京都大学 / 0048 / 新制・課程博士 / 博士(農学) / 甲第20636号 / 農博第2243号 / 新制||農||1053(附属図書館) / 学位論文||H29||N5080(農学部図書室) / 京都大学大学院農学研究科地域環境科学専攻 / (主査)教授 北山 兼弘, 教授 田中 千尋, 教授 松浦 健二 / 学位規則第4条第1項該当 / Doctor of Agricultural Science / Kyoto University / DGAM

Considering the high reproductive investment of the social male and the cost to the female of losing this benefit by soliciting copulations outside the social pair bond, it is expected that most raptor populations would exhibit low to no occurrence of extra-pair paternity (EPP). This holds true for the majority of raptor species studied to date with only one exception of an urban Cooper's hawk (Accipiter cooperii) study which reported an unexpectedly high extra-pair young frequency of 19.29%. In our study we examined the frequency of EPP within a red-shouldered hawk (Buteo lineatus) population residing in the suburban/urban matrix of southwest Ohio. During the breeding seasons of 2018 and 2019, 181 breeding age and nestling individuals were color-banded and sampled for genetic analysis using nine microsatellite loci. After genotyping a total of 40 broods (with at least two nestlings per brood) and both presumptive parents of each brood, no clear evidence of EPP was detected. However, at one nest site, the entire brood of four chicks was not sired by the adult male observed during the courtship period, nor another adult male observed tending the chicks later in the season. We suspect that this particular nest represented two instances of rapid mate replacement rather than extra-pair fertilization by a third unsampled male, because none of the chicks were sired by either of the two adult males observed at the nest. We also reviewed potential factors contributing to our finding of overall genetic monogamy in our study population in comparison to other raptor taxa EPP studies. Our results suggested that factors other than habitat composition alone play an important role in determining the type of breeding strategy exhibited by different raptor populations.

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No description available.

<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>

Buzz-pollination or pollination by vibration occurs in several families of angiosperms including some important commercial crops such as potatoes and tomatoes. Buzz-pollinated flowers release pollen via small pores or slits on the anther’s tip that require the use of vibrations by specialized pollinators, usually bees, to remove the pollen. Some buzz-pollinated species have elaborate floral morphologies including dimorphic anthers within the same flower (heteranthery), and mirror-image flowers (enantiostyly) where the style is reciprocally deflected to either the left or right side of the floral axis. The complex floral morphology and buzz-pollination syndrome seen in these species require a close physical interaction between the sexual organs of the flowers and the bodies of insect visitors. Despite the broad taxonomic distribution of buzz-pollination in angiosperms (more than 60 families are buzz-pollinated) relatively few studies have described the pollination ecology of these species under natural conditions. The main goal of the present work was to characterize the pollination biology, mating patterns and antagonistic interactions (e.g. pollen theft) in natural populations of a buzz-pollinated species. For this purpose, I studied Solanum rostratum (Solanaceae), a buzz-pollinated, self-compatible, annual weed with complex floral morphology (both enantiostylous and heterantherous flowers). This species usually grows in disturbed areas in its native range (Mexico) and has become invasive around the world. My research was divided into three components. First, I characterized the pollination and reproductive biology of natural populations in Mexico. I performed floral manipulations in six natural populations of S. rostratum to estimate fruit and seed set. In three of these populations, I carried out 115 hours of pollinator observations and quantified the incidence of pollinators versus pollen thieves. I also measured the efficiency of a subset of floral visitors in triggering fruit set after single visits. Second, I investigated whether morphological correspondence between the size of the pollinator’s body and floral morphology influences pollen transfer. In experimental arrays, I exposed flowers of S. rostratum that varied in the distance between their sexual organs, to bumblebees (Bombus terrestris) of different sizes, and recorded pollen deposition and fruit and seed production. Finally, I determined the mating system (i.e. the proportion of self- and cross-fertilized offspring) of natural populations in Mexico and of introduced populations in the United States of America, using newly developed microsatellite markers. My results show that S. rostratum is visited by a wide range of bees of different sizes (0.9–9.8 mm in thorax diameter), but that only a small subset of these visitors act as pollinators. Most visitors act as pollen thieves, consuming pollen while effecting little or no pollination. I also found that correspondence between a pollinator’s size and the separation of the S. rostratum sexual organs determines pollen deposition and fruit production; pollen deposition decreased when bees were small relative to the distance between the sexual organs visited the flowers. My genetic analyses show that natural populations of S. rostratum maintain a relatively high outcrossing rate (tm = 0.75 ± 0.03) across the native and introduced range. Furthermore, genetic diversity is reduced in invasive populations, but this is not accompanied by changes in mating system. My work shows that the morphological fit between the pollinator and the flowers is important in determining the dynamics of pollen transfer and fruit production in this buzz-pollinated plant. Distinguishing between pollinators and pollen thieves in buzz-pollinated plants is essential for understanding the evolution of buzz-pollination, as pollen theft could be a major selective force for these species.

