O dimorfismo sexual nas espécies pode surgir a partir da seleção decorrente dos diferentes sistemas reprodutivos. Estudos comportamentais de espécies neotropicais são raros e pouco se sabe sobe as espécies brasileiras. Neste estudo, foram descritos o comportamento de três espécies neotropicais que ocorrem no Cerrado brasileiro: Acanthagrion truncatum, Argia reclusa (Coenagrionidae) e Heaterina rosea (Calopterygidae). Também foi evidenciado o dimorfismo sexual nestas espécies e investigou-se a partir de observações comportamentais, como o dimorfismo se desenvolve em espécies com diferentes táticas reprodutivas. Com os resultados obtidos, vemos que em espécies territoriais os machos são maiores do que as fêmeas, enquanto em espécies não-territoriais as fêmeas são maiores do que os machos. Sugere-se que, diferentemente de outros estudos, em Zygoptera o tipo de sistema reprodutivo pode determinar o dimorfismo sexual. / Sexual size dimorphism (SSD) can in some species result from the selection acting through different mating systems. Behavioral studies of neotropical species are rare, and few is known about the brazilian species. In this study, we described the behavior of three neotropical species that occur in the brazilian neotropical savannah: Acanthagrion truncatum, Argia reclusa (Coenagrionidae) and Heaterina rosea (Calopterygidae). We show the SSD in these species and investigates through behavioral observations, how SSD develops in species with different mating tactics. With our results, we can see that in territorial species the males are larger than females, while in non-territorial species the females are larger than males. We suggest that, unlike other studies, in Zygoptera the kind of mating system adopted by males may determinate the SSD in a species.

O dimorfismo sexual nas espécies pode surgir a partir da seleção decorrente dos diferentes sistemas reprodutivos. Estudos comportamentais de espécies neotropicais são raros e pouco se sabe sobe as espécies brasileiras. Neste estudo, foram descritos o comportamento de três espécies neotropicais que ocorrem no Cerrado brasileiro: Acanthagrion truncatum, Argia reclusa (Coenagrionidae) e Heaterina rosea (Calopterygidae). Também foi evidenciado o dimorfismo sexual nestas espécies e investigou-se a partir de observações comportamentais, como o dimorfismo se desenvolve em espécies com diferentes táticas reprodutivas. Com os resultados obtidos, vemos que em espécies territoriais os machos são maiores do que as fêmeas, enquanto em espécies não-territoriais as fêmeas são maiores do que os machos. Sugere-se que, diferentemente de outros estudos, em Zygoptera o tipo de sistema reprodutivo pode determinar o dimorfismo sexual. / Sexual size dimorphism (SSD) can in some species result from the selection acting through different mating systems. Behavioral studies of neotropical species are rare, and few is known about the brazilian species. In this study, we described the behavior of three neotropical species that occur in the brazilian neotropical savannah: Acanthagrion truncatum, Argia reclusa (Coenagrionidae) and Heaterina rosea (Calopterygidae). We show the SSD in these species and investigates through behavioral observations, how SSD develops in species with different mating tactics. With our results, we can see that in territorial species the males are larger than females, while in non-territorial species the females are larger than males. We suggest that, unlike other studies, in Zygoptera the kind of mating system adopted by males may determinate the SSD in a species.

