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Signaling function of plumage coloration in Yellowhammer males
Kauzál, Ondřej ; Petrusková, Tereza (advisor) ; Šálek, Miroslav (referee)
Sexual selection theory tries to explain evolution of apparently useless traits which mainly developed in males of numerous species. One such trait is also rich and vibrant coloration, typical for many of the bird species. These traits are difficult to be falsified, and therefore they honestly signal quality of the individual. Carotenoid coloration reflects the health condition and melanin coloration the social status, even though this traditional division might not be as strict according to the latest studies. Apart from these ways of maintaining honesty, recent studies are focusing more also on the effect of hormones, mainly two steroids: male sexual hormone - testosterone -, and the "stress" hormone - corticosterone. Both hormones could positively influence male's sexual traits such as ornamental coloration. On the other hand, elevated levels of these hormones possess risk to the organism (higher energetic expenditure, chronic stress), therefore also might potentially become costly. Using photographs of birds in standardized conditions as well as spectrophotometry I analyzed the plumage coloration of males of the Yellowhammer (Emberiza citrinella). Concentrations of testosterone and corticosterone deposited in feathers were analyzed using the LC-MS/MS. Also, for males in breeding season 2015,...
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Characteristics of inter-individual relationship (friend vs. rival) in red deer and its effect on agonistic behavior and endocrinological feedback
Peterka, Tomáš ; Bartoš, Luděk (advisor) ; Fuchs, Roman (referee)
Red deer males aggregate for a major part of a year to bachelor groups. Social position - Rank - is unstable in these groups. Previous experiments revealed that rank modulated by agonistic behaviour influences antler growth and antler cycle timing. Antlers are secondary sexual characteristics of the deer family and one of the fastest growing tissue in the vertebrate taxa. Their development is modulated by androgenic hormone, testosterone. In our experiment, we observed agonistic behaviour of 19 males. They were equipped with GPS collars and regularly handled for blood samples and downloading of telemetrical data. Based on statistical analysis, we found that in our bachelor group 13 stags kept similar interindividual distances which did not exceed 22 metres ("Closest associates"), whereas the rest of the group moved tens of metres away ("Wanderers"). In regard to the number of agonistic interactions and the interindividual relationship, which arose from that, we divided the bachelor group on "Friends" (˂9 interactions) and "Rivals" (≥9). We found that the number of interactions depended on average distance among males in groups divided by dyadic relationship ("Friends" and "Rivals"). With increasing distance, "Rivals" increased the number of interactions, while "Friends" did not show this trend....
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Hormonal changes in strength training
Rafael, Gáll ; Petr, Miroslav (advisor) ; Šteffl, Michal (referee)
Title: Hormonal changes in strength training Objectives: Perform a systematic review of literature dealing with hormonal changes in strength training. Based on the informations from aforementioned literature, describe wheather acute hormonal response after a bout of strength training significantly influence the proces of hypertrophy or not. Hormone testosterone and changes of its concentrations is for this thesis the most important. Methods: Method of traditional review was used in this thesis. Results: The presence of acute hormonal changes occurred in strength training was confirmed in numerous studies. Role of this hormonal response is because of variability in results not very clear yet. Chronicle changes of resting hormonal levels in strength training are not observed according to results of studies. For better understanding of hormonal strength in strength training, another studies have to be executed. Keywords: endocrinal system, strength training, hormonal response, testosterone, hypertrophy.
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Latitudinal trends in avian life-histories
Krejčířová, Zuzana ; Albrecht, Tomáš (advisor) ; Reif, Jiří (referee)
Most studies on bird focus on northern temperate zone species. However, the vast majority of birds occupies tropical environments. In birds, differences between tropical and temperate zone species in various life-history traits have long been assumed. These differences may reflect variation in solving the survival-reproduction trade-off, with temperate species preferring actual reproduction over the survival and tropical species preferring the oposite. In this bachelor thesis I summarize the result of literature search focusing on latitudinal trends in selected life-history traits in birds. In the first part of thesis I provide an overview of differences between the temperate and tropical zone in environmental conditions often assumed to closely affect the evolution of avian life histories. In the second part of the thesis, I focus on particular life-history traits where the differences between tropical and temperate species were detected. Latitudinal trends in chosen life history associated traits (clutch size, longevity and life span, basal metabolic rate) indeed seem to correspond with the general prediction of comparatively slow pace of life in tropical species.
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Changes in Hormone Levels in Female Basketball Players and Their Relationship with Emotional state and Efficiency
Zikánová, Tereza ; Pivoňková, Věra (advisor) ; Hroníková, Linda (referee)
This thesis focuses on women's competition in female basketball players and their hormonal responses to winning and losing. We tested saliva samples of 29 female players for testosterone and cortisol which were collected in three phases: baseline samples, pregame samples and after game samples. In every collection phase we also inquired about the emotional state of mind of the respondents. Players completed a survey examining their subjective evaluation of the match result. We also used statistical data from every match, which provided an objective evidence on the players' usefulness. All the aforementioned variables were examined in relation to the testosterone and cortisol levels. The results have revealed that the cortisol levels are responsive to the match results, whereas the losing players display a significant rise of the stress hormone level after the match. The winners display only a slight increase in the cortisol levels. Testosterone levels did not prove to react to the match results. However, it was discovered that the winners exhibited higher levels of testosterone in all collection phases than their competitors. Nevertheless, the difference between the winners and the losers was not significant in any of the cases. The winners felt more positive after the match than the losers. The correlation...
