODA is strongly influenced by the social environment. The signal plasticity observed in this study is adaptive and assists workers to realize their reproductive potential. / AFRIKAANSE OPSOMMING: Insek gemeenskappe gebruik gevorderde chemiese kommunikasie sisteme om verskeie aspekte van sosiale lewe, onder andere reproduksie, te organiseer en sodoende word korf homeostasis handhaaf. Die feromoon kompleks van die koninginby, wat hoofsaaklik uit (E)-9-keto-2-decenoic acid (9ODA) bestaan speel ʼn belangrike rol in die regulering van reproduksie in heuningby werkers. Die suksesvolle vestiging van Apis mellifera capensis werkers as sosiale parasiete (pseudo koninginne) in die korwe van die naburige A. m. scutellata, is bewerkstellig deur hul unieke kenmerke, wat met reproduktiewe oorheersing verband hou. Dit suggereer dat die produksie van ʼn tipiese koningin feromoon sein een van verskeie beduidende faktore is in capensis werkers se sukses. In hierdie studie het ons die dilemma van feromoon kommunikasie probeer aanspreek deur te ondersoek of die fenotipiese uitdrukking van seine van die mandibulêre kliere deur genetiese en/of omgewings faktore beïnvloed word. Die hipotese was dat die mandibulêre klier profiele van koninginne en werkers korreleer met spesifieke genotipes in die korf. Die verskillende omgewings waarin werkers groot gemaak word en verouder (sosiale konteks), kan uiteindelik die uitdrukking van gene, raakende mandibulêre kliere, beïnvloed. Dit beklemtoon die feit dat omgewings faktore nie noodwendig onbeduidend is nie. Beide omgewings/sosiale toestande and genotipes van toets individue is in ons eksperimente gemanipuleer. Die capensis werkers afkomstig uit hul natuurlike habitat (Weskaap area) wat in ons eksperimente gebruik is word na verwys as inboorling werkers, terwyl parasitiese capensis werkers, van klonies parasitiese afkoms, vanuit die Gauteng area verkry is. A. m. scutellata werkers was vanuit hul natuurlike habitat, noord van die, hybried sone, verkry. Beide inboorling en parasitise werkers het die potensiaal getoon om reproduktief aktief te word, maar versnelde feromoon ontwikkeling van parasite werkers het hulle ʼn reproduktiewe voordeel gegee. Parasiet werkers het reeds lae hoeveelhede 9HDA, die voorganger van 9ODA, begin produseer tussen 12 – 24 uur, terwyl inboorling werkers produksie eers na 24 uur begin het. Ten spyte van die versnelde ontwikkeling in parasiet werkers het dit nie gelei daartoe dat kloniese parasiete altyd feromonies die oorhand oor inboorling werkers gekry het nie. In groepe bestaande uit inboorling werkers en ʼn enkele parasite werker, was die mandibulêre klier profiele altyd deur 9ODA en 9HDA (> 80% van ekstrakte) gedomineer. Slegs 43% van parasite werkers het groter hoeveelhede 9ODA as inboorling werkers geproduseer. In groepe werkers, wat ʼn groter proporsie gene in gemeen gehad het, het mandibulêre klier profiele konvergeer. Dit ondersteun die bestaan van ʼn verband met genotipiese invloed. Werkers van 75 – 99% verwantskap het beduidend verskil van groepe met laer verwantskapsvlakke, hoofsaaklik as gevolg van die teenwoordigheid van 9ODA (Spearman’s rank korrelasie r = 0.66, p < 0.0001). Ten spyte van die konvergerende neiging van profiele, van meer verwante groepe, was aansienlike veranderlikheid onder verskillende sosiale toestande waargeneem. Werkers, afkomstig vanaf ʼn enkele capensis koninginby, maar òf in die teenwoordigheid òf afwesigheid van ʼn koningin verouder is, het baie kenmerkende mandibulêre klier profiele getoon (Wilks’ lambda λ = 0.118, χ2 = 331.002, p < 0.0001). Die veranderlikheid was dus ʼn gevolg van die sosiale omgewing waaraan die werkers blootgestel was. Dit blyk asof die fisiologiese kenmerke wat met reproduksie potensiaal in heuningbye verband hou, naamlik mandibulêre klier feromoon produksie, deur ʼn kombinasie van genetiese – en omgewings faktore beïnvloed word. Sekere werkers is meer geneig tot die biosintese van koningin mandibulêre klier feromoon as gevolg van hul genetika, terwyl die finale oksidasie na 9ODA onder sterk omgewings invloed is. Die plastisiteit in mandibulêre seine waargeneem in hierdie studie, is aanpasbaar en help werkers om hul reproduksie potensiaal te bereik.

