National Repository of Grey Literature 44 records found  1 - 10nextend  jump to record: Search took 0.01 seconds. 
Category discrimination in avian predators: formation of natural categories of unpalatable prey
Zíková, Markéta ; Exnerová, Alice (advisor) ; Sedláček, František (referee)
Ability to categorize objects to classes and react to members of one class similarly is important for animals, for example to facilitate discrimination between palatable and unpalatable prey. Objects are typically categorized according to their common features. Birds mainly use visual perception and so their prey also signals its unpalatability visually, through aposematic coloration. We studied the ability of great tits (Parus major) to categorize prey into classes of palatable and unpalatable according to its appearance. Birds were divided to three experimental groups, each tested with different categories of prey. First group was trained to discriminate between aposematic species of true bugs (Heteroptera) and non-aposematic species from other insect taxa. Second group was trained to discriminate non-aposematic species of true bugs and species of other insect taxa and the third in discrimination of pseudocategories, consisting of randomly assigned stimuli from the first experimental group. Tested birds were wild-caught adults and naïve, hand-reared juveniles. Juveniles were tested only in first two experimental groups. All birds were first trained in discrimination between the two categories and then tested in a generalization test with new stimuli. Both adults and juveniles learned to...
Phylogenetic relationships and evolution of the genus Acomys (Rodentia: Muridae)
Palupčíková, Klára ; Frynta, Daniel (advisor) ; Sedláček, František (referee) ; Mazoch, Vladimír (referee)
The geographical distribution and phylogeny of the spiny mice of the genus Acomys Geoffroy I., 1838 remains a controversial and open topic. This doctoral thesis deals with the intraspecific structure and geographical distribution of the genus Acomys from the northern, eastern, central and southern parts of Africa, the Mediterranean islands of Cyprus and Crete, the Turkish coast, the Arabian and Sinai Peninsula and Iran, using molecular analyzes. Molecular analyzes were based on both the mitochondrial gene sequences of the D-loop genes (publication I.) and cytochrome b, as well as the nuclear sequences of the Intraretinal Binding Protein gene (IRBP) (publication IV) and recombinant activation gene 1 (RAG1) (publication II.). Furthermore, the data were subjected to phylogenetic analyzes using the Maximum Probability, Bayesian, Maximum Parsimony, and Minimum Evolution analysis. The results of mentioned analyses confirmed that the Afro-Mediterranean Acomys cahirinus and Asian Acomys dimidiatus are clearly separated. The large similarity between the haplotypes of continental Africa and the northern Mediterranean (A. cahirinus sensu stricto) supports the hypothesis that the ancestors of A. nesiotes, A. cilicicus and A. minous are very likely to spread as commensal populations, thereby challenging their...
Ontogeny of animal personality
Pšeničková, Eliška ; Landová, Eva (advisor) ; Sedláček, František (referee)
Personality, consistent differences among individuals in their behaviour across time and contexts is a popular topic that is being addressed in a large number of studies. However, there are not many studies describing the development of personality over a longer period of time. The most relevant factors for development are: mean-level consistency (also called normative consistency), differential consistency (also called repeatability), structural consistency, and individual stability. Personality is generally more plastic in juveniles, where behavior is often more intense, in the sense that they are bolder, more aggressive/active/explorative, and over time, as individuals mature, plasticity and intensity of behavior decreases. Adolescence is a period in which behavior is often restructured and thus is not stable and consistent at this life-stage. However, behavior does not necessarily change during ontogeny, it may remain unchanged, or the intensity of behavior may also increase with age. Selected models describing the ontogeny of the animal personality are not sufficient and new ones need to be formulated. These should include more variables, for example genetic or maternal factors. This work is a review of studies about ontogeny of animal personality. KEY WORDS: Personality, ontogeny,...
Mice and Rats: Space, Smell and Methods of Detection
Kaftanová, Barbora ; Frynta, Daniel (advisor) ; Sedláček, František (referee) ; Špinka, Marek (referee)
The coexistence of humans and rodents lasts from the beginnings of the history of agriculture. Many rodent populations accepted to synanthropic way of life and as commensals accompany human societies until today. In the first study we wanted to find out, how the evolution of non-commensal rodent species, a Cypriot mouse (Mus cypriacus), was influenced by people. This endemic island species evolved on the Cyprus Island without presence of any mammalian competitors or predators. In last 10.000 years humans arrived on the island, bringing several mammalian species, which affected the environment markedly. A black rat (Rattus rattus) is now dominant species there and presumably it is an important competitor for the Cypriot mouse. We supposed that the mice should avoid its odour. Nevertheless the rats odour was preferred by the mouse, probably as an odour of phylogenetically related species. On the contraty, the odour of domestic cat (species, which is also widespread on the island), was avoided. In conclusion, the long-term isolation from mammalian predators did not affect the antipredatory reactions of the Cypriot mouse. Our next study was focuse on changes in behavioural strategies of different populations of mice: the main question was how the commensal way of life affects their exploratory...
