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Montagnea arenaria [Hymenogastrales, Basidiomycota] , adapted to desert and xeric habitats, is morphologically and phenotypically variable. Species have been described on the basis of macromorphology and spore shape and size. This study was initiated to investigate populations of M. arenaria from Namibia in Africa and the Southwestern United States. It was hypothesized that biological species would exist in the widely separated populations. Spores from single sporocarps were germinated, single spore isolates were obtained and selfed to obtain mating types. On transfer, clamp connections were not maintained and mating patterns could not be achieved. Nuclear staining revealed multinuclei in the hyphae of both single spore isolates and compatible crosses. Spores were stained and found to have either 1 or 2 nuclei, but only four sterigmate basidia were observed. Limited partial compatibility was achieved and in some cases clamp connections formed within and between crosses from the two continents. Genomic DNA was extracted from old herbarium specimens. The ITS1, 5.8S, and ITS4 regions of nuclear ribosomal DNA were amplified and sequenced directly. Phylogenetic analysis using PAUP was performed. The hypothesis that Montagnea would form different biological species based on continental separation was rejected. In fact, the complex of isolates from widely varying locations not only had partial compatibility, but the variation in ITS sequences among widely distributed collections was relatively low. Lastly, no correlation between sporocarp size and gene flow among specimens from a wide variety of habitats was found. It appears that M. arenaria is a single, highly variable, widely distributed species. / Master of Science

In the first longterm field study of the fossa, mean adult body mass measured was, in males, 7.4 kg (n=17, s.d.=1.2), and, in females, 6.1 kg (n=11 females, s.d.=0.6). Sexual size dimorphism was most marked in canine width. 376 scats yielded 554 prey items, of which the majority were lemurs (>50%)m, tenrecs and snakes. Incidence of prey in scats correlated positively with abundance. Scat composition varied with season, but not with year nor gender of fossa. Sexual dimorphism could not therefore be explained as niche separation. Home ranges were, for two males, 22.74 km² and 26.20 km², and for two females, 12.69 km² and 7.84 km². These, and incomplete ranges of six others, overlapped between males but not females, and were larger in the dry season than in the wet season. Censuses and radio-tracking generated consistent population density estimates, averaging 0.17 adults per km², substantially lower than predicted from body size, and indicating that even Madagascar's largest reserve may not hold a viable population of fossas. The unique mating system resembled a lek: females mated with multiple males on traditional sites. One female occupied a site at a time, for up to one week. The system may benefit species with low population density, by increasing mate choice for females and facilitating mate location for males. It may also reduce sexual harassment of oestrous females. Males fought at the sites, but no size-related advantage in male mating success was observed. A different mating system was predicted from the home range data. The first discovery was made of transient masculinization of a female mammal. Juvenile female fossas (n=8) exhibited an enlarged, spinescent clitoris supported by an os clitoridis, and a pigmented secretion that in adults was confined to males. Masculinization was hypothesized to reduce sexual harassment of young females.

Reproductive studies in invasive plants are necessary for an understanding of their potential to establish and spread in foreign environments. Elaeagnus umbellata Thunb. (autumn olive) is an invasive woody shrub that flowers early in the spring and is often noted for its abundant fruit set. This study examined the reproductive biology of E. umbellata in Illinois, where it is highly invasive. Hand-pollination experiments were performed to determine the breeding system of E. umbellata, and floral visitors were collected to determine its pollinators. Experiments showed that E. umbellata is a predominantly outcrossing species with a self-incompatible breeding system. However, individual variation was detected in several reproductive characteristics. Pollen tube analyses revealed that a small percentage of individuals allow successful self-pollen tube growth, and self-fruit set resulting from automatic self-pollination (autogamy) was relatively high in a few plants. Automatic self-pollination is possible because the male and female parts of flowers mature sychronously, but the likelihood of autogamy may vary among individuals due to variability in the spatial separation of male and female parts (herkogamy). Variability in the incompatibility system and the level of herkogamy may impact the outcrossing rates and reproductive success of individuals. The majority of floral visitors to E. umbellata were generalist pollinators. Frequently visiting bees included small and large species such as native Andrena spp., Augochlorella aurata, Bombus spp., Ceratina calcarata, Xylocopa virginica, and the introduced Apis mellifera. Bombylius major (large bee fly) and the moth Mythimna unipuncta (armyworm) were also frequent visitors. Most of the above insect taxa are pollinators of E. umbellata based on analysis of pollen on insect bodies. E. umbellata is likely to achieve its abundant fruit set where these common pollinators and other E. umbellata are present. However, in my study sites, many individuals experienced low fruit set on branches that were open to pollinator visitation, suggesting pollen limitation may be common in some years and at certain sites. The discovery of autogamous individuals demonstrates that some E. umbellata individuals may be able to establish and spread even when mates or pollinators are limiting.

