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Vliv pachové preference na reprodukční úspěch u hraboše polního
BÍLKOVÁ, Pavlína
The aim of this work is to find out whether odor preference can affect the reproductive success of voles. Odors are generally able to reveal a lot of information about his carrier, according to which individuals may be able to choose a more compatible partner. With this partner, they increase the probability of transferring good genes to their offspring. The more investing sex is the one he chooses, and for most species it is the females. In the T-labyrinth, we gave the females a choice of odors from two males and, according to the time spent with one or the other, we evaluated the preference for one of them using a monitoring program. The females were then paired with either the male they preferred or the male they did not prefer. The number of pups from each pair was the main indicator for evaluating our results. These show that female voles are able to choose a more suitable partner according to their smell, with whom they produce more offspring.
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The association between tail streamer length and male atractiveness in barn swallows
Záleská, Josefína ; Albrecht, Tomáš (advisor) ; Cepák, Jaroslav (referee)
In the view of the sexual selection research, the barn swallow (Hirundo rustica), and its European subspecies (Hirundo rustica rustica) in particular, belongs to the most detailed studied bird species all over. The males of the European subspecies have in general markedly longer outer tail streamers than the females have and, based on research in several European populations, this tail ornamental trait plays an important role in sexual selection in this subspecies. The length of the tail streamers was found to be related to several main parameters that are connected to individual attractiveness in socially monogamous pairing systems, such as early partner acquisition and earlier nesting initiation date, the probability of repeated nestings in a breeding season or the number of successfully raised young. The main aim of the presented diploma theses is to assess to what extend is the length of the tail streamers a determinative trait related to male attractiveness in a South Bohemian population of the European barn swallow. The results of this thesis imply that the tail streamer length of males is, indeed, an attractive trait in this population, connected to multiple mating advantages. KEY WORDS Sexual dimorphism, sexual selection, barn swallow, nesting initiation, attractivity, reproductive success,...
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Changes in pollinator behaviour under different plant spatial aggregation
Štenc, Jakub ; Janovský, Zdeněk (advisor) ; Bartoš, Michael (referee)
Plants often occur aggregated into clusters and this spatial pattern is supposed to affect pollinator behaviour and pollen dispersal. Such pollinator reaction may influence reproductive success of zoogamous plant species both in terms of number of available mates and their genetic diversity (nearby growing plant individuals are also often closely related, especially in clonal plants). In the present thesis, I investigated the influence of plant spatial aggregation on pollinator behaviour and how this translates into pollen transfer. For that purpose, I carried three experiments. In the Experiment 1, I used potted plants placed into arrays and aggregated into four patches in order to track the pollen dispersal by means of a UV-dye pollen analogue. I manipulated distances between plants within clusters (dense × loose) and between clusters (near × far). I conducted this experiment for three plant species differing in their pollinator spectra. In the Experiment 2, I observed pollinator foraging sequences (sequences of visited plant individuals) under the same experimental design as for the first experiment, but I carried out this experiment for five plant species. In addition in one study species, Dianthus carthusianorum, I conducted the Experiment 3 to get better insight into pollination effectiveness...
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Assortative mating in humans.
Štěrbová, Zuzana ; Weiss, Petr (advisor) ; Lindová, Jitka (referee) ; Špinka, Marek (referee)
Human mate choice is far from random. Assortative mating can be either positive (homogamy), when people prefer and choose partners with self-similar characteristics, or negative (heterogamy, complementarity), when people prefer self-dissimilar partners. Over one hundred years of research, it has been shown that people generally couple based on the principle of homogamy. This thesis seeks to address the following two goals. First, it critically reviews the current state of knowledge in positive assortative mating (in particular, empirical support, factors affecting homogamy, mechanisms of homogamy, relationship and genetic impact of homogamy, and methodological pitfalls of research). This section includes theoretical papers deal with further mechanisms of assortative mating (homogamy, imprinting-like effect, heterogamy, complementarity). Second, the thesis provides further test of assortative mating in 'ideal partners' (preferences) and actual partners, in the context of sex, sexual orientation (heterosexual and non-heterosexual), and population (Brazil and Czech Republic). Results of these studies show that the principle of homogamy is valid irrespective of sex and population. However, they find a stronger tendency for homogamy in actual partners among heterosexuals than in homosexuals, although...