Genetic changes likely occur in wild fish populations as a consequence of interactions with cultured fish, but to what extent do those changes threaten the maintenance of natural genetic diversity and population viability? Following a review and categorization of numerous processes suspected of being agents of post-release genetic change in recipient wild populations (Chapter 1), I focus on risks relating to the magnitude and duration of releases -- but with a twist. That is, I assume that the mean fitness of released, cultured individuals does not differ from that of the recipient natural population. Throughout, attention is devoted to potential post-release changes in inbreeding (NeI) and variance (NeV) effective population sizes -- indicators of expected rates of population-level change in inbreeding and drift variance, respectively. The reductive effect that large-scale releases exert on NeI in recipient populations can be significant. The effect is shown to be a threshold process (Chapter 2) and thus suggestive of an approach for determining risk-adverse stocking (or release) rates. This approach is utilized in Chapter 3, which describes genetic recommendations for an incipient marine stocking program. Several discordant contemporary NeI models are examined mathematically and by computer simulation (Chapter 4). I show that certain published results pertaining to the effect of multiple paternity on NeI are erroneous; a general model is described which accounts for inbreeding and relatedness in and among parents. That model is utilized in an empirical study of gene correlation in a hatchery cohort (Chapter 5). Propagation-related causes of reductions in NeI are also investigated in this cohort. Finally, extending mutational meltdown theory to accommodate fluctuating population sizes and recessive selective effects, I show that when large reductions in NeV occur (such as those that accompany admixtures of cultured and wild fish), the expected time to population inviability is significantly reduced (Chapter 6). Although a more comprehensive theoretical approach is needed, a precautionary inference may be drawn -- aquaculture-induced reductions in Ne, even though they may be transient, can lead to adverse genetic impacts. Avoidance of Ne-reductions cannot be accomplished, in a practical sense, without considering the stocking or release rates of cultured fish.

In a territorial population of pronghorn from Antelope Island, UT, interaction between male dominance and territory defense was examined. High-ranking males were more likely to defend territories. Closely ranked animals engaged in more dominance interactions than distantly ranked individuals, and middle-ranked animals were involved in disproportionately more interactions than either high- or low-ranking animals. Large males possessed large horns and prongs as well as small cheek patches. Results from a factor analysis suggested that large males defended territories with a high density of sage. However, in this study, we did not observe pronghorn feed on sage during the territorial season. Though male pronghorn practiced resource defense polygyny, large, dominant males did not defend territories with a high density of green vegetation or green forbs. Large males appeared to defend territories with low visibility. In 1996, intruders entered areas that contained females throughout the territorial season. During the next year, highly visible, small territories received the most intrusions. Together, these observations suggest defense of tactical locations. Defending a tactical location may help females avoid harassment and males hide the presence of females. Different populations of pronghorn practice different mating systems. To understand this variation, we examined the behavior patterns/rates of individual territorial and bachelor males. The highest rates of activity and behavior patterns occurred in March/April and in September. Territorial males cheek rubbed at a higher rate than bachelors. Territorial males were more active and SPUD (sniff, paw, urinate, and defecate) marked at a higher rate than bachelor males in 1996. After the formation of a bachelor herd in 1997, bachelor males showed higher rates of male-male interactions than territorial males. Territorial males maintained the same activity and behavioral rates in the presence and absence of females. Dispersion pattern of scent marks was more clumped in the presence of females. These findings suggest cheek rubs function more as a space-claiming behavior while SPUD marking is more strongly associated with male-male interactions. Comparison to male behavior in nonterritorial populations indicates that the behavioral mechanisms are present in all populations to accommodate shifts in social systems.

