<p>Small populations are facing a particular risk of extinction due to a lack of appropriate genetic diversity and associated negative effects, factors dealt with in the discipline of conservation genetics. Many orchid species exhibit characteristics that make them a perfect study object in the scope of conservation genetics. The aim with this thesis was to investigate genetic structure at different levels in two orchid species <i>Gymnadenia conopsea</i>, geographically widespread, although diminishing and <i>G. odoratissima</i> with a long history of being rare. Microsatellite markers, developed in and used in studies of <i>G. conopsea</i> were also used in the study of <i>G. odoratissima</i>.</p><p>Populations of <i>G. conopsea</i> expressed high levels of genetic variation and a certain amount of gene flow, although investigated mating pattern in a small population indicated non-random mating among individuals, with the majority of pollen exchange between near neighbours, and noticeable levels of geitonogamous pollinations. Further a pronounced year to year variation in flowering frequency among individuals was found. </p><p>It was also discovered that flowering time variants (early and late) within the species <i>G. conopsea</i> were highly differentiated and seem to have had a more ancient historical separation than the separation between the two different species, <i>G. conopsea</i> and <i>G. odoratissima. </i></p><p>Levels of genetic variation in the rare congener, <i>G. odoratissima</i> differed between island and mainland populations where the more numerous island populations expressed larger levels of genetic variation and were less differentiated compared to the few remaining and genetically depauperated mainland populations.</p><p>Uppsala University Library, Box 510, 75120, Uppsala, Sweden </p>

All three essays in this thesis are concerned with the interrelation of family, gender and labour market outcomes. The first paper investigates family earnings mobility between parents and sons, and parents and daughters, highlighting the role of assortative mating. The results suggest that daughters are more mobile than sons. I also find that Sweden has a higher degree of mobility compared to the U.S., and that assortative mating is an important underlying channel for earnings transmission. The difference in mobility between the two countries does not inherently depend on factors affecting the marriage match. Moreover, adult economic outcomes are more dependent on family background for those at the lower end of the earnings distribution. The second study analyses the long-run effects of an increase in family size on the 1980-2005 labour market outcomes of Swedish men and women. The decision to have (more) children is dependent on current and future labour market prospects. I use the exogenous variations in the sex composition of the first two children to overcome this endogeneity problem. My findings suggest that having an additional child has a stronger negative impact on earnings than on participation. However, mothers experience a substantial but not complete long-term recovery in earnings. The third paper illustrates the difficulty in disentangling the underlying channels of intergenerational earnings persistence using a path analysis model. On closer examination, such a model has a potential shortcoming since the covariates are correlated to other unobserved factors. The results suggest that education is the most influential mechanism in the earnings transmission process, while IQ, mental ability and BMI are of secondary importance. However, education is sensitive to the inclusion of other covariates and the order in which these are entered into the equation. / At the time of the doctoral defense, the following papers were unpublished and had a status as follows: Paper 2: Manuscript. Paper 3: Manuscript.

This thesis relates modern speciation theory to the effects of sudden changes in the range and size of populations. Special reference is made to the climatic oscillations during the Quaternary ice ages. A meta-analysis of laboratory experiments showed that support for allopatric speciation is weak, especially for the peripatric type of allopatric speciation. Furthermore, factors traditionally believed to increase the likelihood of speciation have had little effect on the generation of reproductive isolation in speciation experiments. However, the method of testing reproductive isolation appeared important, in the sense that experimentally derived sister populations were likely to demonstrate reproductive isolation from each other but not from the unaffected mother population. Raw data from mating tests showed that the poor isolation between mother and daughter populations was an effect of asymmetric mate preferences towards males from the mother population. This suggests that peripatric speciation can be effective in generating reproductive isolation between sister populations. The proposed mechanism is that males become less attractive to females by losing certain secondary sexual traits during population bottlenecks, and that females shift their preferences towards other male traits. Support for this mode of speciation is found in the widespread bird genus Motacilla (wagtails). This genus is characterised by extensive plumage variation and contains a large number of widely distributed taxa in the northern parts of its distribution. This thesis shows that taxonomic diversity of wagtails is inversely related to complexity in song and to diversity in molecular and mitochondrial markers. The northern taxa seem to be descendants of southern populations, which were subjected to bottlenecks during expansions into re-opened habitats after the last ice age. The bottlenecks would not only reduce genetic diversity but also inhibit cultural transmission of song to the leading edge of colonisers, allowing sexual selection on other traits, such as plumage. Rapid plumage differentiation among wagtail taxa appears to be a recurrent process and has lead to convergent evolution, making the currently recognised species Motacilla flava (Yellow Wagtail) polyphyletic.

