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Behaviour and ecology of leopard geckos (Eublepharis macularius)
Jančúchová Lásková, Jitka ; Landová, Eva (advisor) ; Moravec, Jiří (referee) ; Sedláček, František (referee)
During evolution, the natural selection favours individuals with the best survival strategy and the highest reproductive success. From the evolutionary point of view, hybridization plays an important role in the process of speciation. Avoiding predators by choosing the most appropriate antipredator strategy increases the animal's chances of survival as well. Studying fitness consequences of hybridization and predation in Eublepharis macularius (Eublepharidae) was the main objective of this theses. Compared to other vertebrate groups, the reliable records on hybridization and its effect on the hybrid's fitness (fertility, survival) in lizards are scarce, despite their ability to hybridize between genetically distant species. These effects were examined in two species of eyelid geckos (E. macularius and E. angramainyu). We aimed to discover whether they were willing to hybridize with a heterospecific species and how the fitness of the hybrids would be affected. Similarly, were studied more genetically related forms of E. macularius species complex, the potential precopulatory barriers, and fitness cost of this hybridization. Analysis of published data has shown that the lizards hybridize between very phylogenetically distant species and are even "more successful" than birds or turtles. Surprisingly,...
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Spontaneous preference for colors in humans and non-human primates: Comparative study
Skalníková, Petra ; Nekovářová, Tereza (advisor) ; Sedláček, František (referee)
Colors and color-perception may play an important role in animal ethology (foraging, intra or inter-species communication). However, trichromatic color vision is quite rare among mammals and occurs only in some primate species. Humans, apes, and most of the Old World primates are trichromats, whereas color vision among New World primate species varies strikingly. The pigment gene perciving longer wavelenghts (red) have appeared most recently. Moreover, the pigment genes for the perception of red color have appear independently in these two primates lines (Old and New World) (Kainz et al, 1998). Although the genetic mechanism of trichromacy is quite understood, the question remains, what was the adaptive advantage responsible for the spreading of the above mentioned genes. The basic functions of trichromatic vision may be better detection of food (folivory and frugivory hypothesis), signaling or warning functions. The main goals of the thesis is to study spontaneous preference for color in children (pre- school and school age) and non-human Old World primates who have routine trichromic vision. Moreover, the thesis will focus on preference of red color to understand what was an adaptive function of red color perception. We assume that the spontaneous preference for color may reflect an adaptive...
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Optimization of delivery date in cervids
Schnebergerová, Adriana ; Dušek, Adam (advisor) ; Sedláček, František (referee)
Female mammals adjust their birth date according to actual environmental conditions and their own condition to maximize their reproductive fitness. Optimizing of birth date allows the mothers to maximize not only their own fitness but also the fitness of their offspring. The aim of my bachelor`s thesis is to document the optimization of the delivery date in the deer family (Cervidae), i.e. timing of delivery whereby females can attain successful reproduction. This family is thanks to world-wide areal an ideal taxon for the study of optimization of the delivery date. 40 species and 200 subspecies renders this family one of the most diversified and the most numerous of even-toed ungulates (Artiodactyla). In general, factors that affect the timing of the delivery date are: ecological, behavioral, reproductive, physiological and genetic. These factors include, for example, seasonality, availability and quality of food, condition, social rank and age of the female, the presence of the male and the sex of the offspring. Depending on actual environmental conditions, female deer may either hasten or, on the contrary, delay the delivery date and thus maximize the chances of survival of their offspring. The synchronization of the birth date is another important strategy which allows females to reduce the...
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Factors influencing variability i behaviour towards novel and aposematic prey in tits (Paridae)
Adamová, Dana ; Exnerová, Alice (advisor) ; Sedláček, František (referee) ; Šálek, Miroslav (referee)
Inter-specific and intra-specific variation in reactions towards novel and aposematic prey was found in several species of tits (Paridae). This Ph.D. thesis is focusing on various factors influencing reactions towards novel and aposematic prey in three European species of tits. We tested differences in exploration behaviour, neophobia, dietary conservatism, personality, age and experience as well as ability of avoidance learning and generalisation. We found no difference in exploration behaviour and in reaction towards novel prey in two different populations of great tits (Parus major). But the birds from the Finnish population were more neophobic than Czech birds, but they attacked aposematic firebug (Pyrrhocoris apterus) more often and faster than Czech birds. The difference can be explained by a different experience with local aposematic prey communities. Than we studied initial wariness in naive juveniles of great tits (P. major), coal tits (Periparus ater) and blue tits (Cyanistes caeruleus), and we tested how the initial wariness towards novel and aposematic prey can be deactivated by experience with palatable prey. Great tits and coal tits from experienced groups significantly decreased their neophobia towards both types of prey while blue tits did not change their strongly neophobic...
