Ips perturbatus, frons
Ips perturbatus, declivity
Ips perturbatus, lateral habitus
Ips perturbatus, declivity
Ips perturbatus, declivity, spine 3 (petiolate)
Ips perturbatus, declivity, spine 3 (non-petiolate)

Scientific Name

Ips perturbatus (Eichhoff, 1869)

Synonyms

Tomicus hudsonicus LeConte, 1876

Tomicus interpunctus Eichhoff, 1878

Diagnostic notes

-Has four spines on each side of the elytral declivity. 
-Frons lacks a central tubercle and has a pair of circular tubercles on either side of the midline. 
-Third declivital spine is acute, and petiolate or nearly parallel-sided with tapered apex; interstriae of elytral disc lack punctures. 
-Potentially sympatric with related species I. tridens, I. pilifrons, I. borealis, and morphologically similar species I. pini (some females of I. pini are similar). 
-It differs from the related species by the nearly impunctate discal interstriae and from I. pini by a tranverse pair of tubercles on the frons.

Morphological Summary

sexes combined
Body. 4.0-4.7(-5.7) mm long, 2.3-2.5 times longer than wide; pronotum 1-1.1 times longer than wide.
Head. Epistomal margin with uniseriate row of tubercles with gap at midline. Frons outline convex in lateral view; vestiture fine (not hiding part of integument); surface sculpture near epistoma densely tuberculate-punctate or with isolated tubercles; central carina present or absent; central tubercle absent; transverse carina absent or present; frons central fovea present or absent; circular tubercles above top of eyes present - up to, or more than one third of all tubercles. Vertex and pronotum without stridulatory apparatus (pars stridens). Antennal club sutures bisinuate.
Prothorax. Protibiae with three or four socketed teeth on apical half (does not include apical spine).
Elytra. Interstriae impunctate or punctate (observed on interstriae 2 and 3 on middle third of elytral disc), punctures (0.4-)0.5(-0.6) times diameter of adjacent strial punctures (punctures and striae measured at steepest part of puncture wall), interstrial setae longer than width of scutellar shield, interstriae (4-)5(-6) times as wide as adjacent striae. Elytral declivity with four spines per side, spine 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 straight sided with tapered apex or pedunculate (capitate), apex acute, with apical half symmetrical or asymmetrical in lateral view; spines 2 and 3 on shared tumescence, in line with spines 1 and 4 (posterodorsal view); declivital integument shiny.

Geographic Distribution

Canada (Alberta, British Columbia, Manitoba, New Brunswick, Northwest Territories, Ontario, Quebec, Saskatchewan, Yukon); USA (Alaska, Colorado, Maine, Michigan, Minnesota, Montana, Washington).

Hosts

Picea spp.

Notes

I. hunteri, and I. perturbatus form clade (Cognato and Sun 2007).

References

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.

Cognato, A.I. and Sun, J.H. 2007. DNA based cladograms augment the discovery of a new Ips species from China (Coleoptera: Curculionidae: Scolytinae). Cladistics, 23: 539–551.

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

https://www.barkbeetles.info/regional_chklist_target_species.php?lookUp=1720