Social organization of a species may impact behavior, reproductive ecology, mating system, population genetic structure and overall fitness. A spectrum of sociality exists from solitary individuals to aggregations to integrated, highly related groups. A large body of knowledge exists for sociality and life-history characteristics of ground-dwelling sciurids, including several overarching models to explain the evolution of sociality. These models predict round-tailed ground squirrels (Xerospermophilus tereticaudus) to be solitary based on small body size (~125g), relatively long period of activity (January-June) and a short period of adult-juvenile overlap. However, previous behavioral observations suggest round-tailed ground squirrels have a clustered matrilineal structure with a suite of social behaviors, suggesting that they may represent a unique outlier in ground squirrel sociality models. Within the population of round-tailed ground squirrels at the Casa Grande Ruins National Monument in Coolidge, Arizona, USA, rates of amicable and agonistic interactions between adults were low, with no relationship between relatedness of individuals and rates of social interactions. No population substructure was evident with Bayesian analyses, global or pairwise F(ST) values, and average relatedness among females did not differ from males. Contrary to previous behavioral studies, round-tailed ground squirrels did not have high levels of social behavior, nor did they form significant genetic subpopulation structuring. The active season of round-tailed ground squirrels closely followed patterns of precipitation and peak resource availability. Body mass differed between males and females, across years, and within seasons. Males were heavier than females at emergence, prior to mating and pre-hibernation, but not when females began gestation. Emergence of litters and litter size are related to amount and timing of winter rainfall. Foraging and vigilance behaviors compose 64-66% of the activity budget, but differ in that males spend a greater proportion of time foraging, whereas females spend a greater proportion of time vigilant. Round-tailed ground-squirrels have a polygynandrous mating system. Polygyny was evident in 2004, 2005, and 2006, and multiple paternity occurred in the majority of litters with 2.5 sires/litter; litter size was positively correlated with the number of sires. These findings support predictions generated by sociality models for ground-dwelling squirrels.

In species where males do not provide immediate benefits to females in the form of resources or parental care to offspring, adaptive mate choice may be maintained by selection because preferred males sire offspring that are genetically superior. I test the hypothesis that female mating preferences result in enhanced performance of their larvae, owing to genetic variation among sires in two species of red-eyed treefrogs. This variation in males may be manifested as body size or in advertisement call parameters. I examined natural pairing patterns and found that both species display a size-based mating pattern with substantial seasonal effects. In lean years, females mate with males that are larger on average, yet females also seem to favor a constant size ratio of the male relative to her body size. I documented significant call trait variation both within and among males and have evidence to support size-related call traits as indicators of mating success for some properties. Finally, I provide evidence for a pronounced effect of sire size on offspring traits, most notably upon hatching that may have significant post-metamorphic fitness benefits. My study provides data on the basis of female choice and may provide a link between female preference for male traits and enhanced offspring performance by larvae sired by preferred males in the evolution of anuran mating systems.

By performing a comparative analysis and using phylogenetic relationships of the Cervidaefamily this study aimed to address whether or not sexual selection may play a role in the extinctionof species by making species more vulnerable to extinction. The role of sexual selection in makingspecies more vulnerable to extinction is largely unexplored, and several factors such as ecologicaland life history traits may increase the risk of extinction.In all species of the family Cervidae (Gilbert et al. 2006, Geist 1998,Groves and Grubb2011,Meijaardand Groves2004,Price et al. 2005, Goss 1983) sexually selected characters plays amain role in determining species status and thus potentially their probability of extinction. In thisstudy the intensity of sexual selection (measured as sexual size dimorphism, antler size and matingsystem) and the rate of extinction (IUCN classification and anthropogenic effect) were counted asfactors to determine the role of sexual selection intensity in both species-rich and species-poorclades.By using the programme MESQUITE and phylogenetic trees, the results show an associationbetween species with larger body size and dimorphism, living in open habitats and having largerantler size expanded to more than three tines; such species are mostly non-territorial and formharems during the rutting season. The small species are territorial, live in closed habitats, aremonomorphic and have small antler size limited to two tines or less. Moreover species that aremore subjected to habitat degradation and anthropogenic effects tend to become smaller in size.Extinction risk for the species-rich clades with small sized, territorial and small antler sizedspecies is lower than for those consisting of species with larger antler size, larger body size, livingin open habitats and using harems as mating system.To sum up, the intensity of sexual selection in larger species in deer family put them in risk ofextinction; but on the other site, small species are more adapted to the environment by choosingdifferent strategy in mating system, and reducing antler and body size thus diminishing theextinction risk.

