Canadian Journal of Arthropod Identification
Dichotomous and matrix-based keys to the Ips bark beetles of the World (Coleoptera: Curculionidae: Scolytinae)
CJAI 38 -- June 27, 2019
Hume B. Douglas, Anthony I. Cognato, Vasily Grebennikov, and Karine Savard
| Abstract | Introduction | Methods | Checklist | Results & LUCID Key | Glossary | Dichotomous Key | Acknowledgments | References | PDF | Cite |
| Supplementary Data |
Print Fact SheetIps avulsus

Scientific Name

Ips avulsus (Eichhoff, 1868)

Diagnostic notes

-Has four spines on the elytral declivity and general appearance is similar to I. pini (length 3.3–4.3 mm).
-Potentially sympatric in northern areas with similar I. pini. Differs by the always non-petiolate spine 3 of the male declivity, the shorter expansion of the declivital  apex, and the smaller size, 2.1–2.8 mm (Wood 1982)

Morphological Summary

sexes combined
Body. 2.1-2.8 mm long, 2.5-2.7 times longer than wide; pronotum 1.1-1.2 times longer than wide.
Head. Epistomal margin with uniseriate row of tubercles uninterrupted medially, with elongate mesal tubercle or with gap at midline. Frons outline convex in lateral view; vestiture  fine (not hiding part of integument); surface sculpture near epistoma densely tuberculate-punctate; central carina present or absent; central tubercle absent or present and single, separated from base of epistomal setae by 2-4(-5) tubercle diameters, without pair of circular tubercles on either side of midline; transverse carina absent or present; frons central fovea absent; circular tubercles above top of eyes absent or present - up to one third of all tubercles. Vertex and pronotum with or without stridulatory apparatus (pars stridens). Antennal club sutures bisinuate.
Prothorax. Protibiae with three socketed teeth on apical half (does not include apical spine).
Elytra. Interstriae impunctate (observed on interstriae 2 and 3 on middle third of elytral disc), punctures 0.6-0.7 times diameter of adjacent strial punctures (punctures and striae measured at steepest part of puncture wall), interstrial setae shorter than width of scutellar shield, interstriae 1-2 times as wide as adjacent striae. Elytral declivity with four spines per side, spine 2 or 3 largest; spine 1 (largest on 2nd interstria) closer to suture than spine 2; spines 1 and 2 separated at base by distance greater than height of spine 1; spine 2 closer to spine 3 than spine 1; spine 3 tapered, apex right-angled or obtuse to rounded, with apical half symmetrical in lateral view; spines 2 and 3 on or not on shared tumescence, not in line with spines 1 and 4 (posterodorsal view); declivital integument shiny.

Geographic Distribution

USA (Alabama, Arkansas, Florida, Georgia, Louisiana, Maryland, Mississippi, New Jersey, North Carolina, Oklahoma, Pennsylvania, South Carolina, Texas, Virginia, West Virginia).


Pinus spp.


Cognato, A.I.2015. Biology, systematics, and evolution of Ips. In Bark beetles: biology and ecology of native and invasive species. Edited by F.E. Vega and R.W. Hofstetter. Elsevier, San Diego, California. Pp. 351–370.

Wood, S.L. 1982. The bark and ambrosia beetles of North and Central America (Coleoptera: Scolytidae), a taxonomic monograph. Great Basin Naturalist Memoirs, 6: 1–1359.

Internet resources