Inter-individual differences in behaviour of laboratory rats
Rudolfová, Veronika ; Nekovářová, Tereza (advisor) ; Sedláček, František (referee)
Number of studies report that even when experimental animals are subjected to the exact same conditions, they differ in their behaviour. If these differences were stable in time and across several experimental procedures, we could talk about personality. This diploma thesis studies inter-individual differences in behaviour of laboratory rats (Long Evans strain) in a series of experiments conducted in early ontogeny and in adult age. Apart from analysing inter-individual differences in behaviour and personality of experimental animals, this thesis has two main aims. The first aim is assessing stability of inter-individual differences in behaviour throughout ontogeny. The second aim is to explore possible link between inter-individual differences in behaviour and performance in cognitive tests. We confirmed the existence of inter-individual difference in behaviour in laboratory rats. In this thesis we were, however, not able to assess personality of experimental animals. The differences in behaviour were best described by behaviour in Open field test and Elevated plus maze test. Our results also show marked differences between successive trials of these experiments. We also report that performance in Active allothetic place avoidance is not linked to performance in Morris water maze, even though both...
Effect of social learning on avoidance of aposematic prey in avian predators
Bělová, Magdalena ; Exnerová, Alice (advisor) ; Sedláček, František (referee)
Social learning is a topic of many studies. We tested the effect of social learning on the acquisition of avoidance against aposematic prey. We have chosen wild-caught adult and naive hand-reared juvenile great tits (Parus major) as a model predator species, because their individual avoidance learnig of aposematic prey is well-studied. We used red and green paper dummies of bugs with a mealworm (Tenebrio molitor) stuck underneath as an artificial prey. Mealworms were soaked in water or in bitter-tasting solution of quinine. We used two types of conspecific demonstrators - naive birds that showed aversive reactions while tasting an unpalatable prey and experienced birds that were trained not to handle the unpalatable pray at all. We compared effects of both demonstrators on discrimination learning and we tested whether these effects differ in adult and juvenile birds. Observing an experienced demonstrator had an effect on the performance of observers at the beginning of learning process. The observers did not reject the unpalatable prey completely, but the number of trials in which they correctly chose the palatable prey was higher in comparison with birds that observed naive demonstrators and birds from the control group with no demonstrator. Latencies to handle the unpalatable prey in the first...
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...
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...
Morphometric analysis of western palearctic representatives of the genus Apodemus: from determination to ecomorphology
Mikulová, Pavlína ; Frynta, Daniel (advisor) ; Macholán, Miloš (referee) ; Sedláček, František (referee)
Summarv ThePhDthesisisbasedonthefollowingpapers: Tnsr or cHARAcTER DISpLACEMENTrN URBAN populATroNs oF APODEMUSSYLVATICUS MikulováP.& FryntaD.200l CanadianJournalofZoology79:794-801 We studiedthewood mouse,Apodemussylvaticus,inhabitingparks, cemeteries,suburbanwoods and other green areas in the city of Prague. To assess the character displacement and (or) release hypothesiswe compared seven samples from local populations occurringsympatricallywith Apodemusflavicollis with ten samples from thoselocalities in which A.flavicoltis hasneverbeenrecorded. The analysis included 1410 specimens of A. sylvaticrzscollected duringthe years 1980- 1990. Seventeenskull andbody characters weremeasured.Then the datawere ageor size adjusted,and treated by principal component analyses. Factor scores were fuither subjected to statistical testing. Although the results revealed a considerablevariation among localities, they did not suggest character displacement and (or) release. A. sylvaticus from populations sympatric with l. flavicollis were morphometrically similar to their conspeciÍicsfrom otherpopulationscollected at the periphery of the city. However, slight but statistically highly significant differenceswere found betweensamples from localities in the city centreand those from the periphery. This phenomenon may be...
Evolutionary consequences of species specific learning strategies: importance of processes resulting in food aversion and special case of social transmission
Landová, Eva ; Fuchs, Roman (advisor) ; Komárek, Stanislav (referee) ; Sedláček, František (referee)
t t Summary This PhD. thesis contributesto the investigationof aposematism- the phenomenonexplaining occuÍTenceof warning coloration in nature. Aposematismis anantipredatorystrategyousuallybasedonpredatorlearning to avoid a noxious prey with a conspicuoussignal. However, not only particularaspectsof aposematicprey signalling (waming colour pattern, conspicuousness,unpalatability),but also predator'spsychologyleadingto avoidancebehaviouris animportantfactorin theevolutionof aposematism. The differentialspecies-specificresponseof nine speciesof our conrmon passerine birds to living aposematicprey (the ťrebug) and correspondingunderlyingvariationin predator'secolory requirements has beenstartingpointof thisPhD.thesis. The next partsof the presentthesishavebeenfocusedmainly on determinationof thesespeciesthat respondspositively (throughoutinnate biases,betterlearningor memoryetc.)to the warningsignalof aposematic prey. The diversity of psychological processes leading to avoidance behaviourin thesespecieshas beenassessed.Firstly, we investigateif the avoidancebehaviouris acquiredby learningor ifthe preyis avoidedon the basisof innatebiasesin severalspeciesof family Paridae. Thenwe focused onmodeof avoidanceleaminganddurabilityof acquiredbehaviourin model species(greattits).The changesin memoryfor...

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4 SEDLÁČEK, František
2 Sedláček, Filip
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