<p> </p> <p>The degree of self-fertilization in a population determines levels of genetic variation and high selfing rates could thus limit future adaptive potential. Theory predicts that intermediate selfing rates should not persist, yet many plants exhibit mixed mating. Cleistogamy is a floral heteromorphism where individuals produce both showy potentially outcrossing chasmogamous flowers and closed obligately selfing cleistogamous flowers. Reproduction via cleistogamous flowers is thought to be beneficial because of their greater energetic economy compared to chasmogamous flowers but can be costly if selfing leads to inbreeding depression or accelerates the fixation of deleterious mutations within populations. Cleistogamy has evolved independently multiple times and can be used to study the maintenance of adaptive mixed mating. To investigate this, I estimated the costs and benefits of selfing in three populations of <em>Ruellia humilis </em>Nutt (Acanthaceae) in greenhouse common garden experiments. To quantify the costs, I performed hand pollinations and quantified fitness components of progeny resulting from selfing and outcrossing within- and between-populations. To quantify the relative energetic advantage of cleistogamous flowers, I measured dry flower mass, fertility, seed number per fruit, and pollen-ovule ratios of both types of flowers. I found negative cumulative inbreeding depression in all populations, indicative of selfed progeny outperforming outcrossed progeny. While the fitness consequences of between population outcrossing ranged from heterosis to outbreeding depression. When looking at the energetic benefits of selfing, I found that the cost of reproduction via cleistogamous flowers was between 3 and 14-fold less than the cost for outcrossing flowers. Finally, I combined data on inbreeding depression and the energetic costs of reproduction and found that chasmogamous flowers of <em>R. humilis </em>must provide between a 3 to a 45-fold fitness advantage to be maintained, the magnitude of which was dependent upon maternal population. Overall, I conclude that none of the existing hypotheses are sufficient enough to provide the selective advantage needed to explain the persistence of chasmogamous flowers in <em>R. humilis</em>. Without any supported explanations for the maintenance of mixed mating, the exploration of genetic constraints on the loss of chasmogamous flowers could solve this long-standing mystery. </p>

