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Optimization of litter size in rodents
Cingelová, Alexandra ; Dušek, Adam (advisor) ; Sedláček, František (referee)
Optimization of litter size can be defined as adjustment of litter size according to actual environmental conditions or condition of mother to reach a compromise between the maximum number of offspring and their individual fitness. Rodents are an ideal taxon to study this topic because of their enormous interspecific variability in life strategies across the whole order. The variation in litter size among rodent species was influenced by countless ecological and social factors during their evolution. These include the geographical location of the breeding populations, various life and reproductive strategies such as r-/K-strategy, the presence of altricial or precocious offspring, various ways of life, the presence of water in the environment, predation rate, hibernation, and sociality. Litter size can be adjusted already before fertilization, for example by choosing a partner, by timing reproduction, condition, age and social status of the mother. Genetic factors affecting litter size are, for example, MHC glycoprotein polymorphism and t-haplotype. Reduction of the litter size may occur before insemination by influencing the ovulation rate, female reproductive hormone levels and exposure to the stressors, during implantation by selective abortion, and postpartum by infanticide, siblicide, and...
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Optimization of litter size in rodents
Cingelová, Alexandra ; Dušek, Adam (advisor) ; Sedláček, František (referee)
Optimization of litter size can be defined as adjustment of litter size according to actual environmental conditions or condition of mother to reach a compromise between the maximum number of offspring and their individual fitness. Rodents are an ideal taxon to study this topic because of their enormous interspecific variability in life strategies across the whole order. The variation in litter size among rodent species was influenced by countless ecological and social factors during their evolution. These include the geographical location of the breeding populations, various life and reproductive strategies such as r-/K-strategy, the presence of altricial or precocious offspring, various ways of life, the presence of water in the environment, predation rate, hibernation, and sociality. Litter size can be adjusted already before fertilization, for example by choosing a partner, by timing reproduction, condition, age and social status of the mother. Genetic factors affecting litter size are, for example, MHC glycoprotein polymorphism and t-haplotype. Reduction of the litter size may occur before insemination by influencing the ovulation rate, female reproductive hormone levels and exposure to the stressors, during implantation by selective abortion, and postpartum by infanticide, siblicide, and...
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Optimization of delivery date in cervids
Schnebergerová, Adriana ; Dušek, Adam (advisor) ; Sedláček, František (referee)
Female mammals adjust their birth date according to actual environmental conditions and their own condition to maximize their reproductive fitness. Optimizing of birth date allows the mothers to maximize not only their own fitness but also the fitness of their offspring. The aim of my bachelor`s thesis is to document the optimization of the delivery date in the deer family (Cervidae), i.e. timing of delivery whereby females can attain successful reproduction. This family is thanks to world-wide areal an ideal taxon for the study of optimization of the delivery date. 40 species and 200 subspecies renders this family one of the most diversified and the most numerous of even-toed ungulates (Artiodactyla). In general, factors that affect the timing of the delivery date are: ecological, behavioral, reproductive, physiological and genetic. These factors include, for example, seasonality, availability and quality of food, condition, social rank and age of the female, the presence of the male and the sex of the offspring. Depending on actual environmental conditions, female deer may either hasten or, on the contrary, delay the delivery date and thus maximize the chances of survival of their offspring. The synchronization of the birth date is another important strategy which allows females to reduce the...
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