The Influence of Four Different Predators on Bark Beetles in European Forest Ecosystems (Coleoptera: Scolytidae)

Abstract

Field and laboratory work was carried out to study the possible impact of 4 different species of bark beetle enemies. These are Scoloposcelis pulchella Zetterstedt 1838 [Heteroptera: Anthocor -idae], Thanasimus formicarius Linnaeus 1758 [Coleoptera: Cleridae] Nemosoma elongatum Linnaeus 1761 [Coleoptera: Ostomidae] and Medetera dendrobaena Kowarz 1877 [Diptera: Do-lichopodidae]. These species are preying upon many bark beetles. The main prey species of N elongatum and Mdendrobaena are Pityogenes chalcographus Linnaeus 1758 [Coleoptera: Scolytidae] and Taphrorychus bicolor Herbst 1793 [Coleoptera: Scolytidae], S pulchella mainly attacks P chalcographus. On spruce the bark beetle Ips typographus Linnaeus 1758 [Coleoptera: Scolytidae] is one of the most important prey species of T formicarius. The predator and the bark beetle species were reared in the laboratory to gain information about their biology. The Scolytidae were also reared to provide an adequate food supply for the predators. In the laboratory, the egg production of the predator species and the prey consumption during their larval development were determined. Furthermore, the densities and the voltinism of the antagonists and of the bark beetles were investigated. Calculations to estimate the predator capacity of the 4 antagonistic species were performed. Based on this data the role of S pulchella, T formicarius, N elongatum and N dendrobaena in bark beetle regulation is discussed.