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Changes in testosterone level in 16-year-old boys in response to experimentally induced jealousy reaction
Enderlová, Jana ; Pivoňková, Věra (advisor) ; Konečná, Martina (referee)
Past research suggests association between basal steroid hormone testosterone level and its changes with some individual characteristics (especially some behavioral manifestations of dominance and aggression) and its changes within male-male competition. This relationship is usually (in accordance with evolutionary theory) interpreted as the consequence of different individual prerequisites (or the degree of individual motivation) for high status position including winning a male- male competition. The aim of this study was to test the adequacy of measuring jealousy reaction in adolescent boys by way of changes in salivary testosterone level and finding their associations with some individual characteristics mentioned by researchers. For the purpose of measuring basal testosterone level before starting the experiment and changes in its level following the jealousy stimulus within a competition for a mate which simulated the internet mating and changes in its level after being informed of their failure in this competition, the boys who participated in our study provided three salivary samples (the samples were provided after 15 minutes after the stimuli). For finding associations of basal and mean testosterone level and these hormonal changes with some individual characteristics, the boys filled in...
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Comparison of the determination of hormones (Follicle stimulating hormone, Luteinizing hormone, Prolactin, Testosterone, Progesteron) by two analytical systems. Converting accredited method and its verification.
Kucejová, Soňa ; Martínková, Markéta (advisor) ; Mrízová, Iveta (referee)
Analytical system ARCHITECT i2000SR was verified according to requirements of ÚLBLD VFN and 1. LF UK laboratory in Prague. Repeatability, intermediate precision, and measurement uncertainty were determined as performance parameters for verification of analytical assays for testosterone, progesterone, luteinizing hormone, follicule stimulating hormone and prolactin. Results of Lyphochek control samples, which were measured, were consistent with values given by manufacture. Repeatability: coefficients of variation for testosterone Lyphochek 1 6,81%, for Lyphochek 3 6,40%, progesterone 2,4% and 1,8%, luteinizing hormone 5,38% and 1,89%, follicle stimulating hormone 5,12% and 3,24% prolactin 1,45% a 1,83%. Intermediate precision: coefficients of variation for testosterone Lyphochek 1 6,02%, Lyphochek 2 3,60%, Lyphochek 3 3,07%, progesterone 7,9%, 4,9% and 5,8%, luteinizing hormone 4,50%, 5,51% and 5,83%, follicle stimulating hormone 4,00%, 3,72% and 4,87%, prolactin 4,60%, 4,20% and 5,00%. Measurement uncertainty: testosterone 6,02%, progesterone 7,9%, luteinizing hormone 5,83%, follicle stimulating hormone 4,87%, prolactin 5,00%. Analytical System Architect i2000SR was compared with previously used ADVIA Centaur system to find out, whether it is possible to convert the method Centaur Testosterone,...
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Changes in testosterone level in 16-year-old boys in response to experimentally induced jealousy reaction
Enderlová, Jana ; Klapilová, Kateřina (advisor) ; Konečná, Martina (referee)
Past research suggests association between basal steroid hormone testosterone level and its changes with some individual characteristics (especially some behavioral manifestations of dominance and aggression) or different outcomes of male-male competition. This relationship is usually (in accordance with evolutionary theory) interpreted as the consequence of different individual prerequisites (or the degree of individual motivation) for high status position including winning a male-male competition. The aim of this study was to test the adequacy of measuring jealousy reaction in adolescent boys by way of changes in salivary testosterone level and finding their associations with some individual characteristics mentioned by researchers. For the purpose of measuring basal testosterone level and changes in this hormone level during the competition for a mate which simulated the internet mating and changes in this hormone after being informed of their failure in this competition, the boys who participated in our study provided three salivary samples. For finding associations of basal testosterone level and these hormonal changes with some individual characteristics, the boys filled in a set of questionnaires (EATQ-R, the short version of IPIP, EBIS, ISJS, RSPQ, Rosenberg Self-esteem Scale and expanded...
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Mechanisms of relationship between melanin-based colouration and behavioural syndromes in birds
Nacházelová, Martina ; Javůrková, Veronika (advisor) ; Tomášek, Oldřich (referee)
Melanins are the most common pigments incorporated into birds' feathers. Since melanin-based coloration is variable in the extent and intensity, its function is considered to be particularly cryptic and mechanical, hardening the feather structure. However, recently it has been found that melanin- based coloration also has a signaling function, due to the observed correlation between this type of coloration and many physiological and behavioral traits. These relationships follow from the pleiotropic effects of genes regulating the melanocortin system and the physiological effects of testosterone and corticosterone, which are involved in melanogenesis. This work describes genetic and physiological mechanisms of the relationship between melanin-based coloration and behavioral traits in birds and, based on available studies, supports the signaling function of this type of coloration. Melanin-based coloration has been shown to be positively correlated with aggressiveness and dominance, sexual activity, coping with stress, a fast strategy of exploratory behavior, parental care, and anti-predator behavior in many bird species. However, despite intense research interest in this topic in last decade, it is worth noting that more experiments focused on species with a distinct sexual dichromatism or...
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Biological and related theories of aggression and its humoral regulation
Bradáč, Ondřej ; Komárek, Stanislav (advisor) ; Havlíček, Jan (referee)
Aggression is a phenomenon which acquired a substantial share on attention of biological literature, especially since the beginning of 20th century. In this thesis, various approaches to the problem from the field of biology are summarized. Intensified attention is dedicated to the theoretical concepts of aggression, especially the concepts consulting the problem of aggression from the evolutionary point of view and to the research on the field of hormonal regulation of aggression, stressing out the role of the hormone testosterone, and to particular hypothesis, which take account on its mutual relationship with behavior. The empirical part of the thesis is dedicated to verification of premises of the challenge hypothesis according to the relationship between testosterone and aggressive behavior. Significant findings of the empirical part refer to the existence of a link between basal level of testosterone and aggressive tendencies and to the existence of a negative link between basal level of testosterone and its increase in reaction to a competitive situation.
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