在族群遺傳學中已知有許多因子影響基因型與對偶基因頻率，族群的交配方式即為其中之一。例如，哈溫平衡定律即指族群進行隨機交配，而芮特平衡定律所描述之自交系理論指的是族群進行了某種特定型式的非隨機交配。本文將以往討論過或未討論過之族群基因型頻率會達到哈溫比例及芮特比例的交配系統做一整合性研究。族群基因型頻率會達到哈溫比例或芮特比例之交配系統的整體架構將根據交配群體中雙親二子群體的交配行為、基因型頻率是否在哈溫比例及是否相同、對偶基因頻率是否相同來建立。整體架構中的每一構造點所對應的交配系統將被找出或證明不存在，若存在則會進一步討論其特性。 目　錄 摘要………………………………………………………………….. I ABSTRACT………………………………………………………… II 圖表目錄…………………………………………………………….. VII 第一章 緒論……………………………………………………….. 1 第二章 族群達到Hardy-Weinberg比例及Wright比例的交配系統之整體架構………………………………………….. 3 第三章 族群達到Hardy-Weinberg比例之隨機交配系統……... 6 3.1 基本定義與原理………………………………………………………. 6 3.1.1 基因型頻率與對偶基因頻率…………………………………… 6 3.1.2 隨機交配與非隨機交配………………………………………… 7 3.1.3 基因型隨機交配會導致配子隨機結合原理…………………... 7 3.1.4 平衡族群的交配系統之特性…………………………………… 8 3.2 雌雄二次群體之基因型頻率在相同的Hardy-Weinberg比例且其子代群體基因型頻率會達到Hardy-Weinberg比例的隨機交配系統 ………………………………………………………………… 9 3.3 雌雄二次群體之基因型頻率在不同的Hardy-Weinberg比例的隨機交配系統 其子代群體基因型頻率不會達到Hardy-Weinberg比例……………………………………………………….. 10 3.4 雌雄二次群體之基因型頻率不在Hardy-Weinberg比例但基因型及對偶基因頻率皆相同下其子代群體基因型頻率會達到Hardy-Weinberg比例的隨機交配系統 ……………………………….. 12 3.5 雌雄二次群體之基因型頻率不在Hardy-Weinberg比例且基因型頻率不同但對偶基因頻率相同下其子代群體基因型頻率會達到Hardy-Weinberg比例的隨機交配系統 ………………………. 13 3.6 雌雄二次群體之基因型頻率不在Hardy-Weinberg比例且基因型及對偶基因頻率皆不同的隨機交配系統 之子代群體基因型頻率不會達到Hardy-Weinberg比例………………………………. 14 3.7 隨機交配族群基因型頻率會達到Hardy-Weinberg比例的交配系統之結論與彙整………………………………………………………. 14 第四章 族群達到Hardy-Weinberg比例的隨機交配系統之性質 17 4.1 隨機交配系統 及其子代群體配子結合之相關係數…………... 17 4.1.1 隨機交配系統 之相關係數………………………………... 17 4.1.2 隨機交配系統 之子代群體配子結合的相關係數……….. 18 4.2 ITO方法及其應用……………………………………………………. 19 4.3 隨機交配系統 之親代和子代基因型聯合頻率矩陣及其相關係數. 21 4.3.1 隨機交配系統 之母子基因型聯合頻率矩陣及其相關係數... 20 4.3.2 隨機交配系統 之父子基因型聯合頻率矩陣及其相關係數... 23 4.3.3 隨機交配系統 之親子基因型聯合頻率矩陣及其相關係數... 24 4.4 隨機交配系統 之二同胞基因型聯合頻率矩陣及其相關係數.. 25 4.5 隨機交配族群基因型頻率達到Hardy-Weinberg比例的交配系統之性質比較……………………………………………………………. 27 第五章 母父子基因型的傳遞機率矩陣及其應用……………….. 28 5.1 母父子基因型的傳遞機率矩陣………………………………………. 28 5.2 子代群體基因型頻率之矩陣代數算法………………………………. 31 5.2.1 不區分異質結合基因型的子代群體基因型頻率……………... 32 5.2.2 區分異質結合基因型的子代群體基因型頻率………………... 33 5.3 親代和子代基因型聯合頻率之矩陣代數算法……………………… 34 5.3.1 母子基因型聯合頻率矩陣之矩陣代數算法…………………... 34 5.3.2 父子基因型聯合頻率之矩陣代數算法………………………… 35 5.4 二同胞基因型聯合頻率之矩陣代數算法…………………………… 36 第六章 族群達到Hardy-Weinberg比例之非隨機交配系統…... 41 6.1 雌雄二次群體之基因型頻率在Hardy-Weinberg比例且基因型及對偶基因頻率皆相同下其子代群體基因型頻率會達到Hardy-Weinberg比例的非隨機交配系統 …………………………….. 41 6.2 雌雄二次群體之基因型頻率不在Hardy-Weinberg比例且基因型與對偶基因頻率皆不同但其子代群體基因型頻率達到Hardy-Weinberg比例的非隨機交配系統 …………………………….. 44 6.3 非隨機交配系統 的另一種表示法……………………………… 46 6.4 雌雄二次群體之基因型頻率在Hardy-Weinberg比例但基因型及對偶基因頻率皆不同下其子代群體基因型頻率會達到Hardy-Weinberg比例的非隨機交配系統 …………………………….. 50 6.5 雌雄二次群體之基因型頻率不在Hardy-Weinberg比例但基因型及對偶基因頻率皆相同下其子代群體基因型頻率會達到Hardy-Weinberg比例的非隨機交配系統 …………………………….. 52 6.6 雌雄二次群體之基因型頻率不在Hardy-Weinberg比例且基因型頻率不同但對偶基因頻率相同下其子代群體基因型頻率會達到Hardy-Weinberg比例的非隨機交配系統 …………………… 53 6.7 非隨機交配族群基因型頻率會達到Hardy-Weinberg比例的交配系統之彙整……………………………………………………………. 54 第七章 族群達到Hardy-Weinberg比例的非隨機交配系統之性質……………………………………………………….. 