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Scaling of spatial activity in bats
Křemenová, Jana ; Lučan, Radek (advisor) ; Storch, David (referee)
2 ABSTRACT The degree of spatial activity, especially the home-range size, is one of the basic biolog- ical characteristics of animals and whether it has enough resources is crucial for the survival and reproduction of the individual. Therefore, it is not surprising that many studies trying to make clear the effect of various ecological and morphological variables and explain the varia- bility of space activities. Bats are a group of mammals, for which until recently, existed only few information about their spatial activity. However, due to the miniaturization of technology and the use of radiotelemetry amount of information rapidly increasing. The aim of this study was to assemble the most complete information about the home- range size and foraging distance of bats and analyze the effect of variables that can influence the spatial activity. From published papers I collected data on 106 species representing 8 fami- lies. The influence of 6 variables (weight, wing loading, aspect ratio, food specialization, colony size, primary productivity of environment) on home-range size and average foraging distance of bat was analysed by phylogenetic regression (PGLS). The best predictor of the home-range size is the primary productivity of the environment, food specialization and body size. The best explanation of...
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Evolution of brain size in bats (Chiroptera)
Králová, Zuzana ; Němec, Pavel (advisor) ; Kratochvíl, Lukáš (referee)
According to the prevailing doctrine, brain size has mainly increased throughout the evolution of mammals and reductions in brain size were rare. On the other hand, energetic costs of developing and maintaining big brain are high, so brain size reduction should occur every time when the respective selective pressure is present. Modern phylogenetic methods make it possible to test the presence of evolutionary trend and to infer the ancestral values of the trait in question based on knowledge of phylogeny and trait values for recent species. However, this approach has been rarely applied to study brain evolution so far. In this thesis, I focus on bats (Chiroptera). Bats are a suitable group for demonstrating the importance of brain size reductions. Considering their energetically demanding mode of locomotion, they are likely to have been under selection pressure for brain reduction. Furthermore, there is a large amount of data on body and brain mass of recent species available. Finally, phylogenetic relationships among bats are relatively well resolved. My present study is based on body masses and brain masses of 334 recent bat species (Baron et al., 1996) and on a phylogeny obtained by adjusting existing bat supertree (Jones et al., 2002) according to recent molecular studies. Analysing the data for...
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