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Flight initiation distances and life histories in birds: comparison of intra- and interspecific approaches
Brzobohatá, Tereza ; Albrecht, Tomáš (advisor) ; Klvaňa, Petr (referee)
Information about the distance, in which the birds flee from predators, may help us to better understand avian escape behavior and stress responses. These distances are influenced by many life-history traits and related factors, both on intraspecific and interspecific levels. This bachelor's thesis is trying to summarize the current knowledge of agents influencing flight initiation distances (FID) of birds, in the form of a literary research. The first section deals with antipredator behavior in birds, and explains methods that are used for measuring critical distances. In the second part of thesis, factors affecting flight initiation distances on intraspecific level are described. The main emphasis is on impact of age characteristics, body sizes, reproductive investments and geographical distribution. The last chapter summarizes the information about relationships between FID and life-history traits on interspecific level. The age of the individual, levels of stress hormones, the effect of the season and biotop are described in detail. Powered by TCPDF (www.tcpdf.org)
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Sperm competition in birds and causes for its intra- and iterspecific variation
Šplíchalová, Petra ; Albrecht, Tomáš (advisor) ; Poláková, Radka (referee)
This bachelor thesis focuses on describing the occurrence and within- and between species variation of extra-pair paternity (EPP) in socially monogamous birds. In the first part of thesis I discribe variation in EPP levels among birds - I identify species with no EPP ever recorded, and species with extreme values of EPP. Extra-pair paternity seems to be more common in passerines than non-passerines. In the second part of my thesis, the most influential correlates of EPP levels in passerine birds are discussed. I summarize contemporary knowledge of the effect of these (mostly ecological) factors on EPP. These include breeding density and synchrony, population genetic diversity, adult mortality and longevity and male contribution to parental care. Key words: promiscuity, extar-pair paternity, extra-pair copulations, sperm competition
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Acoustic and visual signalization in birds: Identification of key components and their role in sexual selection
Mikula, Peter ; Albrecht, Tomáš (advisor) ; Svobodová, Jana (referee)
This bachelor thesis is focused on describing visual and acoustic signals in birds and their potential role in the process of sexual selection. Evidence that acoustic and visual signals are sexualy selected is summarized. The key characters that can be utilized in comparative studies are determined. In the first chapter of the thesis are briefly outlined mechanisms of sexual selection and evolution of costly secondary male ornamentation. In the second chapter basic avian ornaments (colouration, acoustic signals) are described. The emphasis is on visual and acoustic structures which are costly to produce and serve as honest indicators of individual condition. The third chapter is devoted to the possible trade-offs between visual and acoustic signalization in birds. The last section summarizes hypotheses about potential relationships between visual and acoustic signalization (and trade-offs between these two types of ornamental traits) in relation to changing environmental conditions.
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Investment in reproduction and nest defense in waterfowl
Javůrková, Veronika ; Albrecht, Tomáš (advisor) ; Remeš, Vladimír (referee) ; Weidinger, Karel (referee)
Investment in reproduction is considered to be crucial component of life history traits. Reproductive success is however constrained by generally unpredictable environmental conditions. Based on "bet hedging" theory, individuals are forced to eliminate such unpredictability via the mixed strategy to maximize their long-term fitness. Predation represents underlying factor affecting individual reproductive success, and it undoubtedly lies behind the evolution of alternative reproductive strategies such as extra-pair paternity and conspecific brood parasitism. Behavioral mechanisms related to nest defense are thought to be investment in reproduction in accordance with trade-off between actual and residual reproductive value. Despite the extensive interest in the principles associated with parental investment into the nest defense, studies describing in detail the pattern of particular antipredator strategies are rare. Similarly, mechanisms responsible for maintenance of egg- viability during prolonged egg-laying period in species delayed the onset of incubation are poorly understood. In accordance with mentioned themes, this thesis includes publications aimed at aspects of reproductive biology and antipredator behavior in Mallards (Anas platyrhynchos). Particular publications concretely documented: a)...
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Male quality, extrapair paternity and parental investments in scarlet rosefinches
Schnitzer, Jan ; Albrecht, Tomáš (advisor) ; Fuchs, Roman (referee) ; Šálek, Miroslav (referee)
Social monogamy, closely associated with bi-parental care, is the most frequent pairing system found in birds. Because females invest more into the reproduction, they are usually considered to be the sex that chooses the partner. To satisfy female preferences in the mate choice males in various species developed a number of traits that signalize their quality. What qualities are signaled by these traits and what mechanisms are responsible for the emergence, development and maintenance of these traits is the subject of a number of evolutionary- ecological studies. By pairing with an appropriate male female can obtain direct or indirect benefits to its own fitness. The good parent theory suggests that male secondary sexual traits signalize male ability to provide parental care (a direct benefit). An indirect benefit is presented by the quality of the genetic material that the female obtains from male for her offspring. According to the good genes hypothesis females use secondary male ornamentation to assess genetic quality of males. One of the most studied secondary sexual ornaments that can advertise male quality and may be used in mate choice by females is the plumage colouration. In many avian species there is sexual dimorphism in the plumage colouration and there is also growing evidence that...