Understanding how floral traits covary with one another and with mating patterns is an important step in understanding how and why mating systems evolve. I examined the evolution of floral and mating system variation in Camissoniopsis cheiranthifolia (Onagraceae), a species that exhibits divergence in key floral traits expected to be associated with variation in the relative importance of outcrossing vs. self-fertilization. I combined geographic surveys of floral variation with genetic estimates of the proportion of seeds outcrossed (t) and confirmed that t covaried with corolla width and herkogamy in a predictable way both within and among populations. I then performed geographic surveys, manipulative experiments and genetic analyses to evaluate the potential role that; inbreeding depression (ID), interactions between flowers, pollinators and florivores, and reproductive assurance (RA) may have played in shaping and/or maintaining the geographic pattern of mating system variation in this species. The main selective factor maintaining outcrossing in large flowered (LF) populations appears to be ID, which was much stronger in LF compared to small flowered (SF) populations. These results are also consistent with purging of ID in SF populations. Increased selfing appeared to alleviate pollen limitation (PL) because it was associated with higher and less variable fruit set and reduced florivory by a microlepidopteran. However, evidence that florivores preferentially attacked larger flowers was equivocal. LF experienced stronger PL than SF populations suggesting that one condition for the evolution of selfing via RA is met in outcrossing populations. Floral emasculation experiments revealed that the timing of selfing also covaried with flower size among and within populations. SF self-pollinate before flowers open but LF do not, suggesting that selfing evolved in response to chronic outcross PL. Negative side effects of emasculation were detected which prevented a clear interpretation of the RA value of selfing. Given that much of what is known about RA comes from emasculation experiments, my results suggest that the assumptions of this approach, which are rarely verified, require more serious consideration. Taken together my results suggest that C. cheiranthifolia has evolved multiple stable mixed mating systems perhaps in response to selection for RA. / Thesis (Ph.D, Biology) -- Queen's University, 2012-12-30 14:13:46.366

Gaining a good understanding of marine turtle mating systems is fundamental for their effective conservation, yet there are distinct gaps in our knowledge of their breeding ecology and life history, owing largely to the difficulty in observing these highly mobile animals at sea. Whilst multiple mating by females, or polyandry, has been documented in all marine turtle species, the fitness consequences of this behaviour have not been fully investigated. Furthermore, male mating patterns, operational sex ratios and the number of males contributing to breeding populations are poorly understood, impeding accurate assessments of population viability. In this thesis, I use molecular-based parentage analysis to study, in detail, the genetic mating system of two green turtle (Chelonia mydas) populations. In the focal population in northern Cyprus, I show that, despite exhibiting a strongly female-biased hatchling sex ratio and contrary to our expectations, there are at least 1.3 breeding males to every nesting female. I go on to assess the breeding frequency of male turtles in the population and determine that males do not breed annually at this site, demonstrating that the observed relatively equal sex ratio of breeders is not the result of a few males mating every year, but that the number of breeding males in the population is greater than expected. I show that 24% of nesting females in the population produce clutches with multiple paternity, but do not detect any fitness benefits to polyandrous females, and discuss the potential role of sexual conflict in influencing female mating decisions. Finally, I reveal a high frequency of multiple paternity in green turtle clutches on Ascension Island, one of the largest green turtle rookeries in the world, and discuss possible causes of variation in the level of polyandry among marine turtle populations. The results presented here shed new light on aspects of marine turtle mating systems that are challenging to study, and illustrate the value of molecular data, not only in describing mating patterns, but in elucidating aspects of life history and behaviour that would otherwise be very difficult to ascertain.

