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Chemical communication in field mice of the genus ApodemusApodemus
Obstová, Lucie ; Stopka, Pavel (advisor) ; Vohralík, Vladimír (referee)
The bachelor thesis deals with a special sebaceous organ that probably serves as a chemical communication means with four species of Apodemus field mouse - A. flavicollis, A. sylvaticus, A. agrarius and A. microps. This organ is found on the ventral side of a tail, so it is classified as a caudal organ. It consists of significantly enlarged sebaceous glands. It is particularly developed mainly with males; however, both females and infants have it as well. Its morphological structure has the same base regardless of the species, gender, and/or age; however the extent of development varies among species. The organ releases a secretion whose chemical content is unknown so far. Thanks to the gas-liquid chromatography, researchers have found out that there are both variations in the secretion contents among individual species, as well as within the same species. This kind of secretion is basically a characteristic feature of an individual, as it bears information about the species, gender, age and even the population affiliation. Functions of the organ stay unknown as well. It might serve to mark the territory, to play a role in social interactions (i.e. agonistic behaviour) and/or to be an important part of copulatory behaviour.
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Acoustic communication and its variability in selected populations of ground squirrels of the genus Spermophilus
Schneiderová, Irena ; Vohralík, Vladimír (advisor) ; Sedláček, František (referee) ; Špinka, Marek (referee)
The thesis deals with vocalizations produced by Eurasian ground squirrels of the genus Spermophilus. It is mainly focused on inter-species and intra-species variability in acoustic structure of alarm calls which are emitted in presence of predators.The major part of the thesis deals with intra-species variability in acoustic structure of the alarm calls in five Eurasian ground squirrels, Spermophilus citellus, S. taurensis, S. xanthoprymnus, S. suslicus and S. fulvus. It has been confirmed that the alarm calls of these ground squirrels show a high level of species specificity. The thesis further describes another vocalizations produced by three Eurasian ground squirrel species, Spermophilus suslicus, S. citellus and S. fulvus, and shows that with the exception of the alarm calls, vocal repertoires of these three ground squirrels are remarkably similar. The last part of the thesis deals with individual distinctiveness of the alarm calls of three Eurasian ground squirrels, Spermophilus citellus, S. taurensis and S. xanthoprymnus. It has been shown that the alarm calls of these species have a significant potential to encode information about caller identity.
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Feeding ecology of the Stone marten (Martes foina) in Europe.
Nováková, Lucie ; Vohralík, Vladimír (advisor) ; Fuchs, Roman (referee)
During last decades, the stone marten, Martes foina (Erxleben, 1777) became a synanthropic animal and its population is increasing. This review is summarizing the knowledge about its feeding habits throughout Europe. In the first part the methods are introduced which are used for study of feeding ecology, for example scat analysis or the analysis of stomach and gut content. The way of calculations of some characteristic values most frequently used in study of feeding ecology of marten are described. In the second part the geographic variability and the seasonal changes in the marten's food in the different parts of Europe are analyzed. It seems that the type of habitat, in which the stone marten lives, affects its feeding habits. The differences its feeding in the urban and rural habitats are shown. There are intrahabitat differences too. In the third part of this work the main components of marten's food are described which include various small vertebrates, invertebrates (mostly insects) and fruit, and some marten's food specifics are discussed. Food resources provided by man are mentioned. Key words: feeding ecology, stone marten, Mustelidae
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Vigilance and escape behaviour in ground squirrels (tribe Marmotini)
Milerová, Petra ; Vohralík, Vladimír (advisor) ; Matějů, Jan (referee)
In the ground squirrels, vigilant antipredator behaviour is frequently studied as a part of antipredator strategy. More vigilant animals have greater chances to avoid a predator attack. But it's also true, that animals allocating more time to vigilance, can allocate less time to foraging. There is obvious trade-off between vigilance and foraging. Ground squirrels, marmots and prairie dogs have to receive a lot of food to accumulate fat reserves for the hibernation period, and in case of juveniles also to ensure their growth. Therefore, they are forced to allocate time between aforementioned activities suitably. In view of the close relationship between vigilance and foraging, these two activities are often investigated together. The most important factors influencing aforementioned activities are number of simultaneously active individuals and presence of visual barriers. An affect has also age, sex and reproductive status of the individual or caloric content of the food. After the detection of a predator with the aid of vigilance, can be initiated escape response. Escape distance, escape velocity and escape behaviour in general are influenced especially by the type of predator, type of vegetation cover and individual distance from a burrow entrance. It is important that total energy costs of these...
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Genetic variability in the European ground squirrel (Spermophilus citellus) in Czech Republic
Starcová, Magda ; Vohralík, Vladimír (advisor) ; Kotlík, Petr (referee)
The European ground squirrel (Spermophilus citellus) (hereinafter EGS) is under the Law on Nature Protection and is included as a critically endangered into the Red List of Endangered Species. In the Czech Republic, which represents the northwestern border of the species range, EGS currently occurs on 34 localities, which are relatively small and isolated from each other. The spread of this species to central Europe was connected with neolithic deforestation. Disjunctive type of distribution of EGS was caused by strong decline of its abundance during the second half of the 20th century due to changes in field management, fragmentation of landscape and other factors. It can be expected that this process left traces on the genetic structure of EGS populations. The major objective of this study was a detailed analysis of genetic variability of EGS populations in the Czech Republic and searching for corelations with available data about its biology and demography. It was used 13 microsatellite loci and in total were processed 408 samples from 27 localities in CZ and 3 samples from one Hungarian locality as an outgroup. With aid of various methods, details of substructure and diferentiation of individual populations, genetic variability, degree of inbreeding and geographic distribution of genetic variability...
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Acoustic communication in two species of ground squirrels Spermophilus citellus and S. taurensis (Sciuridae; Rodentia).
Schneiderová, Irena ; Petrusková, Tereza (referee) ; Vohralík, Vladimír (advisor)
6 ABSTRACT Since now, acoustic communication and alarm calls of European ground squirrel and the recently described S. taurensis have been poorly studied. Aim of this study is to make first steps in studying and understanding their acoustic communication and alarm calls. It was found, that the European ground squirrel produces 6 vocal (growl, rapid growl, scream, squeak, chirp, whistle) and 1 nonvocal (tooth chatter) sounds. These sounds are produced when sousliks are directly threatened by predator or during their social contacts. The alarm call of European ground squirrel as well as of S. taurensis is the whistle. It usually consists of two different elements, which can be fused, overlapped in time or separated by short interval. The first element has a constant frequency, while the second one has little frequency modulation. In some cases, one of these elements can be missing. The study reveals individual variation in the alarm calls in both species. Sexual differences in alarm calls of S. taurensis were found. Keywords: Spermophilus citellus, Spermophilus taurensis, Sciuridae, ground squirrel, antipredator behaviour, acoustic communication, vocalization, vocal repertoire, alarm call.
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