Thesis (PhD (Botany and Zoology))--Stellenbosch University, 2011. / ENGLISH ABSTRACT: With the current global decline in pollinators, and the concurrent decline in plant species, pollination research is becoming increasingly important. However, studies outside Europe and North-America and on groups other than insects are needed to make generalisations possible. In this thesis I study how pollination structures plant and bird communities in a biodiversity hotspot, the Cape Floristic Region of South Africa. I show that bird-plant pollination mutualisms are an important ecological factor structuring ornithophilous Proteaceae and nectar-feeding bird communities. This close association between plant and bird communities suggests an important role for community wide pollination mutualisms. How these mutualisms disassemble in reaction to a range of anthropogenic impacts is determined. Firstly, I use experimental manipulation of honeybee density to test whether honeybee farming affects nectar-feeding birds. Hive addition increased honeybee abundance far above natural levels but nectar-feeding bird pollinators were not consistently affected. Secondly, I document the impact of a two lane tar road on the bird pollination community. The two-fold decline found in pollination along roadsides, should have important implications for the way we view and manage road verges for ecological processes. Thirdly, I investigated how fragmentation affects bird-pollination communities by assessing an endangered, bird-pollinated plant, Brunsvigia litoralis. The only flower visitor at the urban sites, the shorter billed Greater Double-collared Sunbird is unable to access the nectar due to a long perianth tube. The longer billed Malachite Sunbird was the sole pollinator of B. litoralis at the rural site, significantly increased seed set. The lack of ecological analogs in these urban fragments might place pollinator specialist plants, such as B. litoralis, at risk. Fourthly, fire is a frequent disturbance in communities of bird-pollinated plants. In a before/after fire observation study and a burnt/unburnt transplant study, birds visited flowers in the “before fire” and “unburnt” areas only. The results are surprising given the large number of bird-pollinated plants flowering in the early post-fire vegetation. Lastly, I find that alien invasive plant species are incorporated into the native pollination community in a spectacular way; sunbirds adapt to a hummingbird-like, hovering lifestyle to obtain nectar. Alien invasive plants greatly increase nectar-feeding bird abundance; in turn, birds enhance seed set in these alien plants. I conclude by asking whether the disassembling of bird pollination communities really matters. To answer this question I report on a decade of demographic data on the geophytic bird-pollinated Brunsvigia orientalis. In the demographic analysis, the elasticity component for reproduction was more important than expected for a long lived plant. Reduced population growth in the shade and a large investment in a winged inflorescence, suggest B. orientalis is a light demanding, well dispersed, gap colonising species. The link between pollination and seed has been made before, but I take this one step further and show that pollination intensity predicts population growth rate. By linking plant demography and pollination, I was able to predict the future of plant populations under variable pollination conditions. The disassembly of bird pollination communities only becomes important for population persistence once the mutualism has almost entirely broken down. / AFRIKAANSE OPSOMMING: Met die huidige globale afname