J. Weslien 1992: The arthropod complex associated with Ips typographus (L) (Coleoptera, Scolytidae), species composition, phenology, and impact on bark beetle productivity. - Entomologica Fennica 3: 205-213.
The biology of forest arthropods associated with the bark beetle Ips typographus and the impact of these associates on bark beetle productivity were investigated in the field. Arthropods were allowed access to spruce bolts for different lengths of time, 0, 1, 4, and 8 weeks, following onset of attack by Ips typographus, after which time the bolts were moved to a nonforested area and caged. Arthropods were collected as they emerged from the bolts in autumn and the following spring. At least 32 arthropod species were collected, of which 17 are known to feed on bark beetle brood. The longer the exposure period the more bark beetle enemies and the fewer Ips typographus emerged. Natural enemies were estimated to have reduced bark beetle productivity by 83%. Arrival and emergence patterns and relative impact on bark beetle productivity of different species are discussed.