|
|
Diverzita kryptosporidií u pěvců
LIMPOUCHOVÁ, Zlata
This study was aimed on research of biology and diversity of Cryptosporidium in perching birds (Passeriformes). Presence of Cryptosporidium oocyst and specific DNA in faecal samples was detected by microscopy and molecular methods using nested PCR. Biological properties and intensity of infection of Cryptosporidium were examined and described in both experimentally and naturally infected animals.
|
|
|
Behaviour of avian predators to seed bugs (Lygaeoidea): effectiveness of chemical defence
Chalušová, Kateřina ; Exnerová, Alice (advisor) ; Sedláček, Ondřej (referee)
By warning signalling prey advertises its unpalatability to the predators. Typical examples are true bugs (Heteroptera) combining optical and chemical signals. The aim of this study was to find out the effectiveness of chemical defence against wild-caught adults of great tits (Parus major) and blue tits (Cyanistes caeruleus) and towards hand-reared juveniles of great tits. The tested prey were adults and larvae of two invasive species of genus Oxycarenus (Heteroptera: Oxycarenidae) (aposematic O. lavaterae, non-aposematic O. hyalinipennis), adults of Horvathiolus superbus (Heteroptera: Lygaeidae) and crickets (Gryllus assimilis) as a control prey. We were focusing on the influence of seed bugs to the initial reaction, the learning process and to the displays of discomfort behaviour in tits. Reactions affected by the tit species, age and sex were compared in adults. Juveniles were divided into two independent experimental groups, one group was offered adults of genus Oxycarenus, the second was offered sunflower (Helianthus sp.) or Digitalis sp. seed fed adults of H. superbus. The first bug offered did not elicit an initial aversive reaction in tits, but birds reacted aversively to the bugs after having further handling experience. All juveniles, contrary to the adult tits, attacked at least one bug...
|
|
|
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...
|
|
| |
|
|
Sperm phenotype and it's relationship to individual condition
Köstelová, Linda ; Svobodová, Jana (advisor) ; Pavlína, Pavlína (referee)
Animals are known to have evolved many different characters in order to improve their chances during the sexual selection. These secondary sexual characters should correlate with given male´s quality of ejaculate, according to previous research. The literal part of this paper shows us, that the longer the sperm was, the faster, more viable and agile it was. There was a connection between the viability and the length of the middle part of the sperm, that holds the mitochondria. At the same time, sperms with longer tails were faster, as oppose to those with bigger heads, that were slower. This paper was meant to clarify the influence the sperm phenotype on male's ejaculate. For this paper, which focuses on Great tit, the sperm length was chosen as the character of quality. Not only the length of the whole sperm, but also the length of all of its parts were measured. Every one of these parts is associated with the movement and the viability of the sperm in its own way. We tested whether the length of the sperm correlates with characters of the condition or not. The characters we had chosen for this were the length of melanine ornament, the weight of the male, the length of tars and number of leukocytes in blood. The results show that the length of the sperm head correlates with the length of melanine ornament of Great tit. We did not find any other connection among the other secondary sexual characters we had chosen.
|
|
|
Melanin-based ornaments of birds and their relationship to individual condition
Straka, Antonín ; Svobodová, Jana (advisor) ; Karlíková, Zuzana (referee)
This thesis summarizes findings from literature about the melanin pigment and its properties, melanogenesis, factors affecting the synthesis and tissue deposition of melanin, methods for analysis of ornamental traits of birds, and the relationship of melanin-based ornaments and individual condition. Current studies show that the expression of melanin plumage can be condition-dependent; size or chroma of ornaments frequently signals individual condition. The relationship between condition indicators and the melanin pigment is found more often in achromatic species than in species with melanin- and carotenoid-based plumage. There's a lack of research dealing with pheomelanin ornaments.
Statistical analysis of data obtained from adult male great tits (Parus major) captured during the nesting seasons 2014 and 2015 on sites Čimický háj and Ďáblický háj in Prague was carried out to test the relationship between the size of the melanin-based breast stripe and standardized weight, absolute leukocyte count and tarsus length. Results didn't confirm a link between the area of the breast ornament and analyzed indicators of condition. Future research will take into account other condition parameters which could contribute to explain the role of the breast stripe in sexual selection in the great tit.
|
|
| |
|
|
Recognition of inconspicuous prey: importance of additional visual cues
KARLÍKOVÁ, Zuzana
The ability of wild caught great tits (Parus major) to discriminate between equally coloured edible (roach - Blaptica dubia) and inedible prey (firebug - Pyrrhocoris apterus) was tested with respect to other visual traits (shape of legs, antennae,means of locomotion). To simulate more natural conditions, three different experiment types were carried out. Prey was presented either alternately (first roach or firebug) or simultaneously. Additionally, the effect of learning and memory was tested by the use of trial repetition during one session, and session repetition after one week.
|
|
|
The great tit (\kur{Parus major}) as a model species in spatialy cognitive tasks
NÁCAR, David
In this thesis the spatial cognitive experiment with great tits (Parus major) as a model species is described. In this experiment tits learnt to respond to one of four response keys according the presented stimuli. Two types of stimuli were used: one of them contained configural information about response keys, but the other didn´t. The experiment tested the difference of using these two types of spatial information in great tits in two experimental designs. In the first design stimuli were presented in computer screen, in the other they were presented in the floor of experimental chamber. The thesis then discusses the performance of tits in two types of stimuli and two versions of experimental design and compares these results with pigeons in similar experiment.
|
|
|
Key features and prototypes in visual predator recognition - laboratory experiments with Great Tit (\kur{Parus major})
TUMOVÁ, Petra
Categorization of predators is fundamental for birds? life. However, the mechanism is not well explained yet. Two basic theories of categorization were tested in the laboratory conditions, where we have the possibility to focus on the behavior of each individuum. In the experiments we focused on the relevance of the key features and colour patterns. The responses of the Great Tit to variously modified dummies of Sparrowhawk were observed. The results confirm that the bird does not recognize the predator only on the basis of the key features and the colour patterns have a essential influence on the categorization. Categorization of the predator is a complex process and it cannot be explained only on the basis of one psychological theory. A combination of the key features and a prototype of a particular category learned throughout its life is probably used.
|
guest ::
