京都大学 / 新制・課程博士 / 博士(理学) / 甲第24181号 / 理博第4872号 / 新制||理||1697(附属図書館) / 京都大学大学院理学研究科生物科学専攻 / (主査)教授 中務 真人, 教授 森 哲, 准教授 森本 直記 / 学位規則第4条第1項該当 / Doctor of Science / Kyoto University / DFAM

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Changing environmental conditions often impose stressful growing conditions in plant communities. Until now, morphological plasticity, i.e. polymorphic growth physiognomies of plants, has not been sufficiently studied as a pivotal strategy for the whole ecosystem adaptation to environmental stress. We consider mangrove ecosystems as suitable models to provide insights on this subject. In the thesis, I investigate the ecological significance of tree morphological plasticity in the structural development and the dynamics of mangrove forests. I conducted field experiments in two regions located on both sides of the Amazon River mouths i.e. in French Guiana and North Brazil. Forest inventories were carried out in contrasting mangrove stands in both regions. The thesis combines empirical analysis of field data, terrestrial laser scanning (TLS), and mechanistic, individual-based computer simulations. We published results that proved the TLS-based analysis of individual tree structure useful for a better knowledge on biomass allocation between trunk and branches in tall and large Avicennia germinans mangrove trees reaching 45 m high and 125 cm of trunk diameter. Combining structural descriptions of A. germinans trees found in both sites, I highlighted the site-specific differences in tree allometries. The study suggests that regional differences in mangrove tree structure and function could be captured through better description of crown metrics, and that selected indicators of local morphological plasticity and consequent stand structure could generate a plus-value in the understanding of mangrove stand dynamics across contrasting coastal environments. Beyond the extension of allometric models to large Avicennia trees, we proposed new biomass equations with improved predictive power when crown metrics is taken into account. Additionally, we developed a novel software tool, named Lollymangrove, based on the AMAPStudio suite of software, with the objective of maximizing the potential of further field descriptions and modeling works. Lollymangrove allows standardized forest data capture, 3D visualization of structural data, aboveground biomass computations from a configurable module and export formats for forest dynamics and remote sensing models. Simulation experiments were conducted by means of the spatially explicit, individual-based stand model BETTINA_IBM. This model describes the important mechanism of water uptake limited by salt stress, and revealed insights into the relation between environmental conditions, allometric variations and biomass partitioning of mangrove trees, and stand characteristics. The simulation results suggest close matches with observed ecological patterns (e.g., tree allometries, mortality distributions, and self-thinning trajectories) under higher salinity. In low salinity conditions, however, the current parameterization underestimates the maximum tree height and diameter, and consequently, aboveground biomass and self-thinning trajectories of forest stands. This suggests that the morphology of trees under low levels of salinity are explained by further regulation mechanism(s) that still need to be addressed in a subsequent model improvement. Overall, this work has essentially pointed out the need to elucidate how morphological plasticity relates with structural development of forest stands. It establishes that TLS measurements and structural data analysis associated to efforts for integrative software and mechanistic modelling works could link mangrove dynamics to fast-changing coastal processes.

Ecological network theory has developed from studies of static, binary trophic relationships to the analysis of quantitative, dynamic communities consisting of multiple link-types. Particularly, work has focused on the dynamic nature of ecological networks, which maintains stability in complex communities. However, there are few in situ network-level studies of the determinants of temporal and spatial variation in community structure. This thesis utilises data from a 10-year study of a host-parasitoid network and a collaborative study in an applied ecological setting to identify individual level factors important to network structure. The work aims towards an empirical, predictive framework linking adaptive foraging behaviour to ecological network structure. The results show that condition-dependent foraging behaviours structure host-parasitoid networks. The realised niches of the studied parasitoid species were generally biased towards larger host species and condition-dependent sex ratio allocation increased the likelihood that females would eclose from relatively larger hosts and males from relatively smaller hosts, which resulted in sex ratios deviating from Hamiltonian (50:50) predictions. Further, both of these aspects of behaviour are plastic, where parasitoid behaviour responded to environmental heterogeneity. Particularly, host preference behaviour conformed to an egg-/time-limitation framework, where the size dependency of the behaviour is greater when individuals have a greater likelihood of being egg-limited. Both the size-dependency and the plasticity of these behaviours differed significantly between secondary parasitoid species. This species identity effect interacted with landscape heterogeneity, which may explain some inter- and intra-specific variation in network structure. With respect to applied ecology, the results show that the benefits of natural vegetation for pest control are dependent upon the dispersal capabilities and the diet breadth of the pest and its natural enemies. The findings are evaluated towards a predictive framework for understanding the effects of future climate change on community structure and stability. We consider this framework in terms of applied ecology, particularly pest control ecosystem services provided by natural vegetation in an agricultural environment. The synergistic nature of the multiple determinants of network structure found in this thesis suggest that future studies should focus on the whole network, which is not necessarily the sum of its parts.

