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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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Neural Basis of magnetic compass orientation in C57BL/6J mice
Bláhová, Veronika ; Němec, Pavel (advisor) ; Druga, Rastislav (referee)
The ability to perceive the Earth's magnetic field has been demonstrated in a variety of animals, including representatives of all five classes of vertebrates. The physiological mechanisms underlying magnetic field sensation, however, remain largely unknown. Behavioral, physiological, neuroethological studies and studies using early response genes as neuronal activation markers indicated that a major role in the perception and processing of magnetic information play trigeminal, vestibular and visual systems. Subsequently, magnetic information seem to be integrated with multimodal sensory and motor information within the hippocampal-entorhinal system. In the majority of studies, however, birds have been used as model organisms. In this work I analyzed the neural substrate of magnetic compass orientation in the mouse strain C57BL/6J using markers c-Fos and Egr1. I found that all the aforementioned systems contain neurons responsive to the experimental magnetic fields. This finding demonstrates a complex processing of the magnetic information at level of the central nervous system.
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Male parental behaviour in rodents
Kopcová, Kateřina ; Frynta, Daniel (advisor) ; Pavelková, Věra (referee)
Paternal care is uncommon in mammals where males are more often involved in sexual competition for females than in providing care for their own offspring. Howewer some species present greater form of patertal care than metabolic investment in sex cells, and most of the time, this phenomenon is associated with a monogamous mating system. The direct costs of paternal behaviour are relatively well documented in primates, despite little research has explored these effects in monogamous rodents and even less in some polygynous rodents. The relative rarity of monogamy and associated paternal care has been interpreted in light of the relationship between parental investment and sexual selection. The major drawback of such bias is that most current hypothesis on rodent paternal behaviour are based mostly on data optained from a few species from temperate regions, mainly cricetids and murids, performed in controlled environment and in special conditions. Powered by TCPDF (www.tcpdf.org)
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Male parental behaviour in rodents
Kopcová, Kateřina ; Frynta, Daniel (advisor) ; Pavelková, Věra (referee)
Paternal care is uncommon in mammals where males are more often involved in sexual competition for females than in providing care for their own offspring. Howewer some species present grater form of patertal care than metabolic investment in sex cells, and most of the time, this phenomenon is associated with a monogamous mating system. The direct costs of paternal behaviour are relatively well documented in primates, despite little research has explored these effects in monogamous rodents and even less in some polygynous rodents. The relative rarity of monogamy and associated paternal care has been interpreted in light of the relationship between parental investment and sexual selection. The major drawback of such bias is that most current hypothesis on rodent paternal behaviour are based mostly on data optained from a few species from temperate regions, mainly cricetids and murids, performed in controlled environment and in special conditions.
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The morphology of penis and baculum in selected genera of African rodents
HORÁKOVÁ, Sylvie
This master thesis consists of two main parts. The first of them represents a compilation of information and facts about baculum, specifically about its presence, function and evolution in mammals. Further I focused on biological characters of five genera of African muroid rodents (Acomys, Aethomys, Gerbilliscus, Saccostomus, Stenocephalemys), which were analyzed in detail in the second part of my thesis in respect of their penial and bacular morphology.
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