Ips typographus L., European Spruce Bark Beetle Screening Aid

From: Cavey, J., Passoa, S. and Kucera D. 1994, Screening Aids for Exotic Bark Beetles in the Northeastern United States. NA-TP-11-94. Northeastern Area: U.S. Department of Agriculture, Forest Service.

General Appearance in a Sample. This moderate to large (4.2-5.5 mm), cylindrical, brown bark beetle has an excavated elytral declivity armed laterally with 4 spines on each side. The pronotum is covered with asperites on the anterior half. Viewed from above, erect yellow hairs protrude from the body perimeter and margins of the declivity.

Recognizing the Genus. In general, Ips differs from other North American scolytids in having the following combination of characters (from Wood 1982):

• Elytral declivity widely excavated, armed laterally with 3 or more teeth, the teeth arising from the summit (ridge) of the lateral margins.
• Pronotum asperate on the anterior half.
• Antennal funicle 5-segmented.
• Antennal club strongly flattened, with two sutures on the anterior face bisinuate or procurved (curved forward).

Recognizing I. typographus. Whittle and Anderson (1985) gives adult characters and illustrates this species. Color and SEM photographs of I. typographus are available in the Forest Service Pest Alert (Cavey and Passoa 1993). Superficially, this species might be confused with other Ips having 4 teeth on the elytral declivity. It is most like the I. plastographus group (Whittle and Anderson 1985), but none in that group are known to occur in the NER (Wood 1982).

In the northeastern U.S., four Ips species have 4 declivital teeth: avulsus, perroti, perturbatus and pini. In traps baited with Ipslure, I. pini is especially common. The European spruce bark beetle may be separated from the above four species using the following key.

Key to Help Screen Ips typographus from Ips spp. with Four Declivital Teeth
Known to Occur in the Northeastern U.S.:

The declivity may have to be cleaned of debris, oil, etc. to interpret its sheen.

1.	Frons with a median, transverse pair of tubercles distinctly larger than others (Fig. 1); declivity shining between punctures1 (I. perturbatus)	Not typographus
	Frons with a single, prominent, median  tubercle (Fig. 2); declivital sheen variable	See #2	Figure 1. Head of Ips perturbatus with 2 enlarged tubercles on frons (After Wood 1982).
2.	Spine 3 on declivity conical, not capitate  (Fig. 3), (avulsus 2.1-2.8 mm,  perroti 2.7-3.5 mm, and female pini)	Not typographus
	Spine 3 on declivity capitate  (see PA Fig. 4 for example)	See #3	Figure 2. Head of Ips spp. with single enlarged tubercle on frons (After Wood 1982)
3.	Declivity shining between punctures  (see PA Fig. 5 forexample)1; usually  smaller 3.3-4.3 mm (pini males)	Not typographus
	Declivity dull (shagreened) between punctures (see PA Fig.5 for example)1; usually larger 4.2-5.5 mm	Ips typographus suspect	Figure 3. Apex of elytra of Ips avulsus, showing conical 3rd tooth (After Wood 1982).

adult beetle
Photo by Steve Passoa

[ Back ]