Genetic structuring is common in natural populations. It is important to identify and consider population structure when studying evolutionary processes. Recently, the discovery of genetic structuring in some lekking bird species has opened up new perspectives on our understanding of the evolution of lek mating systems. This thesis uses molecular data to identify patterns of broad and fine scale genetic structuring in the lekking white-bearded manakin Manacus manacus. Additionally, data on male mating success, female visiting patterns and behavioural, morphological and territorial characteristics of individual males are used to identify variables that may influence the distribution of matings in this species. Analysis of genetic divergence within the genus Manacus revealed genetic sub-structuring and limited gene flow between species/subspecies. There was no significant isolation by distance relationship. Factors such as physical barriers to gene flow may play a role in shaping the genetic structure of the bearded manakin genus. White-bearded manakin leks on Trinidad were composed of groups of related males. More than one such kin group existed on each lek. That related males gather in groups suggests that genetic structuring is not simply a consequence of limited dispersal. Active choices must take place by both residential and newly arrived birds. Female visits to, and matings with, males were non-random. Centrality of male display court was the only measured variable that consistently correlated with male mating success. More aggressive displays were made as the distance between courts decreased. There was no significant relationship between the number of aggressive displays made between males and relatedness levels. Males with high mating success spent more time in aggressive behaviours. In conclusion, white-bearded manakin lek formation and display court acquisition is likely to be influenced by genetic relatedness levels and male-male interactions. Centrality of court seemed important in mating success and may be an indicator of male dominance. However, a variety of other factors may also influence mating success and may be variable over time.

Small populations are facing a particular risk of extinction due to a lack of appropriate genetic diversity and associated negative effects, factors dealt with in the discipline of conservation genetics. Many orchid species exhibit characteristics that make them a perfect study object in the scope of conservation genetics. The aim with this thesis was to investigate genetic structure at different levels in two orchid species Gymnadenia conopsea, geographically widespread, although diminishing and G. odoratissima with a long history of being rare. Microsatellite markers, developed in and used in studies of G. conopsea were also used in the study of G. odoratissima. Populations of G. conopsea expressed high levels of genetic variation and a certain amount of gene flow, although investigated mating pattern in a small population indicated non-random mating among individuals, with the majority of pollen exchange between near neighbours, and noticeable levels of geitonogamous pollinations. Further a pronounced year to year variation in flowering frequency among individuals was found. It was also discovered that flowering time variants (early and late) within the species G. conopsea were highly differentiated and seem to have had a more ancient historical separation than the separation between the two different species, G. conopsea and G. odoratissima. Levels of genetic variation in the rare congener, G. odoratissima differed between island and mainland populations where the more numerous island populations expressed larger levels of genetic variation and were less differentiated compared to the few remaining and genetically depauperated mainland populations. Uppsala University Library, Box 510, 75120, Uppsala, Sweden

Competition over mating opportunities is a conspicuous characteristic of animal behaviour. In many butterfly species the males establish territories in places advantageous for encountering females. This thesis addresses questions about how territoriality has evolved and is maintained in butterflies. The studies have been conducted using the speckled wood butterfly, Pararge aegeria, as a model species. Males of P. aegeria are found in sunspots on the forest floor (paper I-V), on the lookout for females visiting the sunspots. However, males are only found in sunspots above a certain size (paper III). This behavior is maintained by a mating success advantage, where using large sunspots instead of small sunspots as perching areas generates a higher reproductive output (paper I). The mating success asymmetry is not explained by female choice or by a female preference for large sunspots per se (paper I, V), but rather the large sunspot facilitates visual performance of perching males and improves flight pursuit and interception of females (paper III). Winners of territorial contests gain sole ownership of large sunspot territories, while losers search for a new suitable sunspot territory (paper I, II &amp; IV) or use smaller, suboptimal sunspots as perching sites (paper II). Territorial contests between P. aegeria males are not settled due to an obvious morphological/physiological asymmetry (paper I). Rather, variation in resource value and motivational asymmetries are important for settling contests (paper IV). A majority of male-female interactions (paper V) and matings (paper I) are initiated by a perching male detecting and intercepting a flying female. Furthermore, females can affect their chances of being detected by a perching male by behaving more conspicuously (paper V). This thesis highlights the role of female behaviour, variation in resource value and motivation asymmetries to understand the evolution of territoriality in butterflies.

Estrogen stimulation of the medial amygdala (MEA) of the brain promotes male rat mating behavior. However, selective stimulation of either of the estrogen receptor subtypes found in the MEA (ERα or ERβ) does not support mating behavior. We tested the hypothesis that dual stimulation of ERα and ERβ is required to activate estrogen-dependant neural circuits in the MEA responsible for mating by local treatment of MEA with a combination of selective estrogenic agonists: propyl pyrazole triol (PPT, an ERα agonist ) and diarylpropionitrile (DPN, an ERβ agonist) administered to castrated, DHT maintained male rats. Estradiol (E2) or cholesterol (Chol) MEA implants served as positive and negative controls respectively. The animals receiving a mixture of PPT and DPN into the MEA displayed higher levels of mating behavior than the Chol treated animals but lower levels of mating behavior than the E2 treated animals.

