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Body mass changes during breeding in birds
Drekslerová, Šárka ; Hořák, David (advisor) ; Klvaňa, Petr (referee)
Body mass is one of the criteria estimating individual's body condition and predicates an ability to cope with environmental conditions. To maintain the body condition the individual needs energy supply. In my essay I am concerned with life-history strategies of birds through the adjustment with increased energy demands during incubation period and with changes in body mass relating with these strategies. The individual can cover energy requirements directly from food ("income breeder") or make an energy storage in advance and draw the energy later during breeding ("capital breeder"). According to the type of breeding environment, access of strategy evolves and how changes its body mass in consequence of the elected strategy. Income breeding occur in small birds in good predictable environment with high food abundance and it is characterized by varying body mass changes. In contrast, capital breeding occur in hardly predictable environments or in cold areas with low food abu ndance and it is characterized by linear mass loss. Body mass has a great influence on breeding success. Female make a decision to breed or not based on her body condition. Breeding with female bad body conditon incerases a risk of abandoning the nest and nest failure. Another important factors are e.g. the weather, age of breeding...
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Optimalization of artificial incubation of eggs and embryos in northern pike (\kur{Esox lucius L.}) under controlled conditions
HAMPL, Jan
Within my diploma thesis I have been trying to resolve the possibilities of optimization of artificial incubation of eggs and embryos in northern pike (Esox Lucius L.) under controlled conditions during three different experiments. In the first experiment was investigated the effect of three different semination solutions to the success of incubation of eggs and embryos in northern pike. I watched the survival of eggs and embryos, larvae hatching abnormalities and biometrics of larvae. It was found that the best overall results were achieved with semination solution composed of 15 ml of chemical crystalic urea per 1 liter of water, with an appropriate amount of abnormalities and highest larvae survival. In the second experiment were performed manipulation with developing eggs at given time intervals after fertilization of eggs. I watched the survival of eggs and embryos, abnormality and biometrics of hatched larvae. It was found that the lowest survival, abnormalities, and smallest TL and W were reached during manipulations within 24 hours after fertilization. In the third experiment was investigated the effect of water temperature on the length of the incubation of eggs and embryos in northern pike. With regard to the overall survival, larvae hatching, abnormalities and size of larvae achieved the best results temperatures 6 and 10 ° C. Conversely, it is entirely unsuitable for incubation temperature of 3 ° C (lowest survival, large amounts deformities). Different incubation temperatures have also confirmed the effect of water temperature on biometrics of hatched larvae.
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Effect of water temperature on early life history in African catfish (Clarias gariepinus)
PROKEŠOVÁ, Markéta
In the present M. Sc. thesis the effect of water temperature (thermal range: 17.4 - 38.6 °C) on early life history (during interval from egg fertilization to full yolk sac depletion by 50 % of larvae; Fe - Re50) in African catfish (Clarias gariepinus) was examined. Length of the incubation period (i. e. interval from egg fertilization to the moment of hatching of 50 % of individuals; Fe - H50), length of the hatching period (i. e. interval from hatching of 5 % of individuals to hatching of 95 % of individuals; H5 - H95), length of the period up to the first intake of exogenous food (i. e. interval from H50 to the first intake of exogenous food by 50 % of individuals; H50 - S50) and length of the period up to the full yolk sac resorption (H50 - Re50) were inversely proportional to the incubation temperature. Period of the yolk sac resorption was significantly prolonged (approximately six times) because of using of exogenous food (compared to treatments without added external food supplies). Embryonic development was theoretically stopped at temperature 15.4 °C and hatching occured after c. 12 effective day-degrees. Size of larvae increased during embryonic and larval period. Size of larvae at H50, S50 and Re50, was inversely proportional dependent on the incubation temperature. Size of individuals at Re50 was increased (approximately twice) because of using of exogenous food (compared to treatments without added external food supplies). Yolk sac volume (YsV) decreased during embryonic and larval period. YsV at H50 was correlated with size of egg and YsV was S50 was inversely proportional to the incubation temperature. A dry weight of yolk sac at H50 represented c. 89 % of total dry weight of hatched larvae. During the period of endogenous feeding c. 75 % of dry weight of egg was converted into the larval somatic tissues. Efficiency of energy conversion during the period of endogenous feeding is lower (60 %). The energetical value of total dry matter and content of sulfur in dry matter was decreasing during the period of endogenous feeding (in order: egg, hatched larvae, larvae at Re50). Content of nitrogen and carbon in dry matter was increasing during the embryonic period and afterwards was decreasing during the larval period. In term of survival, the zone of thermal tolerance for early life history in African catfish ranges from 19 to 33 °C (with thermal optimum between 23 and 30 °C), i. e. this fish belongs to the typical thermophilous species. The suboptimal temperatures lies within intervals 21 - 23 °C and 30 - 33 °C, respectively. Temperatures below 17.5 °C as well above 35.5 °C can be considered as the lethal temperatures already during embryonic period and those below 19 °C and above 33 °C as the lethal ones during larval period, respectively. In term of bioenergy, the thermal optimum for early life history in African catfish lies between 23 - 28 °C.
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The photoperiodicity effect on the selected phasmid species egg growth
TOCHOROVÁ, Pavla
The object of the thesis is to discover the importance of photoperiodicity in the Ramulus artemis and Peruphasma schultei growing process. These species differ in the area of presence, anti-predator behavior and the reproduction method. Their eggs were incubated at a constant temperature divided into four photoperiods. Incubation time, hatching success and the daytime of hatching were precisely documented. The photoperiodicity effect on both selected species has been evidenced by statistical data evaluation. The theoretical part deals with a general description of the reference order of phasmatodea (Phasmatodea) focusing on its reproduction and growth. Then appoints the climatic factors influencing the physiological processes in the insect body.
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