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Vliv stavu a funkce imunitního systému na pohlavní výběr u ptáků
Vinkler, Michal ; Albrecht, Tomáš (advisor) ; Kleven, Oddmund (referee) ; Grim, Tomáš (referee)
Evolution is a most fascinating feature of all living things in our world. The means of organismal evolution are diverse, comprising mainly of natural and sexual selection. Both of these phenomena may contribute to evolutionary adaptations in health and disease. The questions of immunity impact on the process of sexual selection and sexual selection for increased anti-parasite resistance are wide issues of the present research in natural sciences. Their clarification requires multidisciplinarily-based investigation combining a variety of partial results into a single united paradigm. My co-workers and I have chosen several specific issues to study, in order to fill some of the important gaps of the current knowledge. We proposed the Carotenoid maintenance handicap hypothesis to point out that optimisation instead of maximisation of the carotenoid intake and ornamental display may be physiologically convenient for the individual. In Scarlet rosefinch (Carpodacus erythrinus) we confirmed the role of the carotenoid-based ornamental colouration in the process of sexual selection and investigated several partial aspects of the association between immunogenetics, immune function, health and the ornament expression and mate choice. In Zebra finch (Taeniopygia guttata) we have shown that the present way of...
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Effects of olfaction and visual stimuli on mate choice decisions in Grey Partridges
Kotasová, Kateřina ; Albrecht, Tomáš (advisor) ; Sedláček, Ondřej (referee)
This theses focuses on olfactory and visual components of mate choice in grey partridge. The aim is to evaluate the importance of melanin-based ornametnation and olfaction in mate choice and to explain the role of sexual selection in the evolution of secondary ornamentation in this socially monogamous galliform bird. To do that several experiments were conducted to (1) assess the ability of individuals to recognize conspecific odour and (2) to estimate the significance of melanin based feather ornamentation in male-male and male-female interactions. In some experiments I manipulated the expression (size) of feather maleanin- based ornamentation while in others I used birds forced to pair randomly to find out how the size of ornament and similarity in ornament expression between males and females (assortative pairing) affects reproductive success and investments (egg hatchability and number of eggs laid).
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Productivity of environment and colouration of South African birds
Kubíková, Tereza ; Hořák, David (advisor) ; Albrecht, Tomáš (referee)
Understanding the relationships between species traits and the environment is essential for assessment of functional diversity. The variation in avian plumage colouration has attracted much scientific attention for a long time. It is thought that the colouration of birds is a product of interaction between environmental and sexual selection forces. Using two complementary three-matrix approaches (fourth-corner and RLQ analyses) I investigate geographical variation in plumage colouration of birds living along environmental gradient of productivity in South Africa. I suppose that productivity of environment could explain the part of variation in colouration of species at large geographical scales. I compiled information about 14 plumage traits for 649 species. Co- inertia analysis revealed that more vari-coloured species (e.g. with more saturated and vivid plumage), species with carotenoids in feather, blue-green or predominantly black species occur mainly in productive habitats such as moist savannas and woodlands in the north-east of the country. On the contrary pale species (e.g. greyishbrown), whose feathers are brighter (have higher values of brightness), occupy arid habitats in the west. It shows that another pattern such as iridescence, sexual dimorphism and brightness of particular body region exhibit...
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Condition dependence of secondary ornamentation and mate choice in Grey Partridges
Gabrielová, Barbora ; Albrecht, Tomáš (advisor) ; Sedláček, Ondřej (referee)
This study focuses on relationships between individual condition, measures of ornament expression and mate choice in the Grey Partridge (Perdix perdix). It is based on the correlative data as well as results of manipulative experiments. I found positive correlation between the size of melanin- and carotenoid-based ornaments in partridges. The size and the redness of the carotenoid skin patch, and the size of the melanin-based feather ornamentation were associated with several measures of immunity and overall body condition (complement activity, ratio of immature erythrocytes, heterophil/leucocyte ratio, response to novel antigen). Furthermore, data from natural populations indicate that the expression of carotenoid-based ornamentation is associated with sexual attractiveness (measured as the ability to obtain a social mate) in partridges. Data from captive individuals indicate that carotenoid supplementation improves the redness of carotenoid-based ornament, while the stimulation of the immune system under increasing concentrations of supplemented carotenoids has no measurable effect on condition and physiological state. This seems to contradict predictions of the 'Carotenoid maintenance hypothesis'. Overall, results better understanding the role of carotenoid and melanin-based ornamentation in signaling...
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