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Cognitive abilities in reptiles: individual learning ability vs. interspecies comparison
Víšková, Linda ; Landová, Eva (advisor) ; Kverková, Kristina (referee)
The cognitive abilities of "reptiles" have long been a neglected topic compared to research on cognition in two other groups of tetrapods - mammals and birds. Recently, however, studies testing selected aspects of various cognitive abilities in "reptiles" have become quite abundant. In this thesis, the different types of cognitive tasks studied were determined (focusing on numerical abilities, spatial learning, reversal learning, visual discrimination, social learning, "problem-solving" or operant conditioning) and then the methods of testing them in "reptiles" were discussed in detail. Subsequently, within the paraphyletic group "reptiles", the given cognitive abilities for each family (and specific species) were mapped with respect to their phylogeny. A general problem in some studies was the smaller number of subjects tested (minimum 1, maximum 559, median 15) relative to the often great number of factors studied (minimum 1, maximum 14, median 4) and the wide interindividual variability in cognitive performance. Although the amount of work on the cognitive abilities of "reptiles" has been rising over the last decade, qualitative analysis suggests the presence of simpler types of cognition. A quantitative or phylogenetic analysis of "reptilian" cognitive abilities has so far been precluded by low...
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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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Interspecific comparison of social learning of food aversions in tits
Mitlenerová, Barbora ; Exnerová, Alice (advisor) ; Sedláček, František (referee)
Social learning in animals is a frequently studied topic, including birds. Great tits belong to frequently tested passerine species in this context. For this experiment we have chosen another tit species as model birds - adult and juvenile blue tits (Cyanistes caeruleus) and coal tits (Periparus ater). We tested an effect of social information on discrimination learning between palatable and unpalatable prey. Red and green artificial prey items resembling shieldbugs with a mealworm glued underneath were offered to birds. One variant was palatable, the other was unpalatable, soaked in bitter substance. Experimental groups were allowed to observe a pretrained tutor of the same species choosing palatable prey variant and rejecting the unpalatable one. The birds were then subjected to an individual discrimination learning task with simultaneously offered palatable and unpalatable prey items. The control group was not allowed to observe tutor and learned only individually. On the following day, all birds participated in a memory test. We tested if social information has an influence on avoidance learning in juvenile and adult birds of both species. We found that both species of tits were similarly successful in discrimination learning and there was no difference in success in performance between adult...
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Effect of type of discrimination task on rate and effectiveness of discrimination learning to avoid aposematic prey in avian predators
Jůnová, Lenka ; Exnerová, Alice (advisor) ; Sedláček, Ondřej (referee)
During the proces of learning to distinguish between edible and inedible prey, predators can encounter different types of prey either sequentially (one at a time) or simultaneously. Sequential as well as simultaneous presentation are used as experimental designs for testing discrimination learning of bird predators in relation to aposematic prey. These tasks can differ in difficulty level for predator which can affect test results; however, rate and effectivity of discrimination learning in sequential and simultaneous tasks have never been experimentally compared. We tested effect of type of discrimination task on effectivity of discrimination learning and memorability of prey discrimination in adults and juveniles great tits (Parus major) in two sequential tasks (regular and random) and one simultaneous task (multiple- choice). The birds learned to discriminate between edible and inedible artificial prey on the first day, and we investigated memorability of prey on the second day. We used colour (alternative red/green) or pattern (alternative dots/stripes) as discrimination cue. Results showed that tits learned to discriminate by colour cue better than by pattern cue. Adult tits learned to discriminate better than juveniles independently on task type. Effect of age and sex was shown in some tasks...
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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...
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