56 7.1 雌雄交配基因型聯合頻率矩陣 之相關係數………………….. 56 7.2 之子代群體配子結合的相關係數……………………………… 58 7.3 之親代和子代基因型聯合頻率矩陣及其相關係數………….. 60 7.3.1 之母子基因型聯合頻率矩陣及其相關係數…………….. 61 7.3.2 之父子基因型聯合頻率矩陣及其相關係數…………….. 64 7.4 之二同胞基因型聯合頻率矩陣及其相關係數……………… 64 7.5 非隨機交配族群之子代群體基因型頻率達到Hardy-Weinberg比例的交配系統之性質比較…………………………………………… 69 第八章 族群達到Wright比例的交配系統及其性質……………. 71 8.1 Wright平衡定律……………………………………………………… 71 8.2 族群基因型頻率達到Wright比例的交配系統之最一般化型式 … 72 8.3 族群基因型頻率會達到Wright比例之交配系統的整體架構中其餘各交配系統之存在性………………………………………………. 77 8.3.1 雌雄二次群體之基因型頻率在Hardy-Weinberg比例且基因型及對偶基因頻率皆相同其子代群體基因型頻率會達到Wright比例的交配系統 …………………………………. 77 8.3.2 雌雄二次群體之基因型頻率不在Hardy-Weinberg比例但基因型及對偶基因頻率皆相同其子代群體基因型頻率會達到Wright比例的交配系統 …………………………………. 78 8.3.3 族群基因型頻率達到Wright比例的交配系統之彙整……….. 80 8.4 族群基因型頻率會達到Wright比例的交配系統之性質………… 82 8.4.1 雌雄交配基因型聯合頻率矩陣 之相關係數……………. 82 8.4.2 之親代和子代基因型聯合頻率矩陣及其相關係數……. 84 8.4.3.1 之母子基因型聯合頻率矩陣及其相關係數……… 84 8.4.3.2 之父子基因型聯合頻率矩陣及其相關係數………. 87 8.4.3 之二同胞基因型聯合頻率矩陣及其相關係數…………. 87 8.4.4 族群基因型頻率會達到Wright比例的交配系統之性質的結論與彙整………………………………………………………… 89 第九章 一般化平衡族群的交配系統及其性質………………….. 91 9.1 一般化平衡定律………………………………………………………. 91 9.2 非隨交配族群基因型頻率達到一般化比例的交配系統之最一般化型式 ……………………………………………………………… 93 9.3 雌雄二次群體之基因型頻率在Hardy-Weinberg比例但基因型與對偶基因頻率皆不同的一般化平衡族群之交配系統 ………… 98 9.4 一般化平衡族群的交配系統之性質………………………………… 100 9.4.1 雌雄交配基因型聯合頻率矩陣 之相關係數……………… 100 9.4.2 之子代群體配子結合之相關係數………………………… 102 9.4.3 之親代和子代基因型聯合頻率矩陣及其相關係數……… 104 9.4.3.1 之母子基因型聯合頻率矩陣及其相關係數……….. 104 9.4.3.2 之父子基因型聯合頻率矩陣及其相關係數………... 106 9.4.4 之二同胞基因型聯合頻率矩陣及其相關係數…………… 106 9.4.5 一般化平衡族群之性質彙整…………………………………… 109 第十章 結論與未來研究方向…………………………………….. 111 10.1 結論……………………………………………………………………. 111 10.2 未來研究方向…………………………………………………………. 115 參考文獻…………………………………………………………….. 117 / In population genetics it is known that there are many factors that may affect the genotypic and gene distributions of a population. The type of mating of a population is one of them. For examples, basically Hardy-Weinberg equilibrium law refers to a population undergoing random mating, and Wright's equilibrium law in inbreeding refers to a special type of nonrandom mating. This study performs a comprehensive investigation of all possible matings that can attain Hardy-Weinberg proportions or Wright proportions that had been or not had been discussed previously. The framework of mating systems attaining the Hardy-Weinberg proportions or Wright proportions will be established on the basis of pooling together factors such as the mating behavior, gene frequencies, genotypic frequencies and the Hardy-Weinberg proportions of the male and female subpopulations. The type and property of each mating system corresponding to each point of the established mating system framework are examined.

