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Macroecology and macroevolution of birdsong
Mikula, Peter ; Albrecht, Tomáš (advisor) ; Osiejuk, Tomasz S. (referee) ; Šálek, Miroslav (referee)
Birdsong is one of the most astounding natural sounds which profoundly shaped our evolutionary thinking since the 19th century. Despite a strong interest in birdsong for over 100 years, our understanding of birdsong ecology and evolution over large spatial and phylogenetic scales is still very fragmentary. Answering many basic questions requires a global synthesis covering vast diversity of extant bird species and adoption of multidisciplinary approaches. In presented dissertation thesis, my co-workers and I have explored important patterns in macroecology and macroevolution of song in passerines (Order: Passeriformes), the most diverse and widespread bird order. We have focused on three key song phenomena: (1) song complexity, (2) song frequency and (3) the presence of song in female birds. We have exploited birdsong "big data" available on public citizen science databases and other open sources in order to fill several important gaps in the current knowledge. These data were analysed by a combination of phylogenetically-informed cross-species analyses and spatial macroecological approaches. Since the publication of Darwin's seminal work, elaborated songs are generally agreed to be the result of sexual selection. We developed a simple but reliable song complexity metric to explore a global diversity in...
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Reproductive tactic of the Common Pochard (Aythya ferina)
Hořák, David ; Albrecht, Tomáš (advisor) ; Grim, Tomáš (referee) ; Honza, Marcel (referee)
Reproductive tactic of the Common Pochard (Aythya ferina) David Hořák Summary of the PhD. thesis Capability of reproduction is a fundamental characteristic of all living systems. "Desire" for it is, according to modem evolutionary theories, a motive force of majority of events in the living world. Every organism competes for the possibility to reproduce with the aim to have as many viable offspring as possible during an individual's life time. The way in which they cope with changing environment athacts the attention of many biologists. The evolutionary adjusting to environmental conditions or set ofanatomical, physiological and behavioural adaptationsis called life history. To puzzle out the life histories seems to be a challenge and we try to understandthem using description oftheir characteristics(life history traits).Those are most frequently number and size of offspring, body size, number of reproductive events in a life time or lifespan. There is a lot of life history traits. Combinations of their diverse stateslay in the background ofgreat number oflife histories. Birds serve as suitable models for life history investigation because their life cycle as well as reproductive event is properly separated into distinct parts and investment into reproduction can be quantified easily. This thesis focuses on...
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Alternative reproductive strategies and sexual selection in barn swallow Hirundo rustica
Michálková, Romana ; Albrecht, Tomáš (advisor) ; Sedláček, Ondřej (referee) ; Svobodová, Jana (referee)
Molecular techniques have revealed that avian mating system is more diverse and complex than previously thought. Both males and females can use alternative reproductive tactics to increase their fitness. Here, we have determined the prevalence of conspecific brood parasitism (CBP, 22% of nests), quasi-parasitism (QP, 6.5% of nests) and extra-pair paternity (EPP, 51.2% of nests) in European subspecies of barn swallow (Hirundo rustica rustica). In contrast to EPP and CBP, QP is rare and has been described in only a few bird species. Our data indicate nonrandom QP patterns, suggesting that this tactic can be considered a third alternative reproductive strategy, alongside CBP and EPP. Sexual ornaments are usually assumed to evolve as condition-dependent signals of individual quality. In this context, a positive correlation between the expression of ornamental traits and survival, is expected. Evolutionary theory predicts that females seek extra-pair fertilizations from high-quality (more ornamented) males and EPP has consequently been proposed as a principal protagonist in the evolution of male secondary sexual traits, however empirical evidence in support of the assertion is relatively scarce. Despite decades of research into the role of EPP in sexual selection, the potential fitness advantages for...
