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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...

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...

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...

6 ABSTRACT Conditional ornaments plays irreplaceable role in sexual selection in non-small part of by sexual reproduction reproducing animals. Fastidiousness of generating and later also carrying of these ornaments which show condition of their wearer, burdens also metabolism in non-small scale. This thesis tests hypothesis of mutual addiction between conditional ornaments, as the indicators of qualities of individuals and metabolism, as the most significant source of free radicals which are responsible for oxidative stress. The real weight of influence of ornament fastidiousness on organism, resp. on redox state, is tested in this thesis. Manipulations which were performed with individual males of model species should point how much the selected factors correlate each other. The barn swallow (Hirundo rustica) is the model species. Analyses of dates collected during trapping which were realized in breeding seasons in 2012 and 2013 does not show any important trends between observing variables. This fact is confirmed by minimal differences and inconsistent variability of levels of measured antioxidants - oxidoreductases, superoxide dismutase and glutathione peroxidase. The marginal effect of manipulations with one of the conditional ornaments which are presented in model species supports the hypothesis of...

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...