The determination of diatom species is mostly based on morphology of a silicified cell wall. It is complicated by the fact of cell diminution during the vegetative phase of the life cycle, which is conected with shape changes and loss of some taxonomically importat characters. Even though the diminution during the life cycle is generally known phenomeon, there is a lack of studies on this theme. In this masters thesis, four monoclonal populations of model pennate diatom strains were used in order to study shape dynamics during the life cycle. The strains were cultivated for almost three years and parts of the cultures with a different size stages were fixed in permanent preparations. The digital photographs of the cells were used as a material for the geometric morphometrics analyses. The study revealed high contribution of significant allometric changes to an overall shape variability. During the vegetative phase of the life cycle, disparity of the cells increases and complexity of the cells decreases. The contribution of symetric variability to an overall shape variability is more than eighty percent. Phenotypic plasticity in a monoclonal populations is an interesting finding from an evolutionary point of view. It may indicate constraints caused by the silica cell wall. During the size diminution...

Made available in DSpace on 2017-07-10T14:38:37Z (GMT). No. of bitstreams: 1 Salete de Paula.pdf: 1167747 bytes, checksum: 9705df79d28b7d3992e3d6910e9ce124 (MD5) Previous issue date: 2012-09-24 / Fundação Araucária / This study describes the development and allometric growth patterns of larval Piaractus mesopotamicus from induced reproduction. From hatching until the 19th day, twenty individuals were selected for eight stage of development (yolk sac larval, preflexion, initial of flexion, flexion, end of flexion and post flexion). Later, morphometric measurements were taken of each individual: total length, head length, trunk length, tail (post anal) length, head height, body height, muscle height at anus leveleye diameter, mouth length, caudal peduncle height and caudal peduncle length. Allometric growth coefficients were calculated by linear regression; the changes in the coefficients of growth relate to ontogenetic changes in the priorities of the larvae. During the developmental stages of larval yolk and pre-flexion (mean CT = 3.363 and 5.89 mm), the larvae showed an evident priority for feeding and swimming capabilities. From the flexion stage (mean CT = 9.33 mm) was observed a change in growth priorities, especially those relating to body height, important characteristic for this species. From the post-flexing stage (mean CT = 16.25 mm) a greater propensity to isometry was evident for all coefficients growths. These results confirm the informations that there are different growth patterns for priority functions during ontogeny initial larvae. This study of morphometric and allometric growth of larvae Piaractus mesopotamicus, may assist the fisheries biology, supporting management strategies and conservation of natural populations / Este estudo descreveu o desenvolvimento e os padrões de crescimento alométrico de larvas de Piaractus mesopotamicus provenientes de reprodução induzida. Desde a eclosão até o 19° dia, vinte indivíduos foram selecionados para oito estágios de desenvolvimento (larval vitelino, pré-flexão, início de flexão, flexão, final de flexão, início de pós-flexão, pós flexão e final de pós-flexão). Posteriormente, foram tomadas medidas morfométricas: comprimento da cabeça, comprimento do tronco, comprimento da cauda anal posterior, altura da cabeça, altura do corpo, altura do músculo em nível do ânus, diâmetro do olho, comprimento da boca, altura do pedúnculo caudal e comprimento do pedúnculo caudal. Os coeficientes de crescimento alométrico foram calculados por meio de regressões lineares; as alterações ocorridas nos coeficientes de crescimento referem-se as mudanças nas prioridades ontogenéticas das larvas. Durante os estágios de desenvolvimento de larval vitelino e pré-flexão (média CT= 3,36 e 5,89 mm) as larvas apresentaram uma evidente prioridade para as capacidades de alimentação e natação. A partir do estágio de flexão (média CT= 9,33 mm) foi observada uma mudança nas prioridades de crescimento, principalmente as relacionadas com a altura do corpo, característica importante para essa espécie. No estágio de pós-flexão (média CT=16,25 mm) uma propensão maior a isometria ficou evidente, para todos os coeficientes de crescimentos. Esses resultados confirmam as informações de que existem padrões diferenciados de crescimento para funções prioritárias durante a ontogenia inicial de larvas. Este estudo sobre morfometria e crescimento alométrico das larvas de Piaractus mesopotamicus, poderá auxiliar a biologia pesqueira, subsidiando as estratégias de manejo e conservação das populações naturais

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.

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