Within social insect colonies, sterile workers are responsible for brood care, while queens are the primary egg-layers. These reproductive caste differences are often accompanied by pronounced morphological distinctions. Queen and worker phenotypic differences are particularly remarkable considering caste is environmentally, rather than genetically, determined. Environmental caste determination can produce intralocus genetic conflict between castes, particularly when homologous traits are highly dimorphic. Therefore, when studying the evolution of social insect caste dimorphism, one must consider the genetic architecture underlying phenotypic expression as well as the selective pressures that have shaped caste morphology. This dissertation presents the results of four studies that investigated factors affecting caste morphology in the social wasp Vespula maculifrons. The first two studies focused on identifying queen morphological traits that were positively associated with queen fitness and would therefore be subject to selection. Queen length, specifically gaster length, was positively associated with overwintering survival and was consistently associated with mating success. Both of these findings suggest that queen gaster length is under selection during two life-history events, mating and overwintering, in which workers do not participate. These findings provide empirical support for the adaptive evolution of a caste dimorphic trait. The third and fourth studies used classical quantitative genetic and morphological analyses to examine the genetic architecture underlying caste dimorphism in V. maculifrons. I determined which traits were under caste-specific selection by analyzing trait allometries and the levels of genetic control, variation, and dimorphism of traits between castes. Little genetic variation for morphological trait size was detected for most worker and queen traits, suggesting a strong influence of environment on phenotypic variation. Additionally, analyses of trait allometries indicated that several queen traits (mass, thorax width and length) were under queen-specific selection. The relationship between thorax length, gaster length, and overall body size is further evidence of selection on length in queens. Overall, these studies provide evidence for the importance of queen-specific selection in the evolution of caste dimorphism. When placed in the broader context of caste evolution, they point to the importance of life-history in shaping the genetic architecture underlying caste dimorphism.

Natural populations exhibit a non-random mating behavior and it is assumed that mate preferences causing the non-random mating behavior play a role in sympatric speciation. In my thesis, I have proposed a new model of a mate preference that is based on ecological performance and I have named it fitness-based mating. Individuals that express this mate preference choose primarily fit partners. Fitness-based mating is modelled for haploid, diallelic populations. Individuals are distributed across two niches, and genomes are simplified to two loci. The first locus is subject to natural selection, and the second-locus genotype gives the strength of the mate preference. The population is separated into females and males, among which only females exhibit the mate preference. Ecological selection acts on both sexes alike. With the model I have investigated how female choosiness based on direct advantages offered by their partners can cause and maintain a polymorphic population. Fitness-based mating is an evolutionary successful mating strategy. It spreads in a population due to its amplifying effect on the reproductive success and on the attractiveness of its carriers. A polymorphism arises naturally in the model. The emergence of a stable polymorphism of traits underlying ecological selection is of special interest, because a polymorphism can be a precursor of speciation.

The Mercurialis annua L. (Euphorbiaceae) species complex comprises a group of closely related lineages that present a wide range of sexual-systems, making it a valuable model for the study of plant sexual-system evolution. Within this polyploid complex, diploid populations are dioecious, and polyploid populations either monoecious or androdioecious (males coexist with functional hermaphrodites). The primary aim of this thesis was to use patterns of genetic diversity to elucidate the evolutionary origin and maintenance of the sexual-system diversity in M. annua. The phylogeny of the M. annua complex was reconstructed using chloroplast and ITS DNA sequence. This, in conjunction with morphometric analysis, showed that both hexaploid M. annua, and a novel species from the Canary Islands (newly described here as Mercurialis canariensis), were allopolyploid in origin. Such an origin for hexaploid M. annua suggests that androdioecy may have been able to arise in this group as a consequence of hybridisation between a monoecious lineage, tetraploid M. annua, and a dioecious lineage, M. huetii. Artificial crosses were used to show that hexaploid M. annua has disomic marker inheritance, and a statistical approach was developed to quantify genetic diversity and differentiation in polyploids with disomic inheritance. Strong gradients in genetic (allozyme) diversity at a pan-European scale were used to infer the existence of separate glacial refugia for dioecious and monoecious races of M. annua, at the eastern and western ends of the Mediterranean basin, respectively. A metapopulation model had previously been proposed to explain the ecological maintenance of androdioecy in M. annua. Here, population-level patterns of genetic diversity were used as an indirect test of this model. The discovery of lower within-population diversity, and of greater genetic differentiation between populations, for monoecious populations than for androdioecious populations was consistent with the metapopulation model, and suggests that androdioecy is maintained by the occurrence of regular local extinction.