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Body size as an implicit factor: case studies of life-history strategies and behaviour
Šimková, Olga ; Frynta, Daniel (advisor) ; Sedláček, František (referee) ; Rehák, Ivan (referee)
Body size has a potential to influence almost any trait in animal biology. The thesis contains four case studies (I - IV) covering four various situations and four various taxa, mainly squamate reptiles (Lepidosauria). Body size is a connecting factor for all these studies, in which I and my co-authors tried to elucidate various implications of body size. I. The sex ratio in Cuban boa (Chilabothrus angulifer) litters is often male or female biased. The neonates are so large, that are able to accept the same type of prey as are adults (in contrast to the other Chilabothrus species). We found that both the sexes are of the same size and shape at birth. Large size of the neonates a long lifespan lead to considerable generation overlaps. This could clarify our findings that small females produce sons whereas the larger ones deliver daughters. Males are smaller than females, probably also less philopatric and refuse food during breeding season. We can conclude that females manipulate the sex ratio of neonates according to its own body size, in order to decrease the probability of competition with their own offspring. II. Mangrove-dwelling monitor lizard (Varanus indicus) shows one of the greatest degrees of sexual size dimorphism among monitor lizards. We recorded the growth of the individuals from...
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Levels of physiologically active substances during the ontogeny of social hierarchy in two house mouse subspecies
Bufková Daniszová, Kristina ; Stopka, Pavel (advisor) ; Dušek, Adam (referee) ; Sedláček, František (referee)
2 Abstract Social interactions of animals are represented by a complex network of relations among individuals affected by many factors. From a practical point of view, it is very complicated or even impossible to observe these interactions under natural conditions and consider all fundamental underlying factors. A suitable solution may be, for example, to use a social environment of so called fraternal pairs. With a simplified model represented by pairs of brothers it is possible - given a properly set length of the experiment and age of the individuals involved in it - to reveal various aspects of establishing social hierarchies. A key factor influencing an individual's position (especially of a male) in the group is considered to be his physical fitness which is usually connected with his size and hence with his body mass. In addition to physical qualities of individuals, a fundamental role for achieving the "social" success is also played by the ability to communicate these qualities (e.g. through chemical signals) to other members of the social group. Apart from somatic and communication characteristics determining chances of an individual to succeed in the social competition, the internal regulation of these aspects presents another interesting subject for studies. In this respect a special attention...
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Contribution of social dominance on performance in spatial cognitive tasks in pigeons
Janská, Iveta ; Landová, Eva (advisor) ; Sedláček, František (referee)
Diploma thesis generally compares individual success pigeons in spatial tasks of varying complexity (in a role that requires abstraction of visual stimuli representing spatial relationships on the touch screen using two different strategies and spatial search task the middle plate of a series of plates with different variants of location) with hierarchical status of males and group females. Specifically thesis compares individual success pigeons in spatial tasks of varying complexity. The hardest task requires a certain level of abstraction of visual stimuli representing spatial relationships using experimentally induced two strategies: mapping strategy or specific symbol association with a position in space. The role tests on the touch screen with the help of operant conditionings. Difficulty in various stages of growing, the last stage role does manage only some individuals. Conversely easier task in real space with a bird tasked with finding the midpoint between objects in different variants locations within the arena. The difficulty of the task is not growing, and it can solve some individuals who have not learned operant conditioning if the previous job. Performance in cognitive tasks could be affected by the hierarchical status of the animal in the group. Pigeons position in the hierarchy has...
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Repeatability and personality in tests of exploratory behaviour
Žampachová, Barbora ; Frynta, Daniel (advisor) ; Sedláček, František (referee)
Personality, or behavioural differences among individuals, which are stable both in time and across contexts, is a highly popular topic. Currently there has been an increase of interest in the relationship between personality and repeatability, which is a methodical approach developed to measure the stability of interindividual differences in time. The aim of this thesis is to evaluate the personality of rats according to behavioural patterns exhibited under widely used testing procedures in new environment (open field test, hole board test) and to compare, how behavioural traits in these tests mutually correlate and change over time. Each test trial was repeated eight times with different intervals (24 hours, 6 days, 4 weeks). The results suggest that most of the recorded behavioural variability can be explained with three principal axes. The first one is associated with loco-exploratory activity of the subject. The elements of behaviour associated with this axis are the most repeatable. The second axis is mostly associated with time the animal spent in the central part of the arena and the third axis represents the interest in holes in hole board test. These two axes are less repeatable. A significant effect of the identity of the animal was found in all behavioural traits, associated with these...
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