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).
| Identifer | oai:union.ndltd.org:DRESDEN/oai:qucosa.de:bsz:14-qucosa-130475 |
| Date | 06 February 2014 |
| Creators | Hellmund, Matthias |
| Contributors | Technische Universität Dresden, Fakultät Umweltwissenschaften, Prof. Dr. Michael Müller, Prof. Dr. Mechthild Roth |
| Publisher | Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden |
| Source Sets | Hochschulschriftenserver (HSSS) der SLUB Dresden |
| Language | deu |
| Detected Language | English |
| Type | doc-type:doctoralThesis |
| Format | application/pdf, application/pdf, application/zip |
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