flatheaded poplar borer

(Dicerca tenebrica)

Conservation Status
IUCN Red List

not listed

NatureServe

NNR - Unranked

Minnesota

not listed

 
flatheaded poplar borer
Photo by Bill Reynolds
 
Description

Flatheaded poplar borer is a medium-sized metallic wood-boring beetle. In North America it occurs in the east from Nova Scotia south to Massachusetts, west to southern Ontario and Minnesota. In the west it occurs from Alaska south to New Mexico, east to Manitoba and Nebraska. It is common, possibly the most frequently encountered Dicerca species in aspen forests. Adults are found from March to November in deciduous and mixed forests. They breed on a variety of trees in the genus Populus. In Minnesota these include bigtooth aspen and quaking aspen. In other areas their hosts include black cottonwood and narrow-leaf cottonwood. Adults feed on these and other Populus species, especially balsam poplar. They are sun loving, and can be seen sitting on logs, trunks, branches, or foliage of their host trees and other trees near their hosts.

Adults are rigid and streamlined. The body is elongated, moderately convex, and broadly flattened. Females are 916 to 1 (14.5 to 26.0 mm) in length and 316 to (4.5 to 9.0 mm) in width. Males are a little smaller, to (15.0 to 21.5 mm) in length and 316 to ¼ (4.8 to 7.2 mm) in width. The color of the upper side is variable, from brass-colored to black, sometimes with a bluish tint, and always with metallic reflections and heavy white or pale speckling. The underside is coppery and iridescent.

The head is flattened. This is the feature that gives the species part of its common name. It is slightly impressed in the middle both on the top (vertex) and in front. The eyes are widely separated. The antennae are moderately slender and relatively short, reaching just to the middle of the plate on the upper side of the first segment of the thorax (pronotum). They have 11 segments. The fifth through eleventh segments are distinctly saw-toothed (serrate). The mouthparts are directed downward.

The pronotum is wider than long. The sides are almost parallel in front, distinctly widened in the middle, and narrowest at