O bioma Mata Atlântica tem sofrido com a fragmentação florestal e como forma de reestabelecer ambientes florestais são realizados plantios de restauração. Porém, por muito tempo houve preocupação somente com a composição florística das áreas e a diversidade genética foi negligenciada. Além disso, muitas áreas são implantadas a partir de sementes coletadas em áreas florestais geralmente pouco conservadas, pequenas e isoladas, o que pode comprometer a qualidade genética das mudas, produzindo indivíduos menos adaptados em decorrência da depressão endogâmica. Assim este trabalho teve como objetivo principal analisar o aspecto genético em áreas de restauração na região do Pontal do Paranapanema e área natural de referência, o Parque Estadual Morro do Diabo (PEMD), utilizando o jatobá (Hymenaea courbaril L.) como espécie modelo. No capítulo 1 com o objetivo de verificar a diversidade genética de H. courbaril em áreas de restauração florestal, foram selecionadas duas áreas de plantio com espécies nativas. Nestas áreas e no PEMD foram coletadas amostras foliares de indivíduos adultos que foram genotipadas para oito locos microssatélites. No PEMD ainda foram coletados frutos em 12 matrizes para caracterização do sistema reprodutivo. As três áreas estudadas apresentaram diversidade genética e níveis de endogamia similares. Nas três áreas de estudo foi identificada baixa estruturação genética espacial. Houve predomínio de fecundação cruzada para a produção de frutos na área natural, porém a taxa de cruzamentos entre indivíduos aparentados foi até dez vezes maior que a observada em outras populações da espécie. No capítulo 2 com o objetivo de verificar se há depressão endogâmica em progênies provenientes do PEMD foram selecionadas 320 sementes de 12 matrizes. Estas e seus frutos foram medidos. As plântulas a que deram origem também foram mensuradas, mensalmente, durante 15 meses. Todos os indivíduos foram genotipadas para oito locos microssatélites. A coancestria, foi estimada e os indivíduos separados em: não aparentados (tu), aparentados (tr) e autofecundação (s). Foi verificada diferença entre as métricas das plantas de acordo com o nível de coancestria entre indivíduos. Também foram estimados os valores de depressão endogâmica (ID). A quantidade de indivíduos irmãos de autofecundação foi muito pequena, sendo a maioria proveniente de cruzamento entre indivíduos não aparentados. A depressão endogâmica por autofecundação foi mais evidente no peso e tamanho dos frutos, e amena ou inexistente para os demais caracteres. Isto provavelmente por estas sementes terem sido coletadas em um fragmento grande e bem conservado e que ainda não sofre as consequências da depressão endogâmica. Assim, nosso trabalho mostrou que áreas de restauração florestal que seguiram as recomendações genéticas de implantação, apresentam diversidade genética suficiente para H. courbaril, podendo estas áreas serem fonte de coleta de sementes no futuro. E que os indivíduos provenientes de sementes do PEMD não apresentaram efeito de depressão endogâmica até 15 meses de desenvolvimento em viveiro. / The Brazilian Atlantic Forest was severely deforested and restoration initiatives are necessary to reestablish environments. However, for a long time there is only concern over floristic composition and the genetic diversity has been neglected. In addition, several restoration areas are planted from seeds collected in forest areas that are generally poorly preserved, small and isolated, which may compromise the genetic quality of the seedlings, producing less adapted individuals due to inbreeding depression. The aim of this work was to analyze the genetic aspects of Hymenaea courbaril L. in restoration areas in Pontal do Paranapanema region, and a natural reference forest, the Morro do Diabo State Park (PEMD), where seeds were also collected. In Chapter 1, to verify the genetic diversity of H. courbaril in areas of forest restoration, using eight microsatellites, two restoration