This thesis deals with thermoregulation in red wood ants, in Formica rufa group. Our aim was to better understand the mechanisms by which red wood ants maintain thermal homeostasis in their nests. Red wood ants are known to keep high and stable temperatures in their nests from spring to autumn. Most emphasis is placed on the role of the nest mound as a solar collector or on a heat production by microbial community present in the nest material. However, some researchers believe that wood ants are able of active nest thermoregulation in which they can affect the nest temperature by behavioural reactions, mainly by sun basking, increased metabolic heat production or heat transport. The thesis consists of three research articles. The first one is focused on the timing of thermoregulation in red wood ants, the second one investigates in more detail one specific aspect of red wood ant thermoregulation - a sun basking behaviour. These two papers provide data from long-term field observations and experiments. The last paper is based on laboratory experiments where we tested a hypothesis resulting from field observations. Thanks to the field research we found out that ant activity (traffic on ant trails) significantly correlates with nest temperature; once the activity decreased the thermal homeostasis...

The thesis is concerned with methodological specifics of beginner piano teaching of students at different age levels. It attempts to give a complex view of its various aspects. The thesis is subdivided into several chapters, drawing on available psychological and methodological literature, piano course books and a questionnaire survey. The first chapter focuses on a beginner piano learner as an individual undergoing a particular stage of psychological development. It explores learners' general as well as music- specific characteristics and links these characteristics to piano playing. In addition, it describes motivational tendencies prevailing at different development stages, and other factors which can substantially influence the learning process, but have not hitherto been discussed with respect to piano teaching in greater detail although a pedagogue can more easily deal with potential problems that may arise at beginner levels when thoroughly informed. It namely discusses learning and teaching styles, hindrances to learning and learning disabilities. The second chapter is devoted to methodological specifics of teaching learners of different age groups. The third chapter then expands on the subject of beginner piano teaching specifics, comparing techniques used in beginner piano books aimed at various...

Sexual ornaments important for mating success in many species are often assumed to evolve as condition-dependent signals of individual quality. Ornament expression can be associated with age and survival, thereby signalling individual viability. Here, we have tested viability signalling function of tail streamers and their importance for within-pair and extra-pair fertilisation success in the European barn swallow (Hirundo rustica rustica). In contrast to previous studies on this subspecies, our data suggest that tail length is not associated with fertilisation success in our population. Instead, the most important predictors of within-pair and extra-pair fertilisation success were female and male age, respectively. Our data supported viability signalling function of male tail streamers, as documented by age-related within- individual increase in their length. There was no evidence for senescence in this trait. Contrary to some previous studies, the viability signalling function of tail streamers was further supported by observed selective disappearance of males with shorter tails. Several physiological mechanisms have been proposed as maintaining signalling honesty. Among them, oxidative stress from highly reactive species (RS), including free radicals, attracted a considerable attention. Given...