Mating system, mating behavior and the evolution thereof is the foundation of this study. More specifically the effect of inbreeding on the evolution of mating behavior is investigated. To this end the pollinating fig wasp, Platyscapa awekei, lends itself to inquiry about inbreeding and the effect on its behavior. A pollinating fig wasp female will lay her eggs inside a syconium, and all offspring will mate with each other. Interestingly the abovementioned pollinating wasp exhibits male dispersal, not commonly expected to occur in a haplodiploid species observed to inbreed frequently. Several theories attempt to explain the evolution of male dispersal in this case, but very little work has been done on the effect of inbreeding on the choice to disperse. In order to study the effects of inbreeding it was necessary to be able to measure the inbredness of individuals. For this reason I developed micro satellite markers both to determine the inbredness of individuals but also to derive parentage from offspring genotypes. With the inbreeding status in hand I had to correlate this with fitness measures in order to derive the effect of inbreeding on this species. Interestingly I found both inbreeding and outbreeding depression, with optimal fitness at some point between fully inbred and fully outbred status. I give some explanations for the occurrence of dispersal in this species but come to the conclusion that dispersal is merely part of a mixed mating system and that more detailed work need to be done to derive what the specific effect of dispersal is on fitness. / Dissertation (MSc(Agric))--University of Pretoria, 2009. / Genetics / unrestricted

The behaviour of sex allocation has been extensively studied in hymenopterans (ants, bees and wasps) as an adaptive trait with respect to intra-specific competition within the framework of kin selection theory. Mating in these organisms often takes place in patchy populations established by the offspring of a few foundresses. Typically, there is a bias in favour of female dispersal from these patches. Theory predicts that foundresses that oviposit alone will do best to produce just enough sons to mate all of their daughters so as to maximize the number of dispersing daughters, under conditions of what is referred to as Local Mate Competition (LMC) between brothers to mate their sisters. If foundresses co-found a patch with other foundresses, they are expected to invest more resources in sons insofar as opportunity to sire offspring with the daughters of the other foundresses presents itself. Among organisms with such a life histories are fig wasps, the insects that pollinate and lay their eggs in the flowers that grow inside young figs. There is thought to be strong selective pressure for foundresses to use information about clutch size differences in species where clutch sizes are small and low foundress numbers are frequently encountered. However, less rigorous modes of sex allocation are thought to suffice in species encountering intermediate foundress numbers. Theory thus predicts a positive relationship between the degree of structure within mating populations and the information utilized by foundresses with respect to intra-specific competition for resources and mating opportunities. This is being extensively tested across the diverse species range of fig wasps and their hosts with the larger objective in mind of contributing to a better understanding of the role of natural selection in accounting for variation observed of intra-specific behaviour. This dissertation reports on a study of the sex allocation behaviour of the pollinating fig wasp Platyscapa awekei, a species characterized by low foundress numbers and clutch size differences brought about by foundress competition over oviposition sites. Offspring collected from experimentally controlled twofoundress broods were fingerprinted using microsatellite genetic markers to assign maternity and work out clutch size differences. These data are used to test what information foundresses use when allocating sex. It is reported that foundresses appear to use information of clutch size differences in two foundress broods. This observation provides evidence of advanced information utilization in fig wasps. More generally, the findings add support to the hypothesis that natural selection can bring about subtle adaptive behaviour at the individual level, but simultaneously highlights the importance of accounting for the selective regime of the organism being studied when attempting to understand the role of natural selection in the evolution of fine scale adaptive traits. / Dissertation (MSc)--University of Pretoria, 2011. / Genetics / unrestricted