How to Identify Common Insect Associates of the Southern Pine Beetle

How to Identify Common Insect Associates
of the Southern Pine Beetle

Southern Pine Beetle Handbook

United States Department of Agriculture, Combined Forest Pest Research and Development Program, Southern Pine Beetle Handbook, Agriculture Handbook No. 563. 1980.

Coleoptera Histeridae Histeridae: The histerids are black, shiny, hard-bodied beetles with short elytra. The posterior abdominal segments are exposed dorsally beyond the elytra. Platysoma (Cylistix) cylindrica (Paykull) (figs. 4A, 5): P. cylindrica (4.3 mm) has a spiny front tibia and a pointed prosternum (fig. 4A). P. (Cylistix) attenuata (LeConte) (figs. 4a, 6): P. attenuata is similar to P. cylindrica but is smaller (3.1 mm) than P. cylindrica. Also, P. attenuata appears thinner when viewed dorsally (fig 6).
	Figure 4A

	Figure 4B

Figure 5	Figure 6


Figure 7	Figure 8
P. parallelum Say (figs. 4B, 7): P. parallelum (2.7-3.6 mm) can be distinguished from these first two species because it has a rounded prosternum (fig. 4B). In addition, its pronotum is short relative to the length of the elytra (fig. 7), and it lacks deep pits on the metasternal plate. Plegaderus Erichson (fig. 8): Plegaderus is a tiny (1.5 mm), oval, shiny, black beetle. Plegaderus has short elytra and is punctate with a smooth band on the prothorax.

Trogositidae

Trogositidae: Trogositids (formerly Ostomidae) have large heads and pronota and a narrow union between the pronotum and elytra. They appear somewhat flattened dorsoventrally. Temnochila virescens (F.) (figs. 10, adult; 9, larva): This predator is large and elongate. Its size (20 mm) and its brilliant metallic green color make it easily recognizable. Larvae are white, have dark heads, well-developed thoracic legs, and two darkened anal projections (urogomphi). They have fused thoracic shields on the second segment. Tenebroides collaris (Sturm) (fig. 11): T. collaris can be distinguished from T. marginatus (fig. 11) because it is larger (7.2 mm) and has dark brown to black elytra and a reddish brown head. Each species has a punctate head and margined elytra. T. marginatus (Palisot de Beauvois) (fig. 12): T. marginatus (5.2 mm) is more uniformly medium brown on the pronotum and elytra than T. collaris.
	Figure 9

	Figure 10

Figure 11	Figure 12

Staphylinidae

Nudobius luridipennis Casey (fig. 13): N. luridipennis (7.5-8.2 mm), like other staphylinids, are slender and elongate with very short elytra (usually only as long as the elytra are wide). The antennae are beadlike and medium length. It should be noted that there are other species of staphylinids associated with the SPB that, although quite common, are yet undescribed.

Figure 13

Cleridae Thanasimus dubius (F.) (figs. 14, 15, 16): The checkered beetle, T. dubius (7.5-9.0 mm), has easily distinguishable black elytra with white angulate crossbars. The head, thorax, and base of the elytra are red. The larvae are pink when alive (white if preserved), do not have fused thoracic shields, but are otherwise similar to T. virescens larvae (see fig. 10).
	Figure 14

Figure 15	Figure 16

Cucujidae

Silvanus bidentatus (F.) (fig. 17): Silvanus spp. (3.5-3.9 mm), like other cucujids, are extremely flat, densely punctate, amber brown, and have an elongate prothorax and head. The antennae are beadlike and medium length. There are two teeth on the front angle of the pronotum.

Figure 17

Colydiidae


Figure 18A	Figure 18B		Figure 18C

Figure 19		Figure 20
Aulonium Erichson (figs. 18, 19): Both species presented here are elongate, pale brown, and 3.5-5.0 mm long. They have relatively short, clubbed antennae. Aulonium spp. are separated from other SPB insect associates by the strong ridges running nearly the length of the pronotum. A. ferrugineum Zimmermann, has distinguishing projections on the anterior pronotum, which extend beyond the anterior corners (fig. 18A). A. tuberculatum LeConte males (fig. 18B) have distinct pronotal tubercles that are absent in the females (fig. 18C).		Figure 21
Colydium lineola Say (fig. 20): C. Lineola (3.5-5.5 mm) has a ridged pronotum, but the elytra are much more elongate and cylindrical than those of other colydiids found with the southern pine beetle. Lasconotus Erichson (fig. 21): Lasconotus spp. also have a ridged pronotum, but all are considerably smaller (2.8 mm) than Aulonium spp. They are reddish brown, with rough, striated elytra, and clubbed antennae.

