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Effect of incubation temperature on phenotype in mallard
Cílková, Martina ; Hořák, David (advisor) ; Krist, Miloš (referee)
The influence of incubation temperature on bird neonate phenotype is widely studied. In waterfowl (Anatidae), maternal effect can be divided to two main parts: clutch formation and its incubation. Therefore, waterfowl are a good model for this type of study. The egg temperature can strongly influence embryo development and survival of the hatchlings. The goal of this work was to examine the effect of incubation temperature on hatchability, incubation length, sex ratio and phenotype of European Mallard ducklings immediately after hatching. Eggs were randomly placed in one of six incubation temperatures, which ranged from 35 to 39 řC. This range corresponds with temperature range in natural mallard nests in the Czech Republic. Eggs were then artificially incubated. Newborn hatchlings were weighted and their structural size was measured, then they were killed. Some hatchlings from incubation temperatures 35.5, 36 and 37 řC were used to examine residual yolk sac mass and basic chemical composition of the yolk-free body. Hatchability was markedly lower in both extreme temperatures (35 and 39 řC). Incubation length significantly decreased with increasing incubation temperature. I failed to prove the influence of incubation temperature on hatchling body mass, but I found temperature-dependent changes of...
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The effect of incubation temperature on cognition and brain cellular composition in geckos Paroedura picta
Polonyiová, Alexandra ; Němec, Pavel (advisor) ; Sedláček, František (referee)
The effect of incubation temperature on different morphological, physiological, cognitive and behavioral characteristics in reptiles is a well-studied topic, although the underlying mechanism leading to the differences between individuals incubated at different temperatures remains largely unknown. In this thesis I studied the effect of incubation temperature on cognitive abilities and the number of neurons and non-neuronal cells in the gecko Paroedura picta incubated at two different temperatures, 24řC and 30řC. The geckos were tested in two cognitive tasks with simulated predatory attack. 14-day-old hatchlings were tested in a Y-maze, while 6-months-old geckos were tested in an arena with shelters of different colors. After testing, the number of neurons and non- neuronal cells in several parts of the brain were estimated using the isotropic fractionator in selected individuals. Although incubation temperature did not affect the success in the cognitive task in hatchlings, it did affect the total time needed to find the shelter. This difference remained significant also in adult geckos. The number of neurons, which was used as a proxy for the information processing capacity of the brain, did not affect success in the cognitive tasks. However, absolute brain size correlated with success in the...
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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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Effect of incubation temperature on phenotype in mallard
Cílková, Martina ; Hořák, David (advisor) ; Krist, Miloš (referee)
The influence of incubation temperature on bird neonate phenotype is widely studied. In waterfowl (Anatidae), maternal effect can be divided to two main parts: clutch formation and its incubation. Therefore, waterfowl are a good model for this type of study. The egg temperature can strongly influence embryo development and survival of the hatchlings. The goal of this work was to examine the effect of incubation temperature on hatchability, incubation length, sex ratio and phenotype of European Mallard ducklings immediately after hatching. Eggs were randomly placed in one of six incubation temperatures, which ranged from 35 to 39 řC. This range corresponds with temperature range in natural mallard nests in the Czech Republic. Eggs were then artificially incubated. Newborn hatchlings were weighted and their structural size was measured, then they were killed. Some hatchlings from incubation temperatures 35.5, 36 and 37 řC were used to examine residual yolk sac mass and basic chemical composition of the yolk-free body. Hatchability was markedly lower in both extreme temperatures (35 and 39 řC). Incubation length significantly decreased with increasing incubation temperature. I failed to prove the influence of incubation temperature on hatchling body mass, but I found temperature-dependent changes of...
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