areas were selected. In these areas and in the PEMD, leaf samples from adult individuals were collected. In the PEMD, fruits were collected in 12 seed trees for mating system characterization. The three areas presented similar genetic diversity and levels of inbreeding. Low spatial genetic structure was identified in the three studied areas. In the natural forest, fruits were mainly produced through outcrossings, but the rate of mating among relatives was up to ten times higher than the observed in other H. courbaril populations. In Chapter 2, to verify the inbreeding depression in the PEMD were selected 320 seeds from eight seed trees. The seeeds and their fruits were measured. The seedlings were also measured monthly, during 15 months. All seedlings were genotyped with eight microsatellite loci. From the pairwise coancestry the seedlings were separated into three categories: outcrossing among unrelated individuals (tu), outcrossing among related individuals (tr), and selfing (s). We verified differences among groups in the metrics of seedlings according to the level of coancestry among individuals. The values of inbreeding depression (ID) were also estimated. The number of selfed seedlings were very small, and the majority were from outcrossing among unrelated individuals. Inbreeding depression by selfing was more evident in weight and size fruit, and was insignificant or non-existent for other characters. This is probably because these seeds were collected in a large and preserved forest fragment, that does not suffer the consequences of inbreeding depression yet. Thus, our work showed that forest restoration areas that followed the genetic recommendations present enough genetic diversity for H. courbaril, and these areas may be a source of seeds for collection in the future. Besides that, seedlings from seed trees in PEMD did not present inbreeding depression effect up to 15 months of nursery development.

Balfourodendron riedelianum (Engl.) Engl. e uma espécie arbórea tropical que ocorre na Mata Atlântica e está em perigo de extinção devido a fragmentação do bioma e a exploração de sua madeira. Atualmente três populações da espécie estão sendo conservadas em um teste de procedências e progênies implantado na Estação Experimental de Luiz Antonio, estado de São Paulo, Brasil. O teste e composto por procedências de Alvorada do Sul, estado do Paraná, Gália e Bauru, ambas do estado de São Paulo. Com o objetivo de verificar o potencial do teste como fonte de sementes para a recomposição florestal, esse estudo avaliou a biometria de frutos, geminação de sementes, mortalidade e sobrevivência de plântulas da espécie. Foram desenvolvidos, marcadores microssatélites para a análise da diversidade genética, endogamia, sistema de reprodução, fluxo e dispersão de pólen e depressão por endogamia (DE). A variação observada entre as matrizes para a biometria de frutos, assim como para germinação, mortalidade e sobrevivência sugerem que estas sejam decorrentes da variabilidade genética, não foi detectada correlação entre a biometria e germinação. Os microssatélites apresentaram alto nível de polimorfismo e ausência de desvios de segregação Mendeliana, ligação genética e desequilíbrio de ligação. A procedência Gália apresentou a maior riqueza alélica (R = 10,3), heterozigosidade esperada (He = 0,60) e índice de fixação (F = 0,11) e a procedência Alvorada do Sul apresentou a maior heterozigosidade observada (Ho = 0,58) e o menor índice de fixação (F = -0,01). As plântulas apresentaram a menor riqueza alélica (R = 9,4) e heterozigosidade observada (Ho = 0,48) e o maior índice de fixação (F = 0,16). A taxa de cruzamento (tm) foi alta (> 0,93), mas foi observado para as plântulas uma variação individual na taxa de cruzamento (tm = 0,68 a 0,99), cruzamento entre parentes (tm - ts = 0 a 0,18) e na correlação de paternidade (rp = 0,041 a 0,182), o que indica que a espécie se reproduz predominantemente por cruzamentos, e autocompatível e que a