Parazitacia zimujucich lariev podkornika duboveho (Scolytus intricatus Ratz.) parazitoidmi

Parasitation of overwintering larvae of the European oak bark beetle (Scolytus intricatus Ratz.) by parasitoids

Zvolen

2003

4 Abb., 12 Lit. Ang.

Artikel aus einer Zeitschrift

7409

200111441

The purpose of the paper was to investigate the species composition and dominance of larval parasitoids of the European oak bark beetle (Scolytus intricatus) (Col., Scolytidae) in winter, as well as to estimate parasitation rates in depence upon the host density and the thickness of material. Altogether 50 samples of oak branches and trunks with a thickness of 1-16 cm were analysed. There were found 3 species of braconids (Hym. Braconidae) and 3 species of chalcidoid wasps (Hym., Chalcidoidea). the chalcidoid wasp Entedon leucogramma (Hym., Entedontidae) was present in 78 % of samples and constituted 87,1 % of emerged imagoes of parasitoids. Mean parasitation rate of larvae was estimated to be 18,4 - 24,8 %. Samples with a mean parasitation rate of 0,1-10,0 % highly predominated. A number of parasitised larvae increased with increasing population density of larvae but percentage of parasitised larvae was decreasing. Mean parasitation rate was statistically signficantly highest in samples with low population density of larvae (lessthan 250 larvae/m2) and with a thickness of 1-3 cm and 3-6 cm, respectively (on average 67,4 % and 36,6 % respectively). Parasitation rates of other samples were considerably lower (on average 3,6-8,1 %).