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The association between tail streamer length and male atractiveness in barn swallows
Záleská, Josefína ; Albrecht, Tomáš (advisor) ; Cepák, Jaroslav (referee)
In the view of the sexual selection research, the barn swallow (Hirundo rustica), and its European subspecies (Hirundo rustica rustica) in particular, belongs to the most detailed studied bird species all over. The males of the European subspecies have in general markedly longer outer tail streamers than the females have and, based on research in several European populations, this tail ornamental trait plays an important role in sexual selection in this subspecies. The length of the tail streamers was found to be related to several main parameters that are connected to individual attractiveness in socially monogamous pairing systems, such as early partner acquisition and earlier nesting initiation date, the probability of repeated nestings in a breeding season or the number of successfully raised young. The main aim of the presented diploma theses is to assess to what extend is the length of the tail streamers a determinative trait related to male attractiveness in a South Bohemian population of the European barn swallow. The results of this thesis imply that the tail streamer length of males is, indeed, an attractive trait in this population, connected to multiple mating advantages. KEY WORDS Sexual dimorphism, sexual selection, barn swallow, nesting initiation, attractivity, reproductive success,...
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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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