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Reproductive Strategies of Geckos: The Role of Macroevolutionary Novelties and Phenotypic Plasticity
Kubička, Lukáš ; Kratochvíl, Lukáš (advisor) ; Rehák, Ivan (referee) ; Boukal, David (referee)
Presented Ph.D. thesis contains an introduction and four chapters concerning reproductive strategies in geckos. The chapters include four peer-reviewed papers and a submitted manuscript. All geckos share rather exceptional reproductive trait known as invariant clutch size, which is characterised by low and invariable clutch size. The first chapter demonstrates that invariant clutch size probably evolved in geckos under selection for enlargement of investment per offspring. On the other hand, in anoles (a group not related to geckos possessing the same mode of reproduction) invariant clutch size allowed considerable decrease of female reproductive burden. Moreover, the interspecific allometries of egg mass and clutch mass in anoles and geckos are informative for understanding of reproductive allometries in a broader context of squamate reptiles. The second chapter is focused on a trade-off in energy investment among reproduction, growth and fat storage in a gecko Paroedura picta. Surprisingly, there seems to exist a clear hierarchical rule for allocation among particular life-history traits. Effect of temperature on reproductive rate in the same species of gecko is the subject of the third chapter. Observed thermal dependence is in contrast to the general relationship suggested under the so-called...
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Effect of prenatal hormonal levels on human sexual orientation
Freudenfeld, Petr ; Havlíček, Jan (advisor) ; Kubička, Lukáš (referee)
Sexual orientation is extensively studied topic nevertheless its etiology remains unclear. Several theories have been proposed to explain it. One of them is Neurohormonal theory of homosexuality. According to this theory, sexual orientation is affected by prenatal levels of androgen hormones. This thesis includes selected studies of experimental manipulations with prenatal levels of hormones in model mammalian species to explain effects of these hormones. Main part of the thesis focuses on the effect of prenatal androgens in humans using somatic biomarkers, for example 2D:4D digit ratio. Studies concerning sex, age and ethnic differences are described in detail. Great attention is dedicated to studies of sexual orientation. In women it seems that sexual orientation could be influenced by prenatal hormones, in men this theory isn't supported. This thesis summarizes and critically evaluates available literature concerning the effects of prenatal hormones on human sexual orientation.
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Parental behavior and recognition of juveniles in geckos of genus Teratoscincus
Suchomelová, Petra ; Frynta, Daniel (advisor) ; Kubička, Lukáš (referee)
4 ANNOTATION The diploma thesis deals with parental behavior and recognition of youngs by two kinds of desert geckos of genus Teratoscincus, specifically T. scincus and T. keyserlingii. The geckos inhabit a very extreme environment where it is not easy to survive, especially for the small hatchlings. Therefore, it is probable that small hatchlings live together with their parents in their territory for some time. If the parents tolerated them inside their territory, they would provide them with an indirect form of parental care. In the first part of the thesis the hypothesis that adults tolerate to the presence of juvenile conspecifics and heterospecifics (Eublepharis macularius) was tested. The main goal was to determine whether adults tolerate juveniles generally or whether they recognize juveniles conspecifics. To support the hypothesis of the adults' tolerance of juveniles the eggs of the adult geckos living in pair were left in their terrarium until the hatching of the juvenile. Further, the reaction of adult geckos to the presence of a E. macularius juvenile (small), admitted into the terrarium, was tested. The aim was to find out whether the two kinds of geckos, preying other geckoes in the nature, show predatory behavior toward the E. macularius. The standard experiment was carried out in the second...
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Self-assessment and mutual-assessment ability in squamate reptiles
Čekal, Jakub ; Frýdlová, Petra (advisor) ; Kubička, Lukáš (referee)
Agonistic interactions throughout the animal kingdom can inflict various costs upon involved animals (decreased fitness, higher risk of predation etc.). To prevent such losses, many species have developed different morphological and behavioural adaptations to display their fighting ability. These adaptations allow animals better assessment of different costs and benefits associated with fighting. Assessment can be divided into two main categories based on the amount of information, that opponents take into account. Self-assessment assumes that rivals consider only their competitive ability and the potential benefits of winning a fight. During mutual-assessment competitors are also capable of considering possible differences in their apabilities and either escalate the fight or back down. My thesis is literary research of this topic in squamate reptiles. The assessment was characterized in several families of Squamata. Additionally, it evaluates the most important traits, that determine a potential winner and introduces different behavioural models of assessment. Used literature suggests that the most reliable predictor of fighting success within these families is the body size, and that mutual-assessment seems to be more prevalent. Keywords: assessment, RHP, aggression, agonistic interactions,...
