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Hormonal control of male sexual behaviour in reptiles
Schořálková, Tereza ; Kratochvíl, Lukáš (advisor) ; Landová, Eva (referee)
The most important hormone affecting typical male sexual behavior in reptiles is testosterone, but also other steroid hormones such as dihydrotestosterone, estrogens or progestins may be involved in this regulation. According to the organizational-activational hypothesis testosterone acting during early ontogenic stage has an organizational effect on adult behavior and this behavior is triggered by influence of recent levels of hormones. Moreover, it was formulated the hypothesis on temporary organization of male sexual behvior that could change existing interpretations. Reptile reproductive strategies use to be classified according to gametogenesis and steroidogenesis as associated or dissociated reproductive strategies howerever, this division is rather artificial. This review summarizes existing knowledge of the hormonal influence of sexual behavior in reptiles, and comments the most common methods.
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The effects of mating with multiple males on reproductive success of a female: An experimental study in leopard gecko (Eublepharis macularius)
Ševčíková, Pavlína ; Frynta, Daniel (advisor) ; Rehák, Ivan (referee)
The aim of the project was to test female advantages of promiscuous and/or polyandrous mating. Although, previous studies reported improved reproductive success of females copulating with multiple males in many model species, including Eublepharis macularius, this study failed to demonstrate such a benefit of polyandry. Traits reflecting female reproductive success, i.e. the number of produced eggs, egg mass, hatchability, hatchling mass, growth and survival were not influenced by copulation with multiple partners, but some of them were dependent on female condition. Only initial stages of juvenile growth were influenced by female identity and/or investment.
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Hormonal control of male traits in leopard gecko, Eublepharis macularius
Schořálková, Tereza ; Kratochvíl, Lukáš (advisor) ; Rehák, Ivan (referee)
It is generally believed that the presence of male traits is regulated by androgens. This thesis is designed to reveal the influence of testosterone on male traits in the leopard gecko, Eublepharis macularius. The noninvasive skin application mixture of vegetable oil and testosterone was used to manipulate the hormonal status of females and castrated males. This method has proven to be an effective alternative to the widely used hormonal implants. Manipulation was successfully validated, and there was apparent progressive increase of male sexual behavior in both groups. In females, the onset lasted much longer time, but both groups were able to perform all components of males sexual behaviour. Furthermore, I found that, contrary to widespread view, male sexual behavior persisted several weeks after reduction of testosterone levels in both manipulated groups. These results bring new evidence for temporary organization of male sexual behaviour by testosterone. Powered by TCPDF (www.tcpdf.org)
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Testing of spatial orientation in leopard gecko ( Eublepharis macularius)
Voňavková, Monika ; Landová, Eva (advisor) ; Svoboda, Jan (referee)
The ability of the spatial orientation of the reptiles is not fully researched yet. It is unknown if reptiles use only simple types of navigation, for example cue learning (one key mark), or more difficult types, for example allothetic navigation (combination of marks) or cognitive map (mental representation of the area). The main aim of this thesis was examine the possibility of the spatial orientation in lizard leopard gecko (Eublepharis macularius) in modificated Morris water maze (MWM). Design of the experiments was based on Parallel Map Theory, a theory which describes using spatial information from more navigation frames. The leopard gecko preferences of orientation frames were tested . That means the ability to combinate the spatial information from the bearing maps (one mark and gradient) and the sketch maps (local marks). This ability is prerequisite for creating the integrated map. The research was also focused on the significance of the simple cue learning strategy and cognitive more difficult allothetic navigation for the orientation of leopard gecko. Leopard geckos can use the combination of information from the navigation frames, which indicate the possibility of integrated map creation. Usage of navigation strategies is individual. Keywords: reptiles, leopard gecko, spatial...
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Hormonal control of male traits in leopard gecko, Eublepharis macularius
Schořálková, Tereza ; Kratochvíl, Lukáš (advisor) ; Rehák, Ivan (referee)
It is generally believed that the presence of male traits is regulated by androgens. This thesis is designed to reveal the influence of testosterone on male traits in the leopard gecko, Eublepharis macularius. The noninvasive skin application mixture of vegetable oil and testosterone was used to manipulate the hormonal status of females and castrated males. This method has proven to be an effective alternative to the widely used hormonal implants. Manipulation was successfully validated, and there was apparent progressive increase of male sexual behavior in both groups. In females, the onset lasted much longer time, but both groups were able to perform all components of males sexual behaviour. Furthermore, I found that, contrary to widespread view, male sexual behavior persisted several weeks after reduction of testosterone levels in both manipulated groups. These results bring new evidence for temporary organization of male sexual behaviour by testosterone. Powered by TCPDF (www.tcpdf.org)
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Hormonal control of male sexual behaviour in reptiles
Schořálková, Tereza ; Kratochvíl, Lukáš (advisor) ; Landová, Eva (referee)
The most important hormone affecting typical male sexual behavior in reptiles is testosterone, but also other steroid hormones such as dihydrotestosterone, estrogens or progestins may be involved in this regulation. According to the organizational-activational hypothesis testosterone acting during early ontogenic stage has an organizational effect on adult behavior and this behavior is triggered by influence of recent levels of hormones. Moreover, it was formulated the hypothesis on temporary organization of male sexual behvior that could change existing interpretations. Reptile reproductive strategies use to be classified according to gametogenesis and steroidogenesis as associated or dissociated reproductive strategies howerever, this division is rather artificial. This review summarizes existing knowledge of the hormonal influence of sexual behavior in reptiles, and comments the most common methods.
|
|
|
The effects of mating with multiple males on reproductive success of a female: An experimental study in leopard gecko (Eublepharis macularius)
Ševčíková, Pavlína ; Frynta, Daniel (advisor) ; Rehák, Ivan (referee)
The aim of the project was to test female advantages of promiscuous and/or polyandrous mating. Although, previous studies reported improved reproductive success of females copulating with multiple males in many model species, including Eublepharis macularius, this study failed to demonstrate such a benefit of polyandry. Traits reflecting female reproductive success, i.e. the number of produced eggs, egg mass, hatchability, hatchling mass, growth and survival were not influenced by copulation with multiple partners, but some of them were dependent on female condition. Only initial stages of juvenile growth were influenced by female identity and/or investment.
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