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Exaggerated male tail length and sexual selection in birds
Záleská, Josefína ; Albrecht, Tomáš (advisor) ; Klvaňová, Alena (referee)
Elongated tail feathers and tail coverts of birds are used as a textbook example of exaggerated secondary sexual characters evolved through sexual selection via female choice. The female tendency to prefer males with the most elaborate ornaments can be explained on the basis of a positive genetic correlation between the preference and the ornament. Alternatively, an elaborated ornament can indicate good quality and heritable viability of the male and therefore, choosing the most ornamented male, the female chooses for "good genes" for her offsprings. Sexual ornaments can impose negative effects on a different aspect of the individual's life. The compensation for these disadvantages should be enhanced reproductive success of the ornamented males. This thesis aims to summarize main findings of the role of elongated tail feathers in sexual selection in birds, concerning their effects on viability and atractivity of males in different mating systems. It provides an illustrating overview of the occurrence of elongated tail feathers in birds, and puts together available evidence of fitness benefits associated with elongated tail feathers in males. Despite a pervasive interest in the signalling function of tail feather ornaments in birds, most research focuses on only a few model taxa, with often...
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Macroecology and macroevolution of birdsong
Mikula, Peter ; Albrecht, Tomáš (advisor) ; Osiejuk, Tomasz S. (referee) ; Šálek, Miroslav (referee)
Birdsong is one of the most astounding natural sounds which profoundly shaped our evolutionary thinking since the 19th century. Despite a strong interest in birdsong for over 100 years, our understanding of birdsong ecology and evolution over large spatial and phylogenetic scales is still very fragmentary. Answering many basic questions requires a global synthesis covering vast diversity of extant bird species and adoption of multidisciplinary approaches. In presented dissertation thesis, my co-workers and I have explored important patterns in macroecology and macroevolution of song in passerines (Order: Passeriformes), the most diverse and widespread bird order. We have focused on three key song phenomena: (1) song complexity, (2) song frequency and (3) the presence of song in female birds. We have exploited birdsong "big data" available on public citizen science databases and other open sources in order to fill several important gaps in the current knowledge. These data were analysed by a combination of phylogenetically-informed cross-species analyses and spatial macroecological approaches. Since the publication of Darwin's seminal work, elaborated songs are generally agreed to be the result of sexual selection. We developed a simple but reliable song complexity metric to explore a global diversity in...
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Significance of predation for breeding ecology and conservation in shorebirds
Kubelka, Vojtěch ; Šálek, Miroslav (advisor) ; Albrecht, Tomáš (referee) ; Hötker, Hermann (referee)
Predation is the most common cause of reproduction failure and it strongly influences breeding performance in birds, impacting the whole species population dynamics as well as it represents a major force in the evolution of avian life-history strategies. Investigating the factors driving predation rates, or quantifying predation consequences, is highly relevant for evolutionary ecology as well as for species conservation, especially in a rapidly changing world. In this dissertation, I investigate links between nest and chick predation, environmental factors, life-history and anti-predatory strategies, together with consequences for population dynamics and conservation. I use shorebirds as a uniquely suitable model system for three reasons: i) they are globally distributed; ii) have predominant ground nesting strategy and high interspecific similarity in nest appearance to potential predators; iii) are sufficiently well- studied in terms of nest predation all over the world. In the two first sections of this dissertation, Predation in the agricultural landscape and Interspecific interactions and anti-predatory strategies, Chapter 2 supports the thermoregulatory hypothesis of nest lining size rather than anti-predatory adaptation. Chapter 3 discusses, from the perspective of predation, the twofold...
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Latitudinal and altitudinal trends in sperm morphology and estimated levels of promiscuity in passerine birds
Krejčířová, Zuzana ; Albrecht, Tomáš (advisor) ; Sedláček, Ondřej (referee)
Sexual promiscuity, whereby females copulate with more than one male, is a quite common phenomenon in socially monogamous birds, and especially in songbirds. This behavior is assumed to influence the evolution of various anatomical traits associated with male ability to outcompete other males in the process of sperm competition. High promiscuity is, in a multi- species comparison, associated with higher relative testis mass, but may also affect sperm phenotypes and other male phenotypes. Sperm morphology is clearly differentiated across avian species and some studies suggest that stabilizing post-copulatory selection on sperm length is responsible for a clear association of between male variation in sperm length and levels of promiscuity. However, the association between other phenotypic traits and promiscuity remains less clear. In this study, I focus on sperm characteristics in relation to the estimated levels of promiscuity in songbirds of tropical and temperate zone climates, and across an altitudinal gradient in the tropics. I found that the coefficient of variation in sperm length, both between males (CVbm) and within males (CVwm), was indeed a good index of promiscuity. I also reveal the size of cloacal protuberance as an anatomical trait intimately associated with the level of sperm...
