POPULATION-DYNAMICS AND PREDATOR-PREY-INT ERACTION BETWEEN THE PREDATOR NEMOSOMA-ELONGATUM AND THE BARK BEETLE SPECIES PITYOGENES-CHALCOGRAPHUS (COLEOPTERA, OSTOMIDAE, SCOLYTIDAE)

Population-dynamics of the predator Nemosoma elongatum Linnaeus 1758 a nd of the bark beetle Pityogenes chalcographus Linnaeus 1758 were inve stigated with pheromone traps in different conifer-stands in 1991-1993 . The proportion of predators in traps baited with Chalcoprax varies c onsiderably between 1991 and 1993 with a local maximum of 20%. The pop ulation of Nemosoma elongatum increases earlier in spring than that of Pityogenes chalcographus, so reduction of the bark beetle population by predation may therefore be relatively high in V and VI.