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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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Fitness costs and benefits of sexual promiscuity in birds
Zdobinská, Helena ; Michálková, Romana (advisor) ; Sládeček, Martin (referee)
In more than 75 % bird species, extra-pair paternity (situation, when at least one extra-pair young in the nest is sired by other male than a social partner of female) has been found. While male interset in attending extra-apir copulations (EPC) seems to be intuitive (more offsring sired), female motivation to engage in EPC are much less clear and obvious. Therefore, many adaptive hypotheses have been proposed to explain female proscuity. Adaptive hypothese state, that female benefits from this behaviour (higher genetic quality of offspring). The empirical evidence for such benefits, however, are missing and adaptive hypotheses remain a controversial topic. This has led to the emergence of non-adaptive hypothesis, that assume that EPC can evolve as a by-product of selection on other trait and female may not benefit from this behaviour. However, non-adaptive hypotheses are often neglected. Aim of this bachelor thesis is to take into account benefits and costs for both sexes and to point out some of the limitations of studies on EPC. Key words: Extra-pair paternity, extra-pair copulations, promiscuity, adaptive hypothesis, nonadaptive hypothesis, sexual selection, limitation of studies
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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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Fitness costs and benefits of sexual promiscuity in birds
Zdobinská, Helena ; Michálková, Romana (advisor) ; Sládeček, Martin (referee)
In more than 75 % bird species, extra-pair paternity (situation, when at least one extra-pair young in the nest is sired by other male than a social partner of female) has been found. While male interset in attending extra-apir copulations (EPC) seems to be intuitive (more offsring sired), female motivation to engage in EPC are much less clear and obvious. Therefore, many adaptive hypotheses have been proposed to explain female proscuity. Adaptive hypothese state, that female benefits from this behaviour (higher genetic quality of offspring). The empirical evidence for such benefits, however, are missing and adaptive hypotheses remain a controversial topic. This has led to the emergence of non-adaptive hypothesis, that assume that EPC can evolve as a by-product of selection on other trait and female may not benefit from this behaviour. However, non-adaptive hypotheses are often neglected. Aim of this bachelor thesis is to take into account benefits and costs for both sexes and to point out some of the limitations of studies on EPC. Key words: Extra-pair paternity, extra-pair copulations, promiscuity, adaptive hypothesis, nonadaptive hypothesis, sexual selection, limitation of studies
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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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