Many species have suffered severe range contractions as a result of human impacts, and require careful management if they are to persist. An understanding of the ecology, population structure and mating system is important for the conservation of these endangered species. Translocation has become a widely used tool in the conservation of threatened species; however, without proper planning and monitoring, many programmes end in failure. The bridled nailtail wallaby is one of the most endangered macropods in Australia, having suffered an extensive range contraction from the semi-arid region of eastern Australia to a single remnant population of ~ 500 animals at Taunton National Park in Queensland. In 1996, a translocated population of bridled nailtail wallabies was established at Idalia National Park, on the western edge of the former range of this species. The aims of this study were to: 1) determine the factors underlying variation in reproductive success among animals released at Idalia; 2) investigate the effects of a range decline on the genetic variation and population structure of the remnant population at Taunton; 3) assess the impact of captive breeding and translocation on the genetic diversity and structure of the established population at Idalia; and 4) investigate male and female mating strategies in this species. Chapter two investigated reproductive success among males released at Idalia National Park. The bridled nailtail wallaby is a sexually dimorphic, polygynous species and there is a large amount of variation in male reproductive success. Animals of different origin were released, including animals bred in captivity off the park, animals bred on-site in enclosures, and wild-caught animals from the remnant population that were moved directly to Idalia. There was significant variation in reproductive success among males released, but the origin of those animals did not explain this variation. Instead, large males were the most reproductively successful regardless of origin. Survival probability and release location were also important factors. This study highlighted the importance of considering mating system when choosing animals for translocation and suggests that, for polygynous species, a greater proportion of females and males of high breeding potential should be released. In Chapter three I investigated the genetic diversity and fine-scale genetic structure of the remnant population at Taunton. This last remaining population has been isolated for at least 60 years, corresponding to 30 generations for this species. Animals are patchily distributed in assemblages of different size that cover ~ 10% of suitable habitat on the park. Genetic diversity was surprisingly high within the population remnant and this species showed one of the highest levels of heterozygosity and allelic diversity of any macropod. The three sub-populations of animals sampled over 10 km were significantly differentiated, and fine-scale spatial genetic structure was also observed within a continuous sub-population of animals covering just 750 ha. Females were more related to each other than expected from random, whereas males were less related to each other than expected. Fine-scale genetic structure was observed among females but not males, providing evidence for female philopatry and male-biased dispersal. I suggest that fine-scale population structure and restricted gene flow among females but not males may maintain genetic diversity in this remnant population. Chapter four assessed the effect of translocation of animals of different origin on genetic diversity in bridled nailtail wallabies. Both wild-caught and captive-bred animals were initially released, but subsequent releases consisted of captive-bred animals only. In this study, I compared genetic diversity of released animals to animals sampled in the remnant population. Heterozygosity did not differ between the remnant and translocated population, however allelic diversity was significantly reduced among all groups released. Animals bred in captivity were significantly differentiated from the source population, whereas animals moved directly from Taunton were not. Releasing more captive-bred animals into the population after the initial release resulted in a decline in overall heterozygosity and allelic diversity. This study highlights the importance of sourcing animals directly from remnant populations in order to maintain genetic diversity and minimize genetic drift between source and recipient populations. The bridled nailtail wallaby has a polygynous mating system and reproductive success is skewed toward large males. However unlike most polygynous, sexually dimorphic macropods, the bridled nailtail wallaby is highly solitary; animals only associate to breed and males do not form stable dominance hierarchies. In Chapter five I investigated behavioural strategies used by males to secure matings, and mate choice among females. I found that males of different size adopted different mating strategies. Large males spent more time guarding females against other males and maintaining contact with them, whereas smaller males spent less time with guarded females in order to search for other females in oestrus. Females also preferred larger males and were more likely to engage in mate chases if there was a large number of males within the group.

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

In the majority of sexual eukaryotes, mitochondria are inherited predominantly from a single, usually the female, parent Like the majority of higher plants and animals, the pathogenic yeast Cryptococcus neoformans has two mating types (sexes), however, these two sexes are morphologically similar. In this study, I examined the distribution of the mating types and how mating types influence the inheritance of mitochondria in C. neoformans. My survey of mating type alleles in 358 isolates collected from four geographic areas in the US showed a biased distribution of mating type alleles with most isolates containing mating type a alleles. To characterize the role of mating type locus on mitochondrial inheritance, I constructed two pairs of congenic strains that differed only at the mitochondrial genome and mating type locus. Mating between these two pairs of strains demonstrated that uniparental inheritance in C. neoformans was controlled by the mating type locus and progeny predominantly inherited mitochondria from the mating type a parent. Specifically, we identified two genes within the mating type locus, SXIIa in mating type a strain and SXI2a in mating type a strain, that control mitochondrial inheritance. Disruption of these two genes resulted in biparental mitochondrial inheritance in sexual crosses. These two genes are the first ones identified capable of controlling uniparental mitochondrial inheritance in any organism. In addition, we determined that the deletion of the SXIIa gene enhanced the spread of mitochondrial introns in sexual crosses. This discovery is consistent with the hypothesis that uniparental lnheritance might have evolved to prevent the spread of selfish cytoplasmic elements. / Thesis / Doctor of Philosophy (PhD)