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Body size as an implicit factor: case studies of life-history strategies and behaviour
Šimková, Olga ; Frynta, Daniel (advisor) ; Sedláček, František (referee) ; Rehák, Ivan (referee)
Body size has a potential to influence almost any trait in animal biology. The thesis contains four case studies (I - IV) covering four various situations and four various taxa, mainly squamate reptiles (Lepidosauria). Body size is a connecting factor for all these studies, in which I and my co-authors tried to elucidate various implications of body size. I. The sex ratio in Cuban boa (Chilabothrus angulifer) litters is often male or female biased. The neonates are so large, that are able to accept the same type of prey as are adults (in contrast to the other Chilabothrus species). We found that both the sexes are of the same size and shape at birth. Large size of the neonates a long lifespan lead to considerable generation overlaps. This could clarify our findings that small females produce sons whereas the larger ones deliver daughters. Males are smaller than females, probably also less philopatric and refuse food during breeding season. We can conclude that females manipulate the sex ratio of neonates according to its own body size, in order to decrease the probability of competition with their own offspring. II. Mangrove-dwelling monitor lizard (Varanus indicus) shows one of the greatest degrees of sexual size dimorphism among monitor lizards. We recorded the growth of the individuals from...
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Shell shape variability in selected members of family Geoemydidae
Protiva, Tomáš ; Rehák, Ivan (advisor) ; Šmíd, Jiří (referee) ; Široký, Pavel. (referee)
Turtles always fascinated men primarily by morphology, unique embryogenesis and later also by uncertain phylogenetic position. As this group exists for 200 Mya, with taxon Odontochelys and Proganochelys identified as the first ancestors, recently they are endangered by habitat destruction and hunting for meat. The worst situation is in Asia, with China as the most important consumer of turtle meat and other products. Captive breeding programs may be the only chance for lot of almost extinct species. Proper taxonomic and geographical determination is crucial for correct management of rescue programs. Shell shape variability studied by geometric morphometric method and supported by genetics is the right tool for this task. My thesis is focused on verification of the use of geometric morphometric method for selected species of family Geoemydidae. This family has centre of distribution in Asia and many of its species are endangered by so called Asian Turtle Crisis. We found unusual high occurrence of supernumerary vertebral scute in Morenia petersi. Shape of the carapace and plastron is not affected by presence of this extra scute. There are no significant differences between turtles with additional scute and turtles with normal five vertebral layouts. Scute pattern with supernumerary vertebral scute...
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Ecology,ethology and variability of european green lizard Lacerta viridis in Natural reservation Tiché údolí
Chmelař, Jan ; Rehák, Ivan (advisor) ; Moravec, Jiří (referee)
The European green lizard, Lacerta viridis, is in the Bohemia region stated as critically endangered species. Populations in this region are located beyond the northern border of continuous range of this species and are closely related to the "riverine phenomenon", and deeply engorged river valleys. The chosen locality in Tiché údolí is a subject to a long-term conservational management aimed to strengthen and maintain abundance of the local population. This management is a direct output of a previous study of this population performed in years 1995-1997. Main goal of the presented study is to compare current population characteristics with the older study. The locality has been visited 119 times in years from 2011 to 2014. The studied population now displays higher abundance and inhabits a larger area. The author also performed a spatial analysis of the places with presence of an observed individual in order to determine and evaluate significance of the chosen abiotic factors for habitat discrimination. The results indicate that positive discrimination is based on the presence of a rock debris and a hiding place. Strongest factors towards negative discrimination were high percentages of grass and high vegetation coverage. This study also contains and discusses ecological, ethological and...
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Reproductive strategies in boid snakes
Vejvodová, Tereza ; Frynta, Daniel (advisor) ; Rehák, Ivan (referee)
The important part of life history of species is number and size of offspring, which is limited by size of maternal investment. Family of boas (Boidae) comprises species with various maternal investments. The species of study was Cuban boa (Chilabothrus angulifer) having small litter size, but producing one of the biggest neonates from family Boidae. The aim of the thesis was to analyze relationships between life-history parameters and try to find possible evolutionary causes of this huge maternal investment. Results show, that the female's decision to reproduce is under "Capital breeder" strategy, when size of the female positively influence litter size and offspring size. Surprising result is that smaller (younger) females are producing more sons than daughters in accordance with "Local resource competition" hypothesis. Fitness of the young should increase with birth size. That was confirmed only in interspecific survival rate being very high in Cuban boa. Keywords: snakes, Cuban boa, maternal investment, life history, SSD, sex ratio
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Behavioural correlates of lizard colouration
Bauerová, Anna ; Frynta, Daniel (advisor) ; Rehák, Ivan (referee)
The coloration is a significant animal attribute which can be examined from the view of phylogenesis, ontogenesis, ecology or life-history parameters. In this thesis the method of coloration quantification and pattern complexity was developed, with the focus on Leopard gecko (Eublepharidae) family. are one of the most commonly breeded lizards, the great part of their popularity being due to their attractive "leopard" coloration. Yet we only know a little about their "wild" coloration. They have become an important organism for many etological and physiological experiments, the distinct color pattern change during ontogenesis being especially unusual. These aspects make them an ideal subject for coloration change and affecting parameters analysis. The results of this work show clear ekological pattern for coloration. The amount of black color correlates with the humidity and abundance of vegetation in the habitat of the species. The coloration quantification was also verified using spectrophotometry, which confirmed the original assumptions for colors included in the pattern. Given the absence of UV reflectance in the Leopard gecko pattern, we can assume that the UV spectrum pattern is not an essential parameter. Therefore, the photographies can be used for quantification as well. It is apparent...
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Systematics, Phylogeny and Biogeography of the gecko genus Hemidactylus (Reptilia, Gekkonidae) in Arabia and the Near East.
Šmíd, Jiří ; Moravec, Jiří (advisor) ; Kotlík, Petr (referee) ; Rehák, Ivan (referee)
(in English) Until relatively recently, the gecko genus Hemidactylus was considered to contain only several hard-to-distinguish species in the eastern Mediterranean and the Arabian Peninsula. This was mostly given by the apparent morphological uniformity of the geckos in combination with their often synanthropic lifestyle, which facilitated the dispersal of some of the species over large ranges. However, our understanding of the diversity of the genus was about to change with the onset of molecular phylogenetic methods that became extensively available and routinely applied to tackle the questions of systematics and phylogeny of all kinds of organisms. This thesis focuses on resolving the phylogeny, systematics, and biogeography of the Arabian Hemidactylus. Using an unprecedented sampling of over 500 samples of more than 40 Hemidactylus species from the eastern Mediterranean, Arabian Peninsula, Socotra, North and East Africa and Iran and sequencing up to six genes (two mitochondrial - 12S rRNA, cyt b; four nuclear - cmos, mc1r, rag1, rag2) I reconstructed the time-calibrated phylogeny of the arid clade of Hemidactylus, inferred its complex biogeographical history in the region, and detected seven potentially new species. The results of the biogeographic analyses indicate that the current...
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