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Intraspecific and intraclutch variability of avian egg
Králová, Barbora ; Jelínek, Václav (advisor) ; Sedláček, Ondřej (referee)
Egg-laying birds have a huge variation between species in terms of number, size, pigmentation, but also in the speckled nature of the eggs. Bird eggs vary not only between species, but also within species, even within a clutch. It is only recently that more speculation has begun about the possible causes of intraspecific variation. Hypotheses about intraclutch variation started to emerge even later. This thesis presents and describes some of the hypotheses dealing with egg variability. One of the most significant factors affecting intraspecific variability is food availability, which in turn affects female fitness. For intraclutch variability, most studies focus on the difference between the last egg and other eggs within the clutch. In many cases, the last egg has a size difference, but also a different amount of pigment compared to the other eggs in the clutch, which are not significantly different from each other.
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Physiological aspects of the variability in eggshell pigmentation
Mengr, Jan ; Javůrková, Veronika (advisor) ; Krist, Miloš (referee)
The avian eggshell colouration is caused by specific pigments deposited into the eggshell. These pigments differ in colour, chemical structure and the eggshell deposition place. The function of the eggshell pigmentation is traditionally considered to have cryptic or thermoregulatory role. However, most recent hypotheses provide a new perspective on the function of eggshell pigmentation. As between species variability in the eggshell pigmentation is under strong genetic control, within species variability is considered to be a result of adaptation to environmental factors affecting physiology of female bird. This work focuses on the description and characteristics of particular eggshell pigments, their synthesis, deponation process and also the importance of variability in the avian eggshell pigmentation and its physiological aspects. Powered by TCPDF (www.tcpdf.org)
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