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Extra-pair fertilizations and the opportunity for sexual selection in Barn swallows
Michálková, Romana ; Albrecht, Tomáš (advisor) ; Šálek, Miroslav (referee)
Generally it is assumed, that sexual selection drives the evolution of elaborate traits. The strength of sexual selection has traditionally been attributed to varinace in reproductive success among individuals. This variance is mainly caused by the number of mating partners and the number of sired offspring. Both males and females can increase their reproductive success by alternative reproductive strategies - extrapair copulations and intraspecific brood parasitism. In our study we tested the relationship between male ornamentation and success in extra-pair and within-pair paternity and the total male reproductive success in barn swallow (Hirundo rustica), a socially monogamous species with high levels of extrapair paternity. The results suggest more colourful throat to indicate male reproductive success. Dark rusty males were less often cuckolded and they have higher total fertilization success than drab ones. Tail length did not affect neither within- nor extra-pair fertilization success, however, previous studies have concluded that reproductive success of male barn swallows is positively related to the tail ornaments. Our results confirm that extra-pair paternity considerably increase variance in reproductive success among barn swallow males. We show that within-pair success may increase the...
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The role of ultraviolet light in communication of birds
Šulc, Michal ; Sedláček, Ondřej (advisor) ; Albrecht, Tomáš (referee)
Recently, it has been found that the visual system of birds and humans differ remarkably, especially in the ability to perceive ultraviolet radiation. This component of the spectrum significantly affects various types of the birds' behaviour. UV reflection may be an indicator of the qualities of males, i.e. females often prefer individuals with expressive UV ornamentation. Likewise, parents can distribute the delivered food unevenly among their nestlings, depending on the nestlings' reflection of ultraviolet radiation. Recent studies also showed that the hosts of brood parasites may use UV spectrum as a key for recognizing the parasitic eggs from their own. The aim of my bachelor thesis is to review the current knowledge of the influence of UV radiation on sexual selection of birds, the interaction between parents and offspring and interactions between brood parasites and their hosts.
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Incubation strategies of selected duck species
Klvaňa, Petr ; Albrecht, Tomáš (advisor) ; Šálek, Miroslav (referee) ; Bureš, Stanislav (referee)
- 9 - Incubation strategies of selected duck species Summary of the PhD. thesis Avian incubation is an energetically demanding process. It holds true especially for uniparental incubators in which all incubation efforts are restricted to one individual. All ducks species breeding in northern hemisphere are representatives of birds with uniparental care. High demands of clutch formation and incubation make from ducks perfect model for testing factors influencing parent investment decisions. On the other hand parental investment to actual breeding attempt depends on many factors including breeding season duration, food supply, female's age, risk of predation or resilt of previous nesting attempt. So investigation of this complex problematic is extremely difficult. This thesis is focused on the most important phase of breeding cycle - incubation of clutch. Clutch incubation is associated with high energy cost to maintenance optimal temperature conditions for developing embryos. Morover incubation process can has large effect on female's body mass because of reduction of feeding time. Incubation strategy of success female include many partial tactic reducing predation risk of clutch and incubating female or eggs cooling. The incubation strategies of three ducks species were investigated in this thesis - Mallard...
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Alternative reproductive strategies in Common Pochards (Aythya ferina)
Šťovíček, Ondřej ; Albrecht, Tomáš (advisor) ; Bryja, Josef (referee)
Conspecific brood parasitism (CBP) is one of few alternative reproductive strategies exmployed by females. CBP is common in birds because of their mode of reproduction (ovipary), which allows relatively simple dumping own eggs to foreign nest. This strategy is especially common in birds with precocial young, such as waterfowl. In this study, common pochard (Aythya ferina) was the model organism for study of CBP via molecular methods. It is the very first evidence of this kind of parasitism in non-colonial and non-cavity nesting duck species, based on detection of parasitic eggs via microsatellites markers. A set of 17 microsatellites markers (10 of these were newly found and specific for our species) was optimised for detection of rate of parasitism and relatedness between females in whole population. It was found that CBP is surprisingly high in our species, the parasitic eggs (39 % of 252 eggs) were found in 89% of nests. Despite the fact that females preferentially nest near relatives individuals, parasitic females parasitize equally nests nearby and nests in longer distance. However, no preferential parasitism of related individuals was found. Cost of parasitism seems relatively low for both, host and parasite, in our species. This is in accordance with previous finding that common pochard's...
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Physiology of Carotenoids Metabolism and Ornamental Signalisation in Animals
Gabrielová, Barbora ; Albrecht, Tomáš (advisor) ; Černý, Ondřej (referee)
This theses deal with the use and utilization of carotenoids in secondary ornamentation, particularly in birds. Carotenoids have an important role in animal organisms, and the honesty of carotenoid-based signalization has traditionally been ascribed to anti-oxidant functioning of carotenoids. However, this view has been changed recently showing the potentially harmful effect of carotenoids. The deposition of carotenoids in ornamentation is driven not only by carotenoid intake, but also by physiological processes within the organism. Importantly, when the conditions are suboptimal (and the oxidative stress increases) unstable long aliphatic chains of carotenoids derive into highly reactive non-colorful apo- carotenals. Hence carotenoids may act as classical handicaps, potentially harmful to organism, and this view changes our understanding of honesty of carotenoid-based signalization. The theses focus on summarizing the current knowledge on physiological functions of carotenoids and how they affect secondary coloration, and consist of three chapters. In the first one the basic description of carotenoids is provided, along with an overview of carotenoid classification. The second chapter deals with physiological aspects which affect the carotenoid intake, metabolisation, transport to ornaments, and hypotheses...
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Utilization of a noninvasive genetic methodology for the research on population parameters of waterfowl
Kreisinger, J. ; Albrecht, Tomáš ; Čížková, Dagmar ; Javůrková, V. ; Munclinger, P. ; Stopka, P.
In this contribution a novel method of obtaining genetic material (DNA) from waterfowl nests using non-invasive approach is briefly described and discussed. Pilot project on Mallards (Anas platyrhynchos) showed that the proposed methodological approach can be used to gather data on basic breeding population parameters, including the frequency of renesting, philopatry, or inter-annual dispersion of individuals. Compared with the more traditional approaches of population biology (e.g., direct trapping of birds, individual marking of individuals by rings etc.) the great advantage of the method proposed is its easy application in the field, leading to more effective sampling of entire populations of focal species at large spatial scales. Last but not least, the non-invasive sampling minimizes the disturbance of breeding individuals.
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