Ips spp. (Scolytidae)
Twenty-five species of Ips are recognized in the west.
Reddish-brown to black, often shiny, cylindrical bark beetles ranging in size from 3 to 6.5 mm. A distinguishing feature of the genus is the pronounced concavity at the rear end of the elytra of the adult, which is marginated on each side with 3 to 6 tooth-like spines.
Typical scolytid larvae, brown head capsule, white body, apodous (no appendages i.e. no legs or other type of limbs)
Different species of Ips, like Dendroctonus, are host specific to various species of conifers. Many species infest the upper bole of trees leaving the lower bole to the larger bark beetles. They may also infest a tree without associate insects. Adults are polygamous one male pairing with several females. Gallery pattern is radiate with galleries free from frass. Larval mines radiate from along gallery walls. Note the scoring of the sapwood which gives the beetles their name of engraver beetles. See examples of damage by Ips tridens (engelmanni).
Most species of pines and spruces have associated Ips species.
Among the western bark beetles, Ips spp. are second in destructiveness only to Dendroctonus spp.
References and Links:
EAG: 491-498, 508-512; FC: 383.