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Changes in pollinator behaviour under different plant spatial aggregation
Štenc, Jakub ; Janovský, Zdeněk (advisor) ; Bartoš, Michael (referee)
Plants often occur aggregated into clusters and this spatial pattern is supposed to affect pollinator behaviour and pollen dispersal. Such pollinator reaction may influence reproductive success of zoogamous plant species both in terms of number of available mates and their genetic diversity (nearby growing plant individuals are also often closely related, especially in clonal plants). In the present thesis, I investigated the influence of plant spatial aggregation on pollinator behaviour and how this translates into pollen transfer. For that purpose, I carried three experiments. In the Experiment 1, I used potted plants placed into arrays and aggregated into four patches in order to track the pollen dispersal by means of a UV-dye pollen analogue. I manipulated distances between plants within clusters (dense × loose) and between clusters (near × far). I conducted this experiment for three plant species differing in their pollinator spectra. In the Experiment 2, I observed pollinator foraging sequences (sequences of visited plant individuals) under the same experimental design as for the first experiment, but I carried out this experiment for five plant species. In addition in one study species, Dianthus carthusianorum, I conducted the Experiment 3 to get better insight into pollination effectiveness...
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The strength of minority cytotype disadvantage in plant populations consisting of diploid and polyploid individuals
Pilneyová, Markéta ; Čertner, Martin (advisor) ; Chrtek, Jindřich (referee)
Mixed-ploidy populations, consisting of multiple cytotypes, are an optimal system for studying genome doubling consequences in plants. The role of frequency dependent selection, known as minority cytotype exclusion principle, is very important in them, but there are many factors limiting this selection. In my thesis, I evaluate the changes in cytotype frequencies and pattern in permanent plots in natural mixed-ploidy populations of three plant species - Butomus umbellatus, Knautia serpentinicola and Tripleurospermum inodorum and I also experimentally analyze partial aspects of frequency dependent selection towards minority cytotype in artificially established mixed-ploidy arrays of two plant species - Arabidopsis arenosa and Tripleurospermum inodorum. Varied changes in frequencies of minority cytotype ware revealed in permanent plots. Usually there was decrease, but in two plots there was increase in minority cytotype frequency and in one case it became dominant. Observed changes depend on initial frequencies of minority cytotype in populations, biological properties of species and particular environment of permanent plot. Relative indexes describing the frequency and the strength of disturbances and also the amount of soil nutrients was used to compare the environment of permanent plots across...
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Cytotype coexistence in plant populations, its mechanisms and temporal perspectives
Pilneyová, Markéta ; Čertner, Martin (advisor) ; Ptáček, Jan (referee)
Mixed-ploidy populations, consisting of multiple cytotypes, are an optimal model system for studying the consequences of genome doubling in plants. By comparing the polyploids with their diploid ancestors, we can discover the changes caused by polyploidization on both individual and population levels as well as understand the role polyploidization plays in plant evolution. In my thesis, I address the mechanisms affecting the coexistence of multiple cytotypes in mixed-ploidy populations. Minority cytotype exclusion principle and different breeding barriers between cytotypes (cytotype segregation, flowering phenology, pollinator fidelity, autogamy, gametophyte competition, triploid block) along with the effect of environment (disturbance, migration) on mixed-ploidy populations are described in this thesis. Particularly, I focus on the temporal persistence of mixed-ploidy populations due to its crucial role for our understanding of the polyploidization as an important evolutionary process.
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Mechanisms of assortative mating in humans
Dudková, Tamara ; Havlíček, Jan (advisor) ; Bártová, Klára (referee)
Two main principles of the relationship formation were previously established: i) homogamy and ii) heterogamy. According to the principle of homogamy, partners tend to be similar to each other. In contrast, heterogamy states that partners' characteristics differ. The theory of homogamy has reached significantly higher empirical support, however it is still unclear which mechanisms lead to similarities between partners. Potential mechanisms involve proximity (geography and social propinquity/proximity), preference for self-similarity, convergence (mutual assimilation) during cohabitation etc. Several previous studies showed, the similarity between partners in various social-demographic, physical, and attitudinal characteristics among others contributes to the relationship satisfaction. The main aim of the proposed bachelor thesis, is to perform a review of the relevant literature and analyse which mechanisms of homogamy and heterogamy apply to various characteristics and whether their role vary according to the type of the relationship (i.e. open relationships, marriages, etc.)
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