Thesis (PhD)--Stellenbosch University, 2013. / Pollinators play a fundamental role in floral evolution. They can exert selection on the flowers they visit in a plethora of different ways, ranging from innate floral preferences to differences in body size and shape and behavioural elements such as flower constancy and learning capacity. Since different pollinators exhibit differences in these characters, shifts between pollinating species are often considered the most likely drivers of floral diversification. While many lines of evidence support this claim, numerous angiosperms pollinated by a single species also exhibit floral variation. Throughout my thesis, I explore and investigate floral diversification in such species in the absence of pollinator shifts. In Chapter 2, I investigate variation in the preference of conspecific male and female pollinators for the floral traits of a sexually deceptive daisy that comprises distinct floral forms. I show that its pollinator exhibits gender-specific variation in floral preferences, and that some floral forms have specialized on the male pollinator. This chapter thus illustrates the importance of intraspecific variation in pollinator preference for floral diversification, an underappreciated mechanism in this field of research. The innate preferences of pollinators are likely to have a genetic basis, especially innate preferences that govern mate choice. Genetic structure within the pollinators of sexually deceptive plants, which mimic female insects to achieve pollination, may thus provide an important source of selection on the plants they pollinate. This depends on an association between genetic divergence and divergent mate preferences, and I explore this intriguing idea in Chapter 3. While pollinators associated with sexually deceptive floral forms did exhibit significant genetic structuring, male pollinators from different phylogeographic clades all exhibited preference for the same sexually deceptive floral form, thus rejecting this hypothesis. Another behavioural attribute of pollinators that may affect floral evolution, particularly in deceptive plant species, is learning ability. Studies on sexually deceptive orchids often report that male pollinators tend to avoid sexually deceptive flowers with experience. In Chapter 4, I systematically investigate learning abilities within male pollinators and the costs they suffer on sexually deceptive floral forms that vary in deceptiveness. Results reveal a positive relationship between the level of floral deceptiveness and the 4 associated mating costs that deceived males suffer. Pollinator learning, however, appears to occur only on the most deceptive floral forms, suggesting a link between the costs suffered to the occurrence of learning. In Chapter 4, I systematically investigate learning abilities within male pollinators and the costs they suffer on sexually deceptive floral forms that vary in deceptiveness. Results reveal a positive relationship between the level of floral deceptiveness and the associated mating costs that deceived males suffer. Pollinator learning, however, appears to occur only on the most deceptive floral forms, suggesting a link between the costs suffered to the occurrence of learning. In Chapter 5, I explore the importance of florivory damage in a polymorphic daisy. Studies on floral evolution often overlook the significance of florivorous visits and focus only on pollinator-mediated selection. I show that floral polymorphism is maintained by antagonistic selection exerted by pollinators and florivores on the same floral traits. Lastly, I focus on evolutionary history to explore similarity in the patterns of South African angiosperm evolution and the pollinator species used throughout my thesis. Molecular dating shows this pollinator exhibits broadly congruent evolutionary patterns to these angiosperms, indicative of a shared biogeography. Taken together, my thesis demonstrates the vast impact of floral visitors, in particular pollinating insects, on the evolution of floral form. / My research was funded by the National Research Foundation of South Africa (NRF) and personal funding was provided by a NRF Innovation scholarship and merit bursaries from the Botany and Zoology department at Stellenbosch University. A WhiteSci Travel Grant and financial support from Prof. Erik Svensson at Lund University also allowed me to present parts of my research at international conference.