Tenebrionidae

Figure 22	Figure 23
Corticeus Pillar and Mitterpacher (figs. 22, adult; 23, larva): Adult Corticeus spp. (3.0-3.4 mm) have an elongate, cylindrical shape, 11-segmented antennae, and amber-brown color (fig. 22). Larvae are laterally striped with alternating light and dark bands on the dorsum of each segment (fig. 23).

Curculionidae

Cossonus corticola Day (fig 24): The weevil most frequently encountered in association with SPB galleries is C. corticola (4.0-5.0 mm). When the insect is viewed laterally, the stubby snout is the most representative feature. The body is black, cylindrical, and elongate with a punctate and striated elytra. There is a deep groove between and above the eyes.

Figure 24

Cerambycidae

Cerambycidae: Cerambycids are the largest insect associates of the SPB. They characteristically have very long antennae, often longer than the body. All cerambycid larvae are cylindrical, fleshy white, and legless (fig. 25). They taper gradually from anterior to posterior, and are not C-shaped. They have darkened, strong, well-developed mandibles. Cerambycids taper less abruptly than buprestid larvae, and do not possess an inverted "V" on the large first segment as do the buprestids (fig. 26) Monochamus Serville (fig. 27): Monochamus spp., or pine sawyers, are 17.5-30.0 mm long as adults, and are mottled gray and brown. The thorax has a stout spine on either side. The male antennae are 2 l/2 times body length; female antennae are 1 1/2 times body length. Neacanthocinus obsoletus (Olivier) (fig. 28): N. obsoletus adults are smaller (7.0-14.0 mm) than other sawyers and have black patterns on a primarily gray elytra. The elytra is distinctly punctate nearly to the apex. Lateral tubercles are present on the pronotum, and the legs are successively longer from front to rear.
		Figure 25
		Figure 26

Figure 27	Figure 28

Platypodidae


Figure 29	Figure 30
Platypus flavicornis F. (figs. 29, male; 30, female): Males have two stout spines on the end of the elytra. Females lack the spines, but like the males, have a very elongate metathorax. Thus, the hind legs appear to rise from the abdomen. The abdomen is very short relative to overall body length. The tip of the elytra are squared off in the middle. Average length for each sex is 5.0 mm.

Scolytidae


Figure 31	Figure 32

Figure 33	Figure 34

Xyleborus Eichhoff (figs. 31, 32): Xyleborus spp. are small (2.0-3.0 mm) and oblong. When viewed from above, the prothorax conceals the head. Like Ips spp., some Xyleborus have irregular teeth or spines on the posterior of the elytra. These insects, however, have a more shallow declivity than Ips and no shelf at the base of the elytra (fig. 31). Xyleborus has a bellshaped pronotum that is wider than the anterior portion of the elytra.
Dendroctonus frontalis Zimmermann (fig. 33): D. frontalis, the SPB (2.2-4.0 mm), should be easily recognized by the users of this guide. The head is visible from above, with the elevation on either side of the medial frontal groove more pronounced in the male; the female has a ridge on the anterior margin of the pronotum.
D. terebrans (Olivier) (fig. 34): Its size (5.0-8.0 mm) makes the black turpentine beetle easily recognizable. It has club-shaped antennae and no declivity at the posterior of the elytra, with the pronotum widening posteriorly.


Figure 35	Figure 36
Ips De Geer: The pine engravers, or Ips spp., have spines lining a declivity on the posterior portion of the elytra. Unlike Xyleborus spp., the engravers have a distinct shelf, or ridge, at the base of the deep declivity. They are larger than other scolytids having a declivity lined with spines. I. avulsus (Eichhoff) (fig. 35): Elytral declivity is moderately excavated, with four teeth on each side; the second and third teeth are connected at their base. The apical margin is slightly elevated. Length is 2.1-2.8 mm.	Figure 37

I. grandicollis (Eichhoff) (fig. 36): Five teeth line the margin of the declivity on each elytra. The center tooth is most prominent. The apical margin is strongly elevated. Length is 3.0-3.8 mm.
I. calligraphus (Germar) (fig. 37): There are six teeth on the margin of the declivity. The third tooth is stout and curved downward at the tip. The apical margin is acutely elevated. Length is 4.0-6.0 mm.

Pityophthorus Eichhoff (fig. 38): The female of this small (1.6 mm) scolytid has long golden hairs on the front of the head; male hairs are shorter and less numerous. The head is covered by the pronotum. There are numerous elevations (asperities) on the pronotum. Antennae are clubbed. Crypturgus aleutaceus Schwarz (fig. 39): This is the smallest (0.9 mm) insect associate of the SPB. Head is visible from above, and the antennae have three segments, the third much larger than the others. Gnathotrichus materiarius (Fitch) (fig. 40): The prothorax summits well before the middle of this small scolytid (3.0 mm). It is dark brown and has slightly pale elytra. The head is not visible from above. Antennae are clubbed.	Figure 38
	Figure 39
	Figure 40

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