in bestuiwers en die gelyktydige afname in plant spesies, word bestuiwing navorsing toenemend belangrik. Studies buite Europa en Noord-Amerika en op groepe anders dan insekte is nodig on veralgemenings moontlik te maak. In hierdie tesis bestudeer ek hoe bestuiwing struktuur gee and plant en voël gemeenskappe in 'n biodiversiteit hotspot, die Kaapse Floristiese Ryk van Suid-Afrika. Ek wys dat voël-plant bestuiwings mutualismes 'n belangrike ekologiese faktor is in die strukturering van voël bestuifde Proteaceae gemeenskappe en nektar-etende voël gemeenskappe. Hierdie noue assosiasie tussen plant en voël gemeenskappe impliseer 'n belangrike rol vir gemeenskapwye bestuiwings meganismes. Ek bepaal hoe hierdie mutualismes aftakel in reaksie op 'n verskeidenheid van antropogeniese impakte. Eerstens gebruik ek 'n eksperimentele manipulasie van heuningby getalle om te toets of bye boerdery nektar-etende voëls affekteer. Byekorf toevoeging het heuningby getalle laat toeneem tot ver bo natuurlike vlakke maar nektar-etende voël bestuiwers is nie konsekwent beïnvloed nie. Tweedens dokumenteer ek die impakte van 'n twee baan teerpad op die voël bestuiwings gemeenskap. Die twee-malige afname in bestuiwing langs paaie sal belangrike implikasies hê vir die manier hoe ons pad reserwes sien en bestuur met betrekking tot ekologiese prosesse. Derdens bestudeer ek hoe fragmentasie die voël-plant gemeenskappe affekteer deur die bedreigde voël-bestuifde Brunsvigia litoralis te assesseer. Die enigste besoeker in die meer stedelike area, die Groot-rooibandsuikerbekkie, wat 'n korter snawel het, is nie in staat om die nektar te bereik nie, weens 'n te lang blombuis. Die Jangroentjie suikerbekkie met sy langer snawel is die enigste bestuiwer van B. litoralis in die meer landelike area, met 'n betekenisvolle vermeerdering in saad vorming. Die gebrek aan ekologies analogiese spesies in die stedelike fragmente kan 'n risiko inhou vir bestuiwer gespesialiseerde plante soos B. litoralis. Vierdens, vuur is 'n gereelde versteuring van voël-plant gemeenskappe. In 'n voor/na vuur observasie studie en 'n brand/nie-brand verplasing studie, het voëls blomme net in die “voor brand” en “nie-brand” areas besoek. Hierdie resultate is verrassend siende die groot hoeveelheid voël-bestuifde plante wat blom direk na brande. Laastens het ek gevind dat uitheemse indringer plante geïnkorporeer word in die inheemse bestuiwers gemeenskappe op 'n skouspelagtige manier; suikerbekkies pas aan tot 'n kolibri-tipe, fladderende lewenswyse om nektar te bekom. Uitheemse indringer plante het nektar-etende voël hoeveelhede laat toeneem; in reaksie het voëls saad opbrengs vermeerder. In konklusie vra ek of hierdie aftakeling van die voël bestuiwers gemeenskap belangrik is. Om hierdie vraag te antwoord assesseer ek 'n dekade van demografiese data van die geofietiese, voël-bestuifde plant, Brunsvigia orientalis. In die demografiese analises was die elastisiteit komponent van reproduksie belangriker as verwag vir 'n langlewende plant. Verminderde populasie groei in die skaduwee en 'n hoë investering in 'n gevlerkte bloeiwyse suggereer dat B. orientalis 'n lig afhanklike, goed verspreide, gaping koloniserende spesie is. Die skakel tussen bestuiwing en saadvorming is voorheen gemaak, maar ek neem dit een stap verder en wys dat bestuiwings intensiteit populasie groeikoers voorspel. Deur plant demografie en bestuiwing te koppel was ek in staat om die toekoms van populasies onder variërende bestuiwings kondisies te voorspel. Die aftakeling van voël bestuiwings gemeenskappe word slegs belangrik vir populasies se voortbestaan wanneer die mutualisme amper heeltemal verdwyn het.