Top predators can have large effects on community and population dynamics but we still know relatively little about their roles in ecosystems and which biotic and abiotic factors potentially affect their behavioral patterns. Understanding the roles played by top predators is a pressing issue because many top predator populations around the world are declining rapidly yet we do not fully understand what the consequences of their potential extirpation could be for ecosystem structure and function. In addition, individual behavioral specialization is commonplace across many taxa, but studies of its prevalence, causes, and consequences in top predator populations are lacking. In this dissertation I investigated the movement, feeding patterns, and drivers and implications of individual specialization in an American alligator (Alligator mississippiensis) population inhabiting a dynamic subtropical estuary. I found that alligator movement and feeding behaviors in this population were largely regulated by a combination of biotic and abiotic factors that varied seasonally. I also found that the population consisted of individuals that displayed an extremely wide range of movement and feeding behaviors, indicating that individual specialization is potentially an important determinant of the varied roles of alligators in ecosystems. Ultimately, I found that assuming top predator populations consist of individuals that all behave in similar ways in terms of their feeding, movements, and potential roles in ecosystems is likely incorrect. As climate change and ecosystem restoration and conservation activities continue to affect top predator populations worldwide, individuals will likely respond in different and possibly unexpected ways.

Specialization and concentration of human activity is a phenomenon which accompanies the development of human settlements from their very beginning. While thoroughly explored in other fields, interconnection between pecialisation, on one hand, and urbanism and architecture, on the other, has been neglected. Nevertheless, this issue is of high ignificance since it determines the settlement structure development to a large extent. If understood correctly, this underlying principle of the impact of specialisation and concentration on the settlement development offers a new insight into historical context and enables one to understand the present development.

The remarkable diversity of plant-feeding insects could be explained by the dynamics of their plant associations, where host plant shifts and specialization onto a small fraction of available plants may promote diversification. Neotropical Adelpha butterflies contain a large number of species, and previous work indicated the colonization of a novel host plant family (Rubiaceae) fueled its rapid diversification. However, accumulating host records indicate wide taxonomic host breadth at family level and below. Here, we categorize Adelpha diet breadth based on known host plant relationships across the Neotropics and from Costa Rica, Ecuador and Brazil. We also use a diet breadth index that identifies plants used in similar ways by Adelpha, pointing to potential plant traits that could facilitate or prevent plant-insect interactions. We find that diet breadth in Adelpha is not likely to change at different geographic scales, and that regional resource specialization was uncommon. Additionally, the diversification fueled by the switch to Rubiacae, appears to have led to some lowland-clade Adelpha species specializing on a restricted subset of host genera and species within Rubiaceae, as well as in Urticaceae. In contrast, the A. serpa-group shows generalization, with each species tending to feed on its own set of several unrelated plant families. Taken together, these results indicate that Rubiaceae and additional plant families appear as important ecological factors that have promoted adaptations in Adelpha and host plant family-level switches have not always had the same effect on diversification, corroborating the importance of Rubiaceae for this butterfly genus. Further research involving detailed phylogenies is needed to investigate associations between changes in diet breadth and speciation events, and test hypotheses of diet evolution.

No description available.

Les champignons phytopathogènes sont des parasites majeurs des espèces végétales, autant naturelles que domestiquées. Botrytis cinerea, l’agent de la pourriture grise, en infecte plus de 1400 et est ainsi considéré comme un pathogène généraliste. Pourtant, des données récentes ont mis en évidence une structure des populations liée à leur hôte d’origine. Cette observation soulève l’hypothèse d’une spécialisation à l’hôte, à l’œuvre chez une espèce généraliste. Ce modèle d’étude pourrait permettre de faire avancer la connaissance des mécanismes évolutifs en jeu dans la divergence précoce des populations et la formation de nouvelles espèces fongiques. Cette thèse de doctorat a pour objectifs : (i) de démontrer formellement la spécialisation à l’hôte dans les populations de B. cinerea et d’en déterminer la magnitude et (ii) d’identifier les déterminants génomiques de cette spécialisation. Ainsi j’ai étudié la structure des populations par l’analyse de microsatellites d’un échantillon de 683 isolats, que nous avons corrélé à des tests de pathogénicité croisés sur différents hôtes. Ces travaux ont permis de mettre en évidence la spécialisation de B. cinerea aux hôtes tomate et vigne. En complément de ces lignées sélectionnées, l’espère Botrytis cinerea est constituée d’individus généralistes capables de coloniser les autres hôtes. Des méthodes d’inférence de structure et de généalogies sur des données de polymorphisme issues du séquençage de 32 individus nous ont permis de mieux définir la structure des populations ainsi que d’identifier une lignée spécialisée à la tomate. Enfin, des tests de McDonald-Kreitman et des méthodes de scans génomiques pour détecter des balayages sélectifs ont permis de mettre en évidence des gènes soumis à la sélection divergente entre les populations spécialisées, révélant de possibles déterminants de cette spécialisation. Ces travaux sont ainsi une base pour la validation de plusieurs gènes impliqués dans la pathogénicité hôte-spécifique de B. cinerea, et ouvrent la voie à des améliorations de la gestion du réservoir d’hôtes et des pratiques culturales contre la pourriture grise. / Phytopathogenic fungi are major parasites to wild or domesticated plant species. The grey mold fungus, Botrytis cinerea, infects more than 1400 plant species and thus is considered a broad generalist. However, recent data have revealed population structure correlated to the host of origin of isolates. This observation raises the hypothesis of ongoing host specialization in a generalist species. Studying this question could greatly deepen our theoretical knowledge of the evolutionary mechanisms involved in the early stages of population divergence and subsequent speciation. This thesis aims (i) to formally demonstrate the host specialization in B. cinerea’s populations and determine its magnitude, and (ii) to identify the genomic determinants of this specialization. Thus, I studied population structure based on 683 isolates characterized using microsatellite markers. We compared the inferred genetic structure with variations in aggressiveness measured through cross-pathogenicity tests on multiple hosts. These experiments and analyses confirmed the specialization of B. cinerea to tomato and grapevine hosts. Besides these specialized lineages, the species B. cinerea is composed of generalist individuals capable of infecting multiple hosts. I sequenced the whole genome of 32 individuals and characterized nucleotide polymorphism. Structure inference and genomic genealogy methods allowed us to more accurately define the population structure and identify a lineage specialized on tomato. Lastly, McDonald-Kreitman tests and genomic scans methods allowed the identification of genes under divergent natural selection between populations, revealing possible genomic determinants of specialization. This work can serve as foundation for the validation of multiple genes involved in host-specific pathogenicity of B. cinerea, and pave the way for the implementation of efficient strategies for managing pathogen reservoirs and new agricultural practices for controlling grey mold.