reprodução não foi aleatória. A distância média de dispersão do pólen (71 m) maior que a mediana (21 m) sugere um padrão de isolamento por distância. Aos 12 meses as plântulas oriundas de autofecundação apresentaram os menores valores de C e Ho e o maior F (2,98 mm; 0,25 e 0,61) do que as de cruzamento entre parentes (3,10 mm, 0,34 e 0,29, respectivamente) e não parentes (3,30 mm, 0,51 e 0,07, respectivamente). A autofecundação resultou em maior DE para circunferência a altura do colo (9,6%) e o cruzamento entre parentes para altura (2,6%). Para fins de conservação, sementes de no mínimo 53 arvores devem ser coletadas para alcançar um Ne(ref) de 150 indivíduos, da mesma forma, devem ser mantidos também pelo menos 53 indivíduos com a mesma fenologia de florescimento a cada ciclo de desbaste. A endogamia decorrente de cruzamentos entre parentes pode ser minimizada se apenas uma planta por família for selecionada dentro das parcelas e pode ser eliminada se apenas uma planta por família for selecionada no teste, sendo possível obter ganhos com a seleção em ambos os casos. / Balfourodendron riedelianum (Engl.) Engl. is a tropical tree species of the Atlantic Forest that is endangered due to exploitation of its wood and biome fragmentation. Currently, three populations of the species are preserved in a provenance and progeny test established in the Luiz Antônio Experimental Station, São Paulo State, Brazil. The test consists of provenances from Alvorada do Sul, Parana State, and Galia and Bauru, both from São Paulo State. In order to verify the potential of the test as a seed source for forest restoration, this study evaluates the species\' fruit biometry, seed germination, mortality and seedling survival. Microsatellite markers were developed to analyze genetic diversity, inbreeding, mating system, pollen flow and dispersal, and inbreeding depression (ID). The variation observed between seed trees for fruit biometry, as well as for germination, mortality and survival, suggests a correlation with genetic variability. No correlation was detected between biometry and germination. Microsatellites presented a high level of polymorphism and an absence of deviation from Mendelian segregation, genetic linkage, and linkage disequilibrium. The Galia population had the highest allelic richness (R = 10.3), expected heterozygosity (He = 0.60), and fixation index (F = 0.11), and Alvorada do Sul had the highest observed heterozygosity (Ho = 0.58) and the lowest fixation index (F = -0.01). Seedlings showed the lowest allelic richness (R = 9.4) and observed heterozygosity (Ho = 0.48) and the highest fixation index (F = 0.16). The outcrossing rate (tm) was high (> 0.93). However, there was individual variation in seedlings for the outcrossing rate (tm = 0.68 to 0.99), mating between relatives (tm - ts = 0 to 0.18), and paternity correlation (rp = 0.041 to 0.182), indicating that the species has a predominantly outcrossed mating system, is selfcompatible, and that reproduction is not random. The mean pollen dispersal distance (71 m) was greater than the median (21 m), suggesting a pattern of isolation by distance. At 12 months, seedlings resulting from selfing had the lowest values of C, Ho, and higher F (2.98 mm, 0.25, and 0.61, respectively) than those from mating between relatives (3.10 mm, 0.34, and 0.29) and unrelated individuals (3.30 mm, 0.51, and 0.07). Selfing resulted in higher ID for root-collar circumference (9.6%) and mating between relatives showed a higher ID for height (2.6%). For conservation purposes, seeds of at least 53 trees must be collected to reach Ne(ref) of 150 individuals and at least 53 individuals with the same flowering phenology must be maintained at each thinning cycle. Inbreeding resulting from crosses between relatives can be minimized if only one plant per family is selected within the plots and can be eliminated if only one plant per family is selected in the test, thus enabling gains with selection in both cases.