Orientador: Mário Luiz Teixeira de Moraes / Banca: Magali Ribeiro da Silva / Banca: Cantídio Fernando Gouvêa / Resumo : Handroanthus heptaphyllus (Vell.) Mattos, sinonímia Tabebuia heptaphylla ( Vell.) Toledo, popularmente conhecida por ipê-roxo, é uma espécie pertencente a família Bignoneaceae, muito apreciada pela sua beleza, madeira de excelente qualidade, além de algumas espécies dessa família possuírem substâncias as quais são usadas como produtos medicinais. A espécie é polinizada por abelhas, pássaros e outros visitantes que podem se alimentar das flores e dos frutos. Atualmente é utilizada em programas de reflorestamento de áreas degradadas, paisagismo e restauração. Ocorre em grande parte do Brasil, desde o Estado da Bahia até o Rio Grande do Sul, Minas Gerais, Mato Grosso do Sul, Santa Catarina e São Paulo, compreendendo as latitudes de 13ºS (BA) a 30ºS (RS). O trabalho teve como objetivos estudar a variabilidade genética entre e dentro das subpopulações de H. heptaphyllus, por meio de marcadores microssatélites e conhecer sobre o seu sistema reprodutivo. Para tanto, foram colhidas sementes de 30 árvores, na região de Botucatu, S.P., sendo grande parte na Fazenda Experimental Lageado pertencente a UNESP - Campus de Botucatu. As sementes foram semeadas no viveiro da UNESP e as folhas das mudas produzidas foram coletadas para a extração de DNA e posteriormente analisadas em géis de poliacrilamida. No total, foram estudados oito locos microssatélites polimórficos, que apresentaram desde seis alelos por loco (loco TAU22) a 14 alelos (locos TAU12, TAU30 e TAU31). A média de heterozigosidade esperada ( e H ˆ ) para as seis subpopulações foi de 0,732, sendo que a heterozigosidade observada ( o H ˆ ) foi de 0,618. Os índices médios de fixação variaram de -0,082 (subpopulação 4) a 0,255 (subpopulação 3), com média de 0,152. Os resultados das subpopulações estudadas mostraram os índices de fixação em níveis aceitáveis, com média de 15,2%, no entanto... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Handroanthus heptaphyllus (Vell.) Mattos, sinonímia Tabebuia heptaphylla (Velloso) Toledo, known as ipê-roxo, belongs to the Family Bignoniaceae. It is a very important Brazilian forest tree species because of its beautiful flowers, excellent wood quality, and medicinal properties. Its flowers are usually visited by animals, like bees, birds, bats, etc, for feeding and for pollination purposes. The species has also been used in programs of reforestation of degraded areas, landscaping, and restoration. The ipê-roxo is widespread throughout Brazil, from Bahia State to Rio Grande do Sul, Minas Gerais, Mato Grosso do Sul, Santa Catarina, and São Paulo States, from 13ºS (BA) to 30ºS (RS) latitudes. The research has as objectives to study the genetic diversity within and between subpopulations of H. heptaphyllus by microsatellite molecular markers and to understand its mating system. We collected seeds of 30 trees, through the Botucatu region, Brazil, mostly from the Lageado Experimental Station, São Paulo State University (UNESP) - Botucatu. The seeds were sown in a nursery and the leaves were collected, to extract the DNA, and analyzed through polyacrilamide gels. In a total of eight polymorphic microsatellite loci were analyzed that varied from six alleles (TAU22 locus) to 14 alleles (TAU12, TAU30, and TAU31 loci). The expected heterozygosity mean ( e H ˆ ) for the six subpopulations was 0.7318, the observed heterozygosity mean ( o H ˆ ) was 0.6183, and the average of fixation index (f) between pairs of the six population varied from -0,082 (subpopulation 4) to 0.255 (subpopulation 3), with an average of 0.152. The results of the studied subpopulations have shown acceptable levels of fixation index, presenting an average of 15.2%, therefore, the subpopulation 4 has shown a higher amount of heterozygous than expected. The total genetic diversity ( IT fˆ ) for the six subpopulations... (Complete abstract click electronic access below) / Mestre

