Thesis (Ph. D.)--University of Queensland, 2003. / Includes bibliographical references.

Thesis (doctoral)--Universität St. Gallen, 1998.

published_or_final_version / Statistics and Actuarial Science / Doctoral / Doctor of Philosophy

According to Darwin, any inheritable traits that enhance fitness (i.e. survival and reproductive success) would be adaptive in a given environment, and therefore subject to natural selection. Some traits that enhance reproductive success but not necessarily survival may, however, evolve through the process of sexual selection. The importance of sexual selection has been intensively studied in “higher animals” birds, mammals and insects but has largely been neglected in “lower animals” such as gastropods. Using two mangrove snails, Littoraria ardouiniana HEUDE 1885 and L. melanostoma GRAY 1839 (Littorinidae) as model species, this thesis documents their various reproductive traits and the occurrence of sexual selection, in an attempt to understand how these animals optimize their fitness. Being one of a few gastropod families that live closely associated with mangrove habitats, various adaptive reproductive traits are likely to have evolved in the genus Littoraria. The two Littoraria species exhibited several, contrasting, reproductive traits (e.g. reproductive mode; length of reproductive season; seasonal fecundity and egg- or larvae-releasing rate), which may represent species-specific strategies to optimize reproductive success. Both species adopted mucus trail following as a mate-searching strategy; with males being able to discriminate the trails laid by conspecific females and trail orientation during the mating season. Since these two snails mate in the complex habitat of mangrove tree canopies, incorporating some cue into mucus trails to aid mate recognition would increase potential encounter rates and hence reproductive success. 1D proteomic techniques identified two potential pheromones in the trail mucus of female L. ardouiniana, but further investigations are needed to confirm their possible role as sex pheromones. Evidence for sexual selection was found in L. ardouiniana through male mate choice and male-male competition. Large male L. ardouiniana showed a preference for mucus trails laid by large (= more fecund) females, but this preference was not seen in small males, suggesting a size-based male mate preference. Males of this species also mated with larger females for a longer duration and they showed physical aggression (i.e. they pushed each other) when they encountered a female. These sexual selection mechanisms may drive size-assortative mating patterns in littorinid species and in other animals. Conversely, L. melanostoma exhibited no obvious male mate preference or male aggression. Such differences in sexual selection patterns from L. ardouiniana were proposed to be a result of differences in operational sex ratio and variation in female quality. As many gastropods show similar mating behaviour to littorinids (i.e. trail following, shell mounting and copulation), sexual selection may operate in a comparable manner in other gastropods. By revealing the complexity of sex roles of males and females (e.g. the mutual occurrence of male mate choice and male-male competition) and condition-dependent male mate preference in these mangrove snails, this thesis has contributed to a missing link between sexual selection and the “lower animals” and provides new insights into the operation of sexual selection in animals. / HKU 3 Minute Thesis Award, Champion (2012) / published_or_final_version / Biological Sciences / Doctoral / Doctor of Philosophy

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published_or_final_version / Statistics / Master / Master of Philosophy

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Problem: To compete effectively in today’s global market, organizations are eager to expand their operations abroad. Entering a partnership accounts as a preferred way of doing this. In order to be allowed to participate in many important markets, corporations must recognize the influence of cultural orientations other than their own. In many cases it appears that this is however neglected, considering that up to two out of three partnerships ends in dissolution. Causes related to the cultural aspect of a relationship are often mentioned to form the root of the problem. We noticed that a vast number of studies have focused on how culture affects single organizations, fewer studies however focused on how partnerships are affected by cultural aspects. And even fewer studies have tried to decipher the role that cultural compatibility has prior to entering a partnership. More so, throughout our extensive literature review, we have noticed that there has not been obtained a comprehensive understanding of what cultural compatibility entails. Purpose: The intentions of our research are twofold: first, we have theoretically derived a framework that allows a comprehensive understanding of cultural compatibility as well as its influence on alliance performance, and second, we have explored how this theoretically derived framework is reflected in practice. Method: To achieve the purpose of this study we completed a qualitative, exploratory research including five case studies and five interviews/consults. The case studies were well selected based on requirements such as industry significance and the implication of a high level of cultural diversity. Conclusions: The major conclusion to our research indicates that cultural compatibility is not necessarily a requirement prior to entering a relationship, but unveils to be moreover a foundation that partnering firms should strive for in the early stages of their coalition. Additionally, we have obtained many valuable insights, yet utmost we have experienced that the subject is extremely complex, and that further research on the topic as well as the framework is indispensable to further justify our findings.

Restored plant populations frequently fail to establish or don’t persist over short to intermediate periods of time. These unsuccessful restoration attempts may be the result of strong selection and a high degree of maladaptation within restored populations. There are various potential evolutionary causes of maladaptation within restored systems, which may ultimately lead to extirpation. Here, I investigated whether current restoration practises systematically lead to stronger selection and a greater magnitude of maladaptation, by comparing restored prairie populations of Monarda fistulosa to naturally occurring populations. Phenotypic selection and maladaptation analyses were conducted on nine ecologically important traits in three restored and three natural tall grass prairie populations. Significant differences in selection and maladaptation were detected among the six study populations; however there was no significant difference between restored and natural populations. The lack of difference may indicate that the restored populations are well adapted to their environment or that natural populations are less well adapted than assumed.