Universiẗat, Diss., 2003--Bremen.

Univ., Diss.--Münster, 1996.

- 4 - ABSTRACT During the revision of epiphytic species of the Lecanora subfusca group in the Czech Republic, nine taxa have been recorded. L. cinereofusca and L. exspersa are reported for the first time from the country. L. circumborealis has been excluded from the list of Czech lichens. L. cinereofusca and L. horiza could be considered as extinct. L. rugosella and L. subrugosa are regarded as extreme morpholocial forms from L. chlarotera and L. argentata. These morphotypes corelate with ecological conditions: substrate (nutrient enriched bark) and habitat (eutrophisation effect). In case of L. subrugosa, this speculation was confirmed by molecular data (ITS rDNA sequences). Several new secondary metabolites have been discovered during the detailed research of chemical lichen compounds. These substances belonging to terpenoids are taxonomically important and very helpful for distinguishing single species. The abundance of L. allophana and L. chlarotera has decreased during last decades. Contrarily, L. pulicaris expanded slightly. The main reasons of changes in distribution are air pollution and acidification of substrates as the impact of acid rains. The rate of substrate acidification has been shown on example of L. pulicaris. In the past, this lichen predominated on acid-barked porophytes. Nowadays, it...

Ceratitis fasciventris, Ceratitis anonae and Ceratitis rosa are polyphagous agricultural pests originating from African continent. Their behaviour is heavily altered by pheromones. Insect chemical communication channels are species-specific, represents taxonomic and reproduction barriers. Taxonomy of this group (so-called Ceratitis FAR complex) is unclear. Therefore new chemical approaches along with genetic tests for identification of entities within the cryptic species FAR complex are being developed. To study multi-component mixtures of male volatiles originating from the three mentioned fruit fly species, comprehensive two-dimensional gas chromatography with time- of-flight mass spectrometer (GC×GC-TOFMS) was used. A number of compounds were identified, out of which 23 were found to be distributed and shared among the studied species, 11 out of these were present in all three species. Analyses of male pheromone volatiles, using gas chromatography combined with electroantennographic detector (GC-EAD) revealed 4 common compounds with antennal activity shared among three studied species: methyl (E)-hex-3-enoate, 6-methylhept-5-en-2- one, linalool, and methyl (2E,6E)-farnesoate. The species-specific EAD active compounds in C. fasciventris were esters of isomers of hexenoic acid, whereas isomers of...