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Factors affecting behaviour of avian predators to hoverflies (Syrphidae) and their models (Aculeata)
Truhlářová, Marie ; Exnerová, Alice (advisor) ; Sedláček, František (referee)
Batesian mimicry is an antipredator strategy used by harmless species to mimic dangerous models by their appearance. The so-called imperfect mimics are a phenomenon within Batesian mimicry. It would be expected that Batesian mimics are selected to resemble the model as perfectly as possible. However, in some species the resemblance is very poor. The aim of this study was to test reaction of predators towards a textbook example of Batesian mimics with imperfect mimicry, i.e., hoverflies (Syrphidae) and to verify some of the hypotheses describing imperfect mimicry. We conducted two experiments in which the model predators were great tits (Parus major). The topic of the first experiment was the effect of diversity of models on categorization and generalization of hoverflies. Birds were divided into two groups, with the first group receiving high diversity of models (10 species of Hymenoptera) and second group receiving low diversity of models (2 species of Hymenoptera). There were two parts of this experiment. Categorization training when great tits learn to discriminate between two categories of prey, palatable and unpalatable and generalization test, when great tits generalized their experience from categorization training to novel prey. Palatable prey was represented by non-mimetic flies (Diptera),...
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Evaluation of Business Performance Through Financial Analysis Tools
Sedláček, Filip ; Toman,, Petr (referee) ; Ptáček, Roman (advisor)
This bachelor’s thesis focusses on the evaluation of business performance using tools of financial analysis during the period 2016 – 2020. The theoretical part describes individual indicators and methods that are explained and subsequently used in this work. The second part of the thesis discreetly presents analysed company to which mentioned above indicators from the theoretical part are applied. The last part of this thesis presents the overall evaluation of the results of financial analysis including the author’s suggestions to improve financial situation of the company.
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Lachrymal secretion in tenrecs: physiological, behavioral and phylogenetic contexts (Tenrecinae, Afrosoricida)
Bálek, Jiří ; Horáček, Ivan (advisor) ; Sedláček, František (referee)
The secretion of white liquid around the eyes and nose with a spiny tenrecs Echinops telfairi and Setifer setosus mentions for the first time Poduschka in 1974, but until now this phenomenon in these species no one paid any detail. Similar secretion was described in Mountain beaver or by shrews. The impetus for shedding the excitement caused by the presence of an individual female or another male or its odor. Males secretions also used for marking territory. A total of 70 samples of eye secretions from ten male Echinops telfairi during the entire active season (from March to October) have been collected within this study. For protein detection method was used two-dimensional polyacrylamide gel electrophoresis (2D PAGE) and subsequent identification by mass spectrometry. An autopsy of the eye area was performed for representatives of all four genera of the subfamily Tenrecinae (Tenrec, Setifer, Echinops, Hemicentetes), died in Pilsen Zoo. It was found that a) species of pinholes that produce ocular secretions are significantly higher tear and Harder's gland, b) secretions contain lipocalins - proteins with the ability to transmit pheromones and other hydrophobic molecules, c) secretions of the orbital region having a different composition than the secretions from the nasal area (significantly lower protein...
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A test of "object permanence" in Paridae and effect of neophobia and individual explorative strategies on success in solving object permanence tasks
Marhounová, Lucie ; Landová, Eva (advisor) ; Sedláček, František (referee)
Object permanence (OP) is a cognitive ability that enables animals to mentally represent the existence of hidden objects even if they can not be perceived by senses. In humans, OP develops during six qualitative stages, in which the understanding of relationships between objects in space and time changes. Current research shows that primates, some carnivores and several species of birds also acquire various degrees of this ability depending on their social life and foraging strategies. Many studies of OP have focused on food-storing birds but yet only in the Corvidae family. Therefore we decided to test this ability in two species of the Paridae family, food-storing coal tit (Periparus ater, N=23) and non-storing great tit (Parus major, N=24) to find out which stage they can achieve and whether there is a difference between these species in relation to their caching ability. Our results suggest that food-storing coal tits search for completely hidden objects significantly better than great tits. Most of the great tits were not able to solve this task. However, the upper limit for both species is probably Stage 4 because coal tits probably solved OP tasks with more screens randomly or used alternative strategies rather than mental representation. Substantial interindividual variability in the...
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Contribution of social dominance on performance in spatial cognitive tasks in pigeons
Janská, Iveta ; Landová, Eva (advisor) ; Sedláček, František (referee)
Diploma thesis generally compares individual success pigeons in spatial tasks of varying complexity (in a role that requires abstraction of visual stimuli representing spatial relationships on the touch screen using two different strategies and spatial search task the middle plate of a series of plates with different variants of location) with hierarchical status of males and group females. Specifically thesis compares individual success pigeons in spatial tasks of varying complexity. The hardest task requires a certain level of abstraction of visual stimuli representing spatial relationships using experimentally induced two strategies: mapping strategy or specific symbol association with a position in space. The role tests on the touch screen with the help of operant conditionings. Difficulty in various stages of growing, the last stage role does manage only some individuals. Conversely easier task in real space with a bird tasked with finding the midpoint between objects in different variants locations within the arena. The difficulty of the task is not growing, and it can solve some individuals who have not learned operant conditioning if the previous job. Performance in cognitive tasks could be affected by the hierarchical status of the animal in the group. Pigeons position in the hierarchy has...
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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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Acoustic communication and its variability in selected populations of ground squirrels of the genus Spermophilus
Schneiderová, Irena ; Vohralík, Vladimír (advisor) ; Sedláček, František (referee) ; Špinka, Marek (referee)
The thesis deals with vocalizations produced by Eurasian ground squirrels of the genus Spermophilus. It is mainly focused on inter-species and intra-species variability in acoustic structure of alarm calls which are emitted in presence of predators.The major part of the thesis deals with intra-species variability in acoustic structure of the alarm calls in five Eurasian ground squirrels, Spermophilus citellus, S. taurensis, S. xanthoprymnus, S. suslicus and S. fulvus. It has been confirmed that the alarm calls of these ground squirrels show a high level of species specificity. The thesis further describes another vocalizations produced by three Eurasian ground squirrel species, Spermophilus suslicus, S. citellus and S. fulvus, and shows that with the exception of the alarm calls, vocal repertoires of these three ground squirrels are remarkably similar. The last part of the thesis deals with individual distinctiveness of the alarm calls of three Eurasian ground squirrels, Spermophilus citellus, S. taurensis and S. xanthoprymnus. It has been shown that the alarm calls of these species have a significant potential to encode information about caller identity.
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Factors affecting long-term memory of aposematic signals in avian predators
Skoumalová, Žaneta ; Exnerová, Alice (advisor) ; Sedláček, František (referee)
The ability to memorize and recognize edible prey from inedible prey is essential for an individuals survival. Many species use aposematic signals for their defense. These are most often represented by distinctive colors or contrast patterns. The aim of this study was to find out in which time the memory consolidation for aposematic pray is achieved and if color or pattern increase its memorability. The choosen model species was the Great tit (Parus major). The comparision was done between handreared naïve birds and wild-caught adults of different age and sex. During the discriminatory task of consolidation experiment, birds were simultaneously presented with palatable and unpalatable prey in the form of paper dummies of bugs, differing in color (red versus green). The birds were divided into three groups with a different interval (0, 1 or 3 hours) for consolidation. The results of consolidation test show that adult birds were more successfull in solving the task than juvenile birds. The only difference between the experimental groups was that the group with one-hour interval achieved better results than other groups. The effect of color of palatable and unpalatable prey on discrimination learning was also found only in adults. Memorability of warning signals was tested using paper bugs of...
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