Observations on the bionomics of Crypturgus species

Crypturgus bark beetles are only mentioned sporadically in the literature and their significance as the potential predator of developmental stages of other bark beetles is underestimated. An extraordinarily high capture on insecticide-treated trap tipi assembled from three and five timber sections in the form of a pyramid allowed one to determine the interaction of Ips typographus flight activity and temperature. The beginning and culmination of the flight activity of Crypturgus species are characterised by mean daily temperatures above 11.8 °C and 14.7 °C, respectively. From the beginning until the culmination of the swarming, more specimens of Crypturgus cinereus (86%) were captured than of Crypturgus pusillus (68%) whose occurrence was extended until mid-August. Only a single generation was demonstrated during the growing period. On a bark beetle infested spruce was disturbed development of Ips typographus, because a high density of mother galleries of Crypturgus adults was recorded in its galleries.