Title: Different approches and their impact on musculosceletal system of tennis players. Objectives: The central aim of master thesis was the comparison of flexibility and agility of Norwegian tennis players and tennnis players from Czech Republic at the competitive level. The comparsion was respecting and taking into consideration apllied compensatory program which was a building part of the study. The another aim was to aquire information regarding training preparation of tennis players from Norway and their comparison to training preparation of Czech players. Methods: Thesis is an quasi-experimental study. In the beginning and the end of this study all players underwent the opening and final measurments of flexibilty and agility. Final measurements were done after five days of intervetion with emphasis on unilateral load compensation. Intervetion contained predominantly flexibility and agility exercises. The specialized questionarre was filled by trainers of Oslo Tennis Club, chosen trainers from all around the Czech Republic and ten professional tennis players from Czech national team. Obtained data were analysed using statistic methods. Results: The firts hypothesis assuming statistically more significant data from opening flexibility measurments of Norwegian players compared to Czech players...

This thesis Specialization of American football players in relation to their somatotype deals with the differences in somatotypes of American football players in the Czech Republic. Its main aim is to describe the somatotypes of American football players from the side of their player specialization and their participation in the 1st and 2nd league of American football in the Czech Republic. For successful achievement of the main aim are defined partial aims of the thesis, which are primarily to find out the somatotypes of players of all specializations and then to compare these somatotypes from different perspectives. The whole purpose of this description of somatotypes is mainly to identify the role of somatotype on differentiation of players in individual game positions. The sample of this work is made up of 70 probands located across all players' specializations in the 1st and 2nd league of American football in the Czech Republic. Somatic measurements of parameters necessary to determine their somatotypes were used on all subjects. The measured values were processed and statistically analyzed through calculations and spreadsheets in Microsoft Excel and through somatocharts. The results of this thesis show us somatotypes of players of all specializations, but also differences between somatotypes...

Cuckoo bees behave similarly to the well-known birds, cuckoos - they lay eggs in the nests of other bees. Proposed thesis charts the evolution of host specialization within the strictly cuckoo genus Sphecodes. According to the classical view based on the Red Queen hypothesis, parasites should gradually specialize during evolution to keep pace in the "arms race" with their hosts. Specialization is also perceived as an evolutionary dead end - narrow adaptation prevents change of host. To test these hypotheses phylogeny of tribus Sphecodini based on the partial sequences of five genes was constructed. For each ancestor has been by two methods of mapping ancestral characters (Bayesian method, Maximum Parsimony) specified, whether it was specialist or generalist and which kind of host or hosts it had. The results show that the original strategy of genus Sphecodes is specialization and generalists originated from specialized ancestors only recently. The results also show that the jumps between the hosts are common. These findings are inconsistent with the Red Queen hypothesis as well as with the view that specialization is an evolutionary dead end. Falsity of these hypotheses within the genus Sphecodes established also likelihood ratio test, in which the likelihood of model allowing two-way transition...

No description available.

This study explored how recreation specialization and different types of motivations were related to environmental settings preferred by backcountry hikers. A questionnaire was developed that measured the level of hiking specialization, desired psychological outcomes, and preferred environmental setting attributes. Ouestionnaires were mailed to 619 backcountry hikers from three Intermountain West hiking areas; a response rate of 68 percent was attained. Results of the study revealed significant associations between the level of hiking specialization and the psychological states desired by backcountry hikers. In general, increased hiking specialization served to increase the importance of specific psycholoqical outcomes such as autonomy, exercise, achievement and nature. Significant associations were also found between the level of hiking specialization and the types of environmental settings preferred by hikers. Hiking specialization exhibited significant relationships with 55 percent of the studied environmental setting attributes, especially within the physical and managerial setting domains. The five study motives were especially adept at explaining the physical setting attributes desired by hikers, but lacked predictive power in explaining preferences for managerial settings. The final study analysis utilized two canonical correlation analyses to allow the specialization and motive variables to be combined as a set of independent variables to see which combinations would emerge as important predictors. The specialization variable emerged in both canonical analyses as the first and dominant indicator of the setting attributes. Additional interpretations of the canonical results indicated that two motive-based orientations to backcountry hiking may exist. The findings of this study have implications for researchers and managers seeking to understand why environmental settings are valued differently by recreationists, even within the same activity style. Secondly, researchers studying recreation motivation could utilize recreation specialization as a useful developmental framework for explaining differences in motivational states over time. The results also imply that management strategies sensitive to changes in levels of recreation specialization may be less costly in dollars and offer a more precise way of defining the diversity of opportunity and settings sought by recreationists.