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Ornament expression and lifetime reproductive success in male barn swallows (Hirundo rustica)
Wnuková, Lucie ; Albrecht, Tomáš (advisor) ; Klvaňová, Alena (referee)
Within a lifetime of an individual, there are changes in the organism leading to an an impairment of phenotype, survival and reproduction. The expression of phenotypic traits often increases with age. Higher expression of these traits in the young age can lead to decreased probability of survival till the next season, influencing reproductive success of an individual. That is why organisms are challenged with trade-offs, when they have to allocate their limited resources either into the reproduction in form of expression of extravagant sex ornaments or into the life span. If the ornament evolved as a handicap, its exaggerated size could reduce viability of low quality individuals. Therefore, the ornament becomes a predictor of quality of its bearer and its size indicates the ability to survive till the next season. Both sexual ornamentation and inter-individual variation in life span may result in differences in reproductive success (fitness) and targeted by sexual or natural selection. Variability in reproductive success, mainly in monogamous species, can be increased also by sexual promiscuity and extra-pair mating and extra-pair copulations. This strategy can increase the opportunity for selection of traits that play role in choosing of extra-pair mate. In this work, I focused on two potential...
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Latitudinal trend in feather growth rates and steroid hormone concentrations in avian feathers
Brzobohatá, Tereza ; Albrecht, Tomáš (advisor) ; Sedláček, Ondřej (referee)
Avian life histories range along the axis from slow to fast, with slow life histories being characterized by greater investments in future reproduction, and fast by greater investments in current reproduction. The concept of pace-of-life syndromes refers to the coevolution of life strategies and related physiological, immunological and behavioral traits. Avian species from tropical areas are characterised by slower life histories (longer parental care, later maturation, smaller clutches, reduced metabolic rate) when compared to temperate zone species. Within this latitudinal gradient, investments in the total amount (weight) of body feathers have also been shown to be reduced in tropical birds. It remains unclear, however, whether feather growth itself follows this latitudinal pattern, and is slower in tropical species. Tropical birds have lower basal levels of corticosterone and testosterone, however available studies are based mainly on analyzes of hormone concentrations from plasma. The first aim of this diploma thesis was to evaluate differences between tropical (Cameroon) and temperate zone (the Czech Republic) passerine species in investments in tail feather growth by using methods of comparative ptilochronology. The second aim of the diploma thesis was to analyze concentrations of steroid...
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Postcopulatory sexual selection on phenotypic traits in European barn swallows
Míčková, Kristýna ; Albrecht, Tomáš (advisor) ; Svobodová, Jana (referee)
Sperm phenotype is an essential indicator of the male ejaculate quality and may have a significant impact on male reproductive success. Sperm phenotypes are considerably variable across species but variation is also found among males within species. This thesis examines (1) variation in sperm phenotypes among males in barn swallows (Hirundo rustica), (2) changes in male ejaculate quality with age, (3) relationships between sperm morphology and motility, (4) effects of sperm phenotypes (morphology and motility) on male fertilization success, using a large dataset of 174 observation for 130 males, and (5) the influence of female reproductive environment on sperm motility. From the tested variables, only midpiece length correlated with male age. Older males had shorter midpiece but no relationship between male age and reproductive success was found. Sperm length negatively affected sperm motility and, simultaneosly, relative midpiece length posively correlated with sperm motility. No correlation was found between the male reproductive success and sperm motility, presence of abnormalities, length of outermost tail feathers or age. Males with shorter relative midpiece were more successful in within-pair paternity, and males with shorter sperms but longer relative midpiece were more successful in...
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