ABSTRACT A major focus in biology is understanding the diversification of life and the processes that cause it. Much of this diversity is in the form of phenotypic variation among populations and species. In this thesis, I investigate two separate aspects of such phenotypic divergence. The first is the divergence of male mate preferences and their potential contribution to precopulatory sexual isolation and speciation. The second is the divergence of postcopulatory phenotypic divergence in the form of seminal fluid protein expression. With respect to the first aspect, in two separate experiments I investigated the contribution of male mate preferences to sexual isolation between two closely related fruit fly species experiencing differential costs to hybridization, Drosophila recens and Drosophila subquinaria. Male mate preferences are of particular interest because of their potential contribution to sexual isolation, a form of reproductive isolation which can contribute to speciation in sexually reproducing species. In the first experiment, I test for the presence of male mate preferences in each of the two species and whether the relative strength of the preference is concordant with the cost of hybridization. I found that that D. subquinaria males indiscriminately courted both their own (i.e. homospecific) females and heterospecific D. recens females. While D. recens from allopatry showed a similar pattern, those from sympatry courted their own females more than heterospecific females, indicating a pattern of reproductive character displacement. In the second experiment I test the role of learning in the context of these male mate preference in D. recens, and whether learning also showed a pattern of reproductive characteristic. I did not find evidence of learning in that D. recens males did not reduce their courting intensity towards heterospecific females after experiencing rejection by similar females. Consequently, I did not find an indication of reproductive character displacement. Finally, with respect to postcopulatory phenotypic divergence, I studied differences in seminal fluid protein expression between experimental populations of D. melanogaster experiencing one of three mating environments allowing for differing opportunities of mate competition and the environment in which it took place. These three mating environments include one in which mate competition was absent (MCabsent,), one in which mate competition occurred in a small, structurally simple environment (MCsimple), and one in which mate competition occurred in a larger, somewhat more complex environment (MCcomplex,). Male seminal fluids are of particular interest due to their ability to mediate postcopulatory competition between males and, therefore, can be used to manipulate females to a male’s own fitness benefit, potentially at her expense (i.e. sexual conflict). I investigated divergence in one particular seminal fluid protein implicated in sexual conflict, sex peptide (Acp70A). Whereas, gene expression levels among males from the three-mating treatment did not differ on average, relative stored quantities did, with MCcomplex males carrying significantly less sex peptide than either of MCabsent or MCsimple males (which did not differ from one another). This result suggests that mate competition and the environment in which it occurs play a significant role in the divergence of sex peptide phenotypes. ABSTRAIT Un objectif majeur de la biologie est de comprendre la diversification de la vie et les processus qui la provoquent. Une grande partie de cette diversité se présente sous la forme de variations phénotypiques entre les populations et les espèces. Dans cette thèse, j'étudie deux aspects distincts d'une telle divergence phénotypique. Le premier est la divergence des préférences des mâles et leurs contributions potentielles à l'isolement sexuel pré-copulatoire et à la spéciation. Le second est la différence de la divergence phénotypique post-copulatoire sous la forme de l'expression des protéines du liquide séminal. En ce qui concerne le premier aspect, dans deux expériences distinctes, j'ai étudié la contribution des préférences de compagnon mâle à l'isolement sexuel entre deux espèces de mouches des fruits étroitement liées subissant des coûts différentiels d'hybridation, Drosophila recens et Drosophila subquinaria. Les préférences des mâles sont particulièrement intéressantes en raison de leurs contributions potentielles à l'isolement sexuel, une forme d'isolement reproductif qui peut contribuer à la spéciation des espèces se reproduisant sexuellement. Dans la première expérience, je teste la présence de préférences de compagnon mâle dans chacune des deux espèces et si la force relative de la préférence est concordante avec le coût de l'hybridation. J'ai constaté que les mâles de D. subquinaria courtisaient sans discernement à la fois leurs propres femelles (c'est-à-dire homospécifiques) et les femelles hétérospécifiques de D. recens. Alors que D. recens