Made available in DSpace on 2016-06-02T18:55:29Z (GMT). No. of bitstreams: 1 6602.pdf: 1881410 bytes, checksum: 876d6a2701ccd375193781c4bc7209f1 (MD5) Previous issue date: 2015-02-26 / Financiadora de Estudos e Projetos / The pollination is am essential environmental service to the development of various plant species, contributing to the provision of basic human food. Some species, like much of the genus Solanum, may present different floral morphs, which in turn can influence its reproduction. In this context, this study aimed to study the biology of pollination of Solanum melongena L. (Solanaceae). The specific objectives were: 1) to analyze the biology and floral morphology of the species; 2) verify the reproductive and sexual system of the species; and 3) to verify the wealth and the behavior of your floral visitors. The study was conducted in two areas of conventional agricultural crop in Estiva Gerbi and Piracicaba, both in the state of São Paulo. The floral visitors were observed between February and June 2014. The data of floral morphometry were collected with the aid of manual caliper and the differences between the measures were tested using the t test. The estimation of pollen production was given by counting the number of grains produced by anther. The number of viable pollen grains was quantified by cytoplasmic staining, with the technique of acetic carmine. To investigate the relationship between the frequency of pollinators and the availability of pollen, we calculated the Pearson correlation coefficient (r). To check the effectiveness of different pollinators in the formation of fruits and seeds of eggplant, we selected two species of bees with different foraging behaviors: Apis mellifera, which does not vibrate and Exomalopsis diminuta, which vibrates the flower anthers to release pollen. Variance analyses were performed to detect significant differences between fruits developed by both species. The reproductive system was analyzed by the formation of pollen tubes at different times after pollination different treatments are performed. Through the morphometric analysis, there was significant difference between the floral and reproductive structures of different morphs, featuring a polymorphism condition in style size to S. melongena. The observations found the presence of the bee genera Bombus, Xylocopa, Apis, Trigona, Pseudaugochloropsis, Oxaea and Exomalopsis. Concerning the behavior of each species, there has been a change both in relation to the form of collecting pollen on the flower in the length of stay. Concerning the reproductive system, it was noted formation of pollen tubes along the style and the same coming to ovule only in long style flowers, which may indicate a andromonoecious condition for the species under study. It is concluded for S. melongena that the action of pollinators is of great importance for its development, since even being self-compatible, the spontaneous self not proved to be sufficient for effective fertilization of their ovules. There are several species that play role of pollinators, but species with the vibration behavior contribute more effectively to the development of this culture. / O processo de polinização é um serviço ecossistêmico fundamental para o desenvolvimento de diversas espécies vegetais, contribuindo largamente para o fornecimento da base da alimentação humana. Algumas espécies vegetais, como grande parte das do gênero Solanum, podem apresentar distintos morfos florais, que por sua vez podem influenciar em sua reprodução. Nesse contexto, o objetivo geral desse trabalho foi estudar a biologia da polinização de Solanum melongena L. (Solanaceae). Os objetivos específicos foram: 1) analisar a biologia e morfologia floral da espécie; 2) verificar o sistema reprodutivo e sexual da espécie; e 3) verificar a riqueza e o comportamento de seus visitantes florais. O estudo foi realizado em duas áreas de cultivo agrícola convencional, em Estiva Gerbi e Piracicaba, ambas no estado de São Paulo. Os visitantes florais foram observados entre fevereiro e junho de 2014. Os dados de morfometria floral foram coletados com auxílio de paquímetro manual e as diferenças entre as medidas foram testadas através do teste t. A estimativa da produção de pólen se deu através da contagem do número de grãos produzidos por antera. O número de grãos de pólen viáveis foi quantificado através da coloração citoplasmática, com a técnica do carmim acético. Para averiguar a relação entre a frequência dos polinizadores e a disponibilidade de pólen, foi calculado o coeficiente de correlação de Pearson (r). Para verificar a eficácia de diferentes polinizadores na formação de frutos e sementes da berinjela, foram selecionadas duas espécies de abelhas com comportamentos de forrageamento distintos: Apis mellifera, que não vibra e Exomalopsis diminuta, que vibra as anteras da flor para liberação do pólen. Análises de variância foram efetuadas para detecção de diferenças significativas entre os frutos formados por ambas espécies. O sistema reprodutivo foi analisado através da formação de tubos polínicos em diferentes horários após distintos tratamentos de polinização serem efetuados. Através da análise da morfometria floral, constatou-se diferença significativa entre os verticilos florais e reprodutivos dos diferentes morfos, caracterizando uma condição de polimorfismo na altura do estilete para S. melongena. As observações indicaram a presença de abelhas dos gêneros Bombus, Xylocopa, Apis, Trigona, Pseudaugochloropsis, Oxaea e Exomalopsis. Referente ao comportamento de cada espécie, notou-se uma variação tanto em relação à forma de coleta de pólen, quanto ao tempo de permanência na flor. Quanto ao sistema reprodutivo, notouse formação de tubos polínicos ao longo do estilete e os mesmos chegando aos óvulos apenas em flores longistilas, o que pode indicar uma condição andromonóica para a espécie em estudo. Conclui-se para Solanum melongena que a ação dos polinizadores é de grande importância para seu desenvolvimento, uma vez que, mesmo sendo autocompatível, a autopolinização espontânea não foi suficiente para uma efetiva fecundação de seus óvulos. Existem várias espécies que exercem papel de polinizadores, porém espécies que possuem o comportamento vibratório contribuem de maneira mais efetiva para o desenvolvimento desta cultura.