A distinct pattern of obligate mutualism exists between fig tree hosts and their pollinating fig wasps. Normally one section or subsection of fig tree hosts is associated with one fig wasp genus. In general, each species is pollinated by a specific fig wasp species. This led to the hypothesis that the fig wasp and fig tree lineages diverged simultaneously. African fig wasps pollinating hosts of the Galoglychia section frequently break the normal one fig wasp species-to-one host species ratio. The phylogeny for these species was reconstructed using three DNA segments and compared to the morphological classification of their Ficus hosts. Pollinator genera were monophyletic for all analyses, however, the relative positioning of genera was inconsistent. Analyses suggest frequent host jumps between fig trees and fig wasps. Fig wasps of the genus Alfonsiella that pollinate Ficus craterostoma, Ficus stuhlmannii and Ficus petersii are morphologically similar in South Africa. Based on host association, genetic differentiation for this group was investigated. Molecular data indicated that the pollinator of F. craterostoma is a good species, while the F. stuhlmannii and F. petersii pollinators were genetically indistinguishable. Based on molecular data and morphological re-evaluation, a new Alfonsiella species is described, Alfonsiella pipithiensis sp. n. A key to all described species of Alfonsiella is provided. In order to resolve the population genetic differentiation of pollinating fig wasp species in South Africa, Platyscapa awekei was used as a model species. A few studies indicate that pollinating fig wasps can disperse between 30 and 55 kilometers. However, a recent study on two P. awekei populations in South Africa reported an FST value of 0.011, indicating that pollinators disperse approximately ten times further. This study aims to confirm these results with more detailed sampling of populations. In addition, possible temporal differentiation was tested for the South African population. Six microsatellite loci were used to detect spatial and temporal genetic differentiation in seven populations (collected from 2004 to 2006) over a 340 kilometer range. Genetic differentiation between sampled populations was low (FST = 0.0055), however, the data suggest stronger temporal genetic isolation than spatial genetic isolation. / Dissertation (MSc (Genetics))--University of Pretoria, 2011. / Genetics / unrestricted

A striking variation in the behaviour of pollinating fig wasps (Agonidae) is the occurrence of male fighting in some species while in others it is completely absent. Fighting behaviour was investigated at two levels. Firstly, the variation in fighting behaviour between the species was used to examine factors that might cause the evolution thereof. Comparisons across species were done using phylogenetic regression. This method takes similarity due to phylogenetic constraints into account when data are compared. Kin selection theory implies that fighting is barred by the high degree of relatedness in competing males. We however find that the relatedness of the males do not have an influence on the evolution of fighting and this finding supports models suggesting that high LMC cancels benefits due to relatedness. Rather, that the only factor having a significant correlation with fighting is the release sex ratio. The release sex ratio and dispersal is also associated. Fighting and dispersal are not expected to have direct influence on each other and the association of both with the release sex ratio imply that this may be an indirect link between these two behaviours. A syndrome where fighting and dispersal is found together is in part explained by the release sex ratio. We conclude that the release sex ratio is the most likely cause of the evolution of fighting behaviour in pollinating fig wasps. The second part of this study deals with the proximal determinants causing fighting, in the males of the species Platyscapa awekei. We show that the sex ratio which, is less female biased than non-fighting pollinator species, rapidly becomes even less female biased as soon as both sexes becomes active. Numerous fights are fought by the males in the female limited environment. The activity of the wasps is shown to be regulated by the gaseous environment, which change from a high to a low CO2 concentration with the construction of an exit hole from the fig. The males of the species P. awekei are inactive, and do not engage in mating or fighting activities, in high CO2, contrasted to males of other species, which are active in this environment. P. awekei females rapidly release once the CO2 level is lowered and mating behaviour is only observed in this environment. The number of female to male encounters of every male decrease as the operational sex ratio becomes less female biased. Male fighting in this species is therefore expected due to the high sex ratio, which is enforced by the increase thereof. We conclude that the physical environment, in this species, affects the mating environment. The resultant reduction in the number of potential mating opportunities therefore escalates fighting between the males. / Dissertation (MSc)--University of Pretoria, 2008. / Genetics / unrestricted

This thesis explores the role mutualist pollinators and their symbionts play in the genetic structuring and speciation of their host plants along an elevational gradient in Papua New Guinea. Using the fig and fig-wasp mutualism as a model system, we employed high-throughput sequencing techniques to explore fine-scale population genomics of both fig and wasps along their elevational range. We found there to be clear lowland and highland clustering of tree populations along the gradient, often with a mid-elevation contact zone. In the case of the pollinating wasps, we retrieved the same clustering except in this case, the genetic difference between clusters was high enough as to consider them as separate species. This result supports evidence from other studies challenging the cospeciation paradigm of one wasp species per fig species. In addition, we explore ecological traits which may promote, or at least, maintain, reproductive isolation between fig (sub)species along with behavioural preference tests from pollinating wasps. In order to further investigate the mechanisms promoting wasp speciation along the gradient, we describe Wolbachia infection status as well as strain type. Wolbachia-induced cytoplasmic incompatibility (CI) is often invoked as a possible speciation agent since it can rapidly provoke and maintain reproductive isolation between otherwise freely interbreeding insect populations. Finally, we explore non-pollinating fig wasp (NPFW) diversity along the gradient for a subset of our focal species. Our study reveals that there is a tight relationship between NPFW diversity and host species, and a mid-elevation peak.