de l'allopatrie a montré un modèle similaire, ceux de la sympatrie courtisaient leurs propres femelles plus que les femelles hétérospécifiques, indiquant un modèle de déplacement du caractère reproducteur. Dans la deuxième expérience, je teste le rôle de l'apprentissage dans le contexte de ces préférences de compagnon masculin dans D. recens, et si l'apprentissage a également montré un modèle de caractéristique de reproduction. Je n'ai pas trouvé de preuve d'apprentissage dans la mesure où les mâles D. recens ne réduisaient pas leur intensité de fréquentation envers les femelles hétérospécifiques après avoir été rejetés par des femelles similaires. Par conséquent, je n'ai pas trouvé d'indication de déplacement du caractère reproducteur. Enfin, en ce qui concerne la divergence phénotypique post-copulatoire, j'ai étudié les différences dans l'expression des protéines du liquide séminal entre les populations expérimentales de D. melanogaster connaissant l'un des trois environnements d'accouplement, permettant différentes possibilités de compétition de compagnon et l'environnement dans lequel elle a eu lieu. Ces trois environnements d'accouplement incluent un environnement dans lequel la compétition entre partenaires était absente (MCabsent,), un dans lequel la compétition entre partenaires se produisait dans un petit environnement structurellement simple (MCsimple) et un dans lequel la compétition entre partenaires se produisait dans un environnement plus grand et un peu plus complexe (MCcomplexe,). Les fluides séminaux mâles sont particulièrement intéressants en raison de leur capacité à négocier la compétition post-copulatoire entre les mâles et, par conséquent, peuvent être utilisés pour manipuler les femelles dans l'intérêt de la forme physique d'un mâle, potentiellement à ses dépens (c'est-à-dire conflit sexuel). J'ai étudié la divergence dans une protéine du liquide séminal particulière impliquée dans un conflit sexuel, le peptide sexuel (Acp70A). Alors que les niveaux d'expression génique chez les mâles du traitement à trois accouplements ne différaient pas en moyenne, les quantités relatives stockées le faisaient, les mâles MCcomplexe portant significativement moins de peptide sexuel que les mâles MCabsent ou MCsimple (qui ne différaient pas les uns des autres). Ce résultat suggère que la compétition de partenaire et l'environnement dans lequel elle se produit jouent un rôle important dans la divergence des phénotypes des peptides sexuels.

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Natural selection mediated by pollinators has influenced the evolution of floral diversity of the flowering plants (angiosperms). The scope of this thesis was to study: 1) phenotypic selection, 2) mating systems, and 3) floral shifts involved in plant speciation. Model plant species were Platanthera bifolia and P. chlorantha (Orchidaceae). These orchids are moth-pollinated, strictly co-sexual (bisexual flowers), and produce a spike that displays 10-20 white flowers. I explored the influence of characters on plant fitness by using multiple linear regressions. Pollen removal (male fitness) and fruit set (female fitness) increased with more flowers per plant in three P. bifolia populations. There was selection towards longer spurs in a dry year when average spur length was shorter than in normal-wet years. Female function was sensitive to drought, which enabled an application of the male function hypothesis of floral evolution (Bateman's principle). The results show that selection may vary between populations, years, and sex-functions. I examined inbreeding by estimating levels of geitonogamy (self-pollination between flowers of an individual) with an emasculation method in two P. bifolia populations. Geitonogamy did not vary with inflorescence size. Levels of geitonogamy was 20-40% in the smaller, but non-significant in the larger population. This may relate to lower number of possible mates and pollinator activity in the smaller population. Platanthera bifolia exhibits the ancestral character state of tongue-attachment of pollinia on the pollinator. Its close relative P. chlorantha attaches its pollinia onto the pollinator's eyes. To explore the mechanism of a floral shift, pollination efficiency and speed was compared between the two species. The results showed no differences in pollination efficiency, but P. chlorantha had faster pollen export and import. Efficiency of pollination in terms of speed may cause floral shifts, and thus speciation.