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Incubation effort in Common Pochard and its determinants
Drekslerová, Šárka ; Hořák, David (advisor) ; Musil, Petr (referee)
Incubation of avian eggs is an energy demanding process. Incubating parent faces a conflict between investment into optimal thermal conditions for developig embryos and meeting of own energy requirements. This applies especially in uniparental incubators such as ducks. During incubation, female utilizes energy from fat storage or actual food intake. The proportion of energy used from food than may reflect the time spent by female on the nest. The utilizing of these both sources ratio plays a role in time spent on nest. The aim of the thesis was to describe an incubation rhythm in females of Common Pochard (Aythya ferina) and relate them to climatic variables and changes in body mass. Data were collecetd for three years in the Poodříí Landscape Protected Area at free-living females. We placed a weighting mechanism under the nest with conected datalogger recording voltage variations, which offered me an information about female body mass and time and duration of recesses. Incubation rhytm of females was described by time spent on time ("incubation constancy"), recess frequency and recess duration. Females left the nest most grequently at night-time and during dawn and dusk. Probable explanation of this pattern is better food availability in the night-time and lower risk of nest predation by predators...
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Influence of external conditions on egg incubation in lapwings (genus Vanellus) in temperate and subtropical climate
Pešková, Lucie ; Šálek, Miroslav (advisor) ; Hořák, David (referee)
During incubation, most birds require the presence of at least one parent to ensure suitable incubation conditions for embryo development. The main factors that affect the development of the embryo are temperature, humidity and egg turning. In this work, incubation conditions were investigated in two biparental Lapwing species (genus Vanellus), the Northern Lapwing (Vanellus vanellus), which faces the risk of egg cooling in temperate areas, and the Red-wattled Lapwing (Vanellus indicus), which faces the risk of egg overheating in the subtropics. A laboratory experiment testing the thermal properties of the Red-wattled Lapwing nest lining showed that it selects lining material that slows down temperature growth during egg heating, thus ensuring suitable thermal conditions during parental absence at high ambient temperatures. Temperature and egg turning during incubation were recorded by an artificial egg with a built-in sensors placed in the nests of both target species; data collected by the sensors were stored by a base-station located nearby. The average egg temperature was 32.5 řC for the Northern Lapwing, and 35.0 řC for the Red-wattled Lapwing. Egg temperature in both species fluctuated significantly, affected by many factors. Egg temperature increased with increasing ambient temperature, it...
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Influence of external conditions on egg incubation in lapwings (genus Vanellus) in temperate and subtropical climate
Pešková, Lucie ; Šálek, Miroslav (advisor) ; Hořák, David (referee)
During incubation, most birds require the presence of at least one parent to ensure suitable incubation conditions for embryo development. The main factors that affect the development of the embryo are temperature, humidity and egg turning. In this work, incubation conditions were investigated in two biparental Lapwing species (genus Vanellus), the Northern Lapwing (Vanellus vanellus), which faces the risk of egg cooling in temperate areas, and the Red-wattled Lapwing (Vanellus indicus), which faces the risk of egg overheating in the subtropics. A laboratory experiment testing the thermal properties of the Red-wattled Lapwing nest lining showed that it selects lining material that slows down temperature growth during egg heating, thus ensuring suitable thermal conditions during parental absence at high ambient temperatures. Temperature and egg turning during incubation were recorded by an artificial egg with a built-in sensors placed in the nests of both target species; data collected by the sensors were stored by a base-station located nearby. The average egg temperature was 32.5 řC for the Northern Lapwing, and 35.0 řC for the Red-wattled Lapwing. Egg temperature in both species fluctuated significantly, affected by many factors. Egg temperature increased with increasing ambient temperature, it...
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Effect of incubation temperature on growth of the working and conducting myocardium in the embryonic chick
Skuhrová, Kristýna ; Sedmera, David (advisor) ; Gregorovičová, Martina (referee)
It was shown almost 50 years ago that hypothermic incubation of chicken embryos results in a reduction in the size of embryos and an increase in the heart weight, presumably by hypertrophy (increase in cell volume). The chicken embryos were incubated in normothermia (37.5 ř C) and hypothermia (33.5 ř C) from the eleventh embryonic day. On the 17th day, the embryos were weighed and then their hearts were weighed. In agreement with the previous results, hypothermic embryos were 29% smaller and their hearts 18% heavier. The heart-to-body weight ratio was 67% higher in the hypothermic group. The measured cell size was very similar in the target areas and it was also between the two groups. The left ventricle width was twofold that the right one and the difference was not significantly higher in the hypothermia model. Purkinje fibers, the terminal part of the conduction system, were smaller than the working cardiomyocytes. Purkinje fibers were slightly enlarged after hypothermic incubation. The proliferation rate was measured by immunohistochemical labeling of anti-phospho histone H3. The experimental group showed much higher proliferation rate; it reached statistical significance in the right ventricle. Thus, hypothermic incubation resulted in increased growth of embryonic heart based on hyperplasia...
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The role of partial incubation in birds
Březinová, Monika ; Javůrková, Veronika (advisor) ; Sedláček, Ondřej (referee)
It was documented that many species of birds incubate their clutch before the clutch completion. This behaviour called partial or intermittent incubation usually takes only few hours per day. Eggs in clutch are from the time of laying until the time of full incubation exposed to many negative environmental factors and disturbances. These factors may reduce the viability of the embryo and brood survival. It is therefore predicted that birds use partial incubation as a protection against these negative factors. Most probable functions of partial incubation are a protection against clutch predation, intraspecific and interspecific brood parasitism, and antimicrobial actions linked with reduction of potentially harmful microorganisms on the eggshells and/or activation of proteins with antimicrobial potential in egg's yolk and albumen. This bachelor thesis summarizes overall knowledge of partial incubation, with special emphasis on its incidence and functions in birds. Moreover, this thesis reviews the problematics of synchronous and asynchronous hatching of partially incubated clutches. Although, based on literature review, partial incubation has strong impact on overall reproduction success in birds, study of this incubation behaviour is still neglected and more attention should be paid on comparative...
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Incubation effort in Common Pochard and its determinants
Drekslerová, Šárka ; Hořák, David (advisor) ; Musil, Petr (referee)
Incubation of avian eggs is an energy demanding process. Incubating parent faces a conflict between investment into optimal thermal conditions for developig embryos and meeting of own energy requirements. This applies especially in uniparental incubators such as ducks. During incubation, female utilizes energy from fat storage or actual food intake. The proportion of energy used from food than may reflect the time spent by female on the nest. The utilizing of these both sources ratio plays a role in time spent on nest. The aim of the thesis was to describe an incubation rhythm in females of Common Pochard (Aythya ferina) and relate them to climatic variables and changes in body mass. Data were collecetd for three years in the Poodříí Landscape Protected Area at free-living females. We placed a weighting mechanism under the nest with conected datalogger recording voltage variations, which offered me an information about female body mass and time and duration of recesses. Incubation rhytm of females was described by time spent on time ("incubation constancy"), recess frequency and recess duration. Females left the nest most grequently at night-time and during dawn and dusk. Probable explanation of this pattern is better food availability in the night-time and lower risk of nest predation by predators...
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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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