Ips emarginatus, male frons
Ips emarginatus, female frons
Ips emarginatus, male declivity showing emarginate spine 3
Ips emarginatus, male declivity
Ips emarginatus, female declivity
Ips emarginatus, declivity, spine 3
Ips emarginatus, male lateral habitus
Ips emarginatus, female lateral habitus

Scientific Name

Ips emarginatus (LeConte, 1876)

Diagnostic notes

-Has three spines on the elytral declivity.
-Differs from other Ips by its large size (5.5–7.0 mm) and emarginate spine 3.
-sister species to I. knausi, which is diagnosable from emarginatus by the absence of elytral interstrial punctures and the presence of a fourth declivital spine.

Morphological Summary

females
Body. 5.5-7.0 mm long, 2.7-2.8 times longer than wide; pronotum 1.1-1.2 times longer than wide.
Head. Epistomal margin with uniseriate row of tubercles with elongate mesal tubercle. 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, without pair of circular tubercles on either side of midline; transverse carina present, punctate; frons central fovea present or absent; circular tubercles above top of eyes present - up to one third of all tubercles. Vertex and pronotum without stridulatory apparatus (pars stridens). Antennal club sutures bisinuate.
Prothorax. Protibiae with four 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), interstriae 2-3 times as wide as adjacent striae. Elytral declivity with three spines per side, spine 3 largest; spine 1 (largest on 2nd interstria) closer to spine 2 than suture; spines 1 and 2 separated at base by distance less or greater than height of spine 1; spine 2 closer to spine 1 than spine 3 or 3 than spine 1; spine 3 emarginate, apex right-angled or obtuse to rounded, with apical half symmetrical or asymmetrical in lateral view; spines 2 and 3 not on shared tumescence; declivital integument mat.

males
Body. 5.5-7.0 mm long, 2.7-2.8 times longer than wide; pronotum 1.1-1.2 times longer than wide.
Head. Epistomal margin with uniseriate row of tubercles 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 present and single, separated from base of epistomal setae by 0-0.5 tubercle diameters, without pair of circular tubercles on either side of midline; transverse carina present, punctate; frons central fovea present or absent; circular tubercles above top of eyes present - up to 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 (observed on interstriae 2 and 3 on middle third of elytral disc), interstriae 2-3 times as wide as adjacent striae. Elytral declivity with three spines per side, spine 3 largest; spine 1 (largest on 2nd interstria) closer to spine 2 than suture; spines 1 and 2 separated at base by distance less or greater than height of spine 1; spine 2 closer to spine 1 than spine 3 or 3 than spine 1; spine 3 emarginate, apex right-angled or obtuse to rounded, with apical half asymmetrical in lateral view; spines 2 and 3 not on shared tumescence; declivital integument mat.

Geographic Distribution

Canada (British Columbia); Mexico (Baja California); USA (California, Idaho, Montana, Oregon, Washington)

Hosts

Pinus spp. Known from P. jeffreyi, P. monticola, P. ponderosa.

Notes

Clade formed by ((I. emarginatus + I. knausi) + I. sexdentatus), see 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=1707