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Reproductive Strategies of Geckos: The Role of Macroevolutionary Novelties and Phenotypic Plasticity
Kubička, Lukáš
Presented Ph.D. thesis contains an introduction and four chapters concerning reproductive strategies in geckos. The chapters include four peer-reviewed papers and a submitted manuscript. All geckos share rather exceptional reproductive trait known as invariant clutch size, which is characterised by low and invariable clutch size. The first chapter demonstrates that invariant clutch size probably evolved in geckos under selection for enlargement of investment per offspring. On the other hand, in anoles (a group not related to geckos possessing the same mode of reproduction) invariant clutch size allowed considerable decrease of female reproductive burden. Moreover, the interspecific allometries of egg mass and clutch mass in anoles and geckos are informative for understanding of reproductive allometries in a broader context of squamate reptiles. The second chapter is focused on a trade-off in energy investment among reproduction, growth and fat storage in a gecko Paroedura picta. Surprisingly, there seems to exist a clear hierarchical rule for allocation among particular life-history traits. Effect of temperature on reproductive rate in the same species of gecko is the subject of the third chapter. Observed thermal dependence is in contrast to the general relationship suggested under the so-called...
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The effect of steroid hormones on sexually dimorphic bone growth in geckos
Tureček, Adam ; Kubička, Lukáš (advisor) ; Frýdlová, Petra (referee)
The sexual size dimorphism (SSD) is widespread among animals but proximate mechanisms of its ontogeny are still poorly understood even in important groups of vertebrates such as reptiles. Previous experiments in geckos showed that growth of both sexes slows substantially at their older age. Their SSD develops considerably a long time after sexual maturity, it is associated with earlier growth deceleration in the smaller sex and it is controlled by ovarian rather than testicular steroids. The aim of the thesis was to explore the previous knowledge by studying the ontogenesis of the sexually-dimorphic bone growth of the gecko Paroedura picta, the male- larger species with the most explored proximate mechanisms of SSD among geckos. I was most interested in the ontogeny of the growth plates activity and the epiphyseal ossification of the femur in both sexes and their relationship to age, body length, gonadal activity and levels of sex-specific steroids (estradiol and testosterone). The results show that P. picta has determinate growth and that epiphyseal ossification does not contribute to the SSD. The femoral growth plates close at the same age in both sexes; however, their closure occurs at smaller body length in females than in males. In the context of this and the previous studies, estradiol or other...
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Reproductive Strategies of Geckos: The Role of Macroevolutionary Novelties and Phenotypic Plasticity
Kubička, Lukáš
Presented Ph.D. thesis contains an introduction and four chapters concerning reproductive strategies in geckos. The chapters include four peer-reviewed papers and a submitted manuscript. All geckos share rather exceptional reproductive trait known as invariant clutch size, which is characterised by low and invariable clutch size. The first chapter demonstrates that invariant clutch size probably evolved in geckos under selection for enlargement of investment per offspring. On the other hand, in anoles (a group not related to geckos possessing the same mode of reproduction) invariant clutch size allowed considerable decrease of female reproductive burden. Moreover, the interspecific allometries of egg mass and clutch mass in anoles and geckos are informative for understanding of reproductive allometries in a broader context of squamate reptiles. The second chapter is focused on a trade-off in energy investment among reproduction, growth and fat storage in a gecko Paroedura picta. Surprisingly, there seems to exist a clear hierarchical rule for allocation among particular life-history traits. Effect of temperature on reproductive rate in the same species of gecko is the subject of the third chapter. Observed thermal dependence is in contrast to the general relationship suggested under the so-called...
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The utilization of "doubly labelled water" method in studies of avian ecology
Míčková, Kristýna ; Albrecht, Tomáš (advisor) ; Kubička, Lukáš (referee)
Doubly labelled water method is used to estimate CO2 production and energy expenditure. The method is based on the application of water containing rare hydrogen and oxygen isotopes, and estimation of the difference in elimination of these isotopes from the body (used as an indirect estimate of CO2 production), which is measured mostly from two blood samples taken over a defined time interval (usually 24 hours). Here I summarize the assumptions and methodological approaches associated with the use of the doubly labelled water method in bird studies. Studies on birds typically evaluate energy expenditure associated with prasitic infections and immune response, ageing, investments into the reproduction, flight and migration, ornamentation. In comparison with other methods doubly labelled water is appropriate for measurement of energy expenditure associated with various aspects of biology in targeted individuals. Key words: Doubly labelled water, energy expenditure, metabolism, birds, reproductive investments, flight costs
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Food preferences and foraging mode in lizards (Squamata: Sauria)
Křivánek, Jan ; Gregorovičová, Martina (advisor) ; Kubička, Lukáš (referee)
In terms of food-foraging, lizards usually occupy one of two possible strategies ("foraging mode"). The first one is called "sit and wait" and it is defined by waiting on one position for a long time with a minimum movements and attack is based on visual cues on prey which gets to a certain distance. The second one is the "active foraging" in which the predator moves through terrain and it detects with help of chemical cues by nasal olfactoric system or vomeronasal system, with which is able to find a prey. Sometimes the third mode is also presented as a transition - "saltatory foraging" or a continuum between two these extreme strategies. Specific variables, which reflects the activity of a predator, are used to determine the "foraging mode" - MPM, PTM, PAM and AD. Within these predators a whole set of sensory adaptations ( such as enlarged olfactory lobes, a large abundance of taste buds, two fovea centralis in macula), morphological adaptations (e.g.shortening of the jaw, slender body morphology, forked tongue) and food adaptations (yellow color preference, ontogenetic shift to herbivory) are presented. Powered by TCPDF (www.tcpdf.org)
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