In the present dissertation the possibilities of aggregation of antagonists of bark beetles using allochthonous kairomones were to be analysed. The focus of the analysis was the species of European red-bellied clerids (Thanasimus spp.) in forests of Scots pine (Pinus sylvestris) and common spruce (Picea abies). Differences in trap efficiency have been analysed using the normal THEYSOHN® - slit trap and those with closed lids filled with a catching liquid. It transpired that significantly more target organisms have been locked in with the closed trap system than with the customary model. As potential attractants for European red-bellied clerids (Thanasimus spp.) standard attractants such as Pheroprax®, Sexowit®, Cembräwit®, Acuwit®, Tomowit® as well as Chalcoprax® have been tested. Furthermore the aggregate effect of individual semiochemicals, which form part of the above attractants, have been analysed in relation to European red-bellied clerids and bark beetles which appeared in the habitat. The effect of an increase of the emission rate of the attractant onto the target organisms was also part of the analysis. In addition to trials with attractants in THEYSOHN®-slit traps trials with attractants on stems of pine wood and spruce wood have also been conducted and analysed. This was to clarify whether one could aggregate that many antagonists of bark beetles that the stem does not at all or gets less populated with bark beetles. In the course of this analysis it has been attempted to identify further antagonists of bark beetles that could be aggregated with attractants. It was determined that there are important differences in levels of aggregation between the species of Thanasimus formicarius, Thanasimus rufipes and Thanasimus pectoralis with respect to the substances tested. Thanasimus formicarius has been observed in spring and early summer in pine and spruce forests. The concentration of activity of this species was higher in pine forests than in spruce forests. With respect to the tested attractants Thanasimus formicarius showed a stronger preference for Ipsdienol and Ipsenol as for (S)-cis-Verbenol in each case in connection with 2-3-2-Methylbutenol. It is also possible to replace 2-3-2-Methylbutenol with other substances. The substances of Sexowit® and Acuwit® ((+)-Ipsdienol, (-)-Ipsenol, α- and β-Pinen, 2-Phenylethanol or rather Ethanol) also seem to have a strong attraction for the Thanasimus formicarius. Thanasimus rufipes and Thanasimus pectoralis mainly appeared from early summer into the late summer and were respectively recorded in the traps. Both species, in comparison to the Thanasimus formicarius, showed a much stronger preference to (S)-cis- Verbenol, respectively attractant mixtures which contained (S)-cis-Verbenol. Thanasimus rufipes has mainly been detected in pine forests and Thanasimus pectoralis in spruce forests. In pine forests Pheroprax® could be confirmed as an effective allochthonous kairomone. In spruce forests, until the completion of this analysis, no definitive attractant could be identified which aggregats European red-bellied clerids (Thanasimus spp.) on the object to be protected without attracting bark beetles (namely Ips typographus).

Naturnahe Verfahren im Management bast- und holzbesiedelnder Insekten basieren auf der Ausnutzung olfaktorischer Reaktionen dieser Insekten und teilweise auch derer Antagonisten auf Semiochemikalien käferbürtigen und baumbürtigen Ursprungs. Verfahren, die im Rahmen der Forschungsarbeit verfolgt wurden, waren zum überwiegenden Teil das Wirkungsprinzip Allochthoner Kairomone sowie Abwehrverfahren bei denen Nichts-Wirtsbaum-Volatile zum Einsatz kommen. Als biologischer Detektor von zu identifizierenden Semiochemikalien aus Laubwaldhabitaten wurde der Ameisenbuntkäfer Thanasimus formicarius verwendet. Von T. formicarius ist eine stark generalistische Lebensweise bekannt, die zur Annahme verleitet, dass dieser auch als Prädator an diversen Laubholz besiedelnden Borkenkäferarten auftritt. Entsprechend wurden als Beuteobjekte in Laubwaldhabitaten die Arten Trypodendron domesticum, Trypodendron signatum, Leperisinus varius und Scolytus intricatus vermutet und schwerpunktartig untersucht. Mittels GC-MS/EAD-Analysen konnte nachgewiesen werden, dass T. formicarius Substanzen aus den Habitaten in Wäldern von Rot-Buche, Gemeiner Esche und Eiche wahrnehmen kann. Für einen Teil der von T. formicarius wahrgenommenen Substanzen wurden Dosis-Antwort-Kurven aufgenommen, um Erkenntnisse über die Wahrnehmungsschwelle bei T. formicarius zu erhalten und eine mögliche Bedeutungen der Substanzen in der olfaktorischen Orientierung im Laubwaldhabitat abzuleiten. Die Ergebnisse verdeutlichten, dass T. formicarius neben käferbürtigen Substanzen auch eine Vielzahl von pflanzenbürtigen Volatilen wahrnehmen kann. Dabei wurden für einige dieser Substanzen sehr geringe Wahrnehmungsschwellen festgestellt, was eine besondere Bedeutung der Substanzen in der olfaktorischen Orientierung von T. formicarius vermuten lässt. Substanzen, von welchen eine signifikante Wahrnehmung von T. formicarius erfasst werden konnte, wurden in Olfaktometerexperimenten auf verhaltensmodifizierende Wirkungen beim Ameisenbuntkäfer untersucht. Die in Laborexperimenten auf Wahrnehmung von T. formicarius getesteten Substanzen wurden letztlich in Fallenfangexperimente und Fangholzexperimente eingebunden. Ein Anflug von T. formicarius auf die in den Laborexperimenten erprobten Substanzen, konnte in Fallenfangexperimenten im Freiland, bei der Verwendung der zu erprobenden Substanzen als Einzelsubstanzen, kaum beobachtet werden. Auch die Kombination der Einzelsubstanzen zu Mixturen erzeugte keine nennenswerten Attraktivitäten auf T. formicarius und andere Prädatoren im Freiland. Dennoch schienen die Substanzen aufgrund ihrer teilweise repellenten Wirkung auf bast- und holzbesiedelnde Insekten geeignet, um zumindest in naturnahen Managementverfahren eingesetzt zu werden. Den Ergebnissen der Fallenfang- und Fangholzexperimente entsprechend können die aus dem Nadelwaldhabitat stammenden Pheromondispenser Sexowit® und Chalcogran als Allochthone Kairomone im Laubwaldhabitat empfohlen werden. Darüber hinaus scheint eine Applikation von exo-Brevicomin und endo-Brevicomin als Allochthone Kairomone im Nadelwaldhabitat denkbar, muss jedoch noch am Fangholz geprüft werden. Aus den Fallenfangexperimenten konnten zudem Substanzen abgeleitet werden, welche sich im Monitoring von bast- und holzbesiedelnden Insekten aus Laub- und Nadelwaldhabitaten eignen. / Nature-based methods in the regulation of bark and wood boring insects are based upon the use of olfactory responses of these insects and also partly of their antagonists to semiochemicals that originate from bark and wood boring insects or their host plants. Methods used during this research were the Allochthonous Kairomones principle and defense methods with non-host volatiles. Thanasimus formicarius was used as biological detector for identifying semiochemicals from deciduous forest habitats. T. formicarius is known to be a highly generalist predator, which led to the assumption that T. formicarius may occur as predator of various bark and wood boring insects living on deciduous tree species. Accordingly, Trypodendron domesticum, Trypodendron signatum, Leperisinus varius and Scolytus intricatus were assumed to be prey species in deciduous forest habitats and hence focused on in this study. A GC-MS/EAD analysis demonstrated that T. formicarius is able to perceive substances from the habitats of European beech, common ash and oak. For some of the perceived substances dose-response-curves were recorded to obtain knowledge about the perception threshold of T. formicarius and to derive the potential importance of the substances in the olfactory orientation in deciduous forest habitats. The results show that T. formicarius is able to recognize a variety of plant-derived volatiles as well as substances from bark and wood boring insects. For some of these substances very low perception thresholds were determined, suggesting a particular importance of these substances in the olfactory orientation of T. formicarius. Substances that were found to be significantly perceived by T. formicarius were further examined in olfactometer experiments in order to test for behavior-modifying effects. Substances that were tested for perception by T. formicarius in the laboratory experiments were finally included in trapping experiments and trap log experiments. When used as single compounds, low numbers of T. formicarius were attracted to substances used in trapping experiments. Also the combination of single substances to mixtures produced no significant attractions of T. formicarius and other predators in trapping experiments. However, some of the substances seemed to be appropriate for using in nature-based management methods because of repellent effects to bark and wood boring insects. According to the results of trapping and trap log experiments, pheromone dispensers such as Sexowit® and chalcogran from coniferous forest habitats can be recommended as Allochthonous Kairomones in deciduous forest habitats. In addition, an application of exo- and endo-brevicomin as Allochthonous Kairomones in coniferous forest habitats seems possible, but still has to be tested with trap log experiments. In addition within these experiments substances were detected that can be used in the monitoring of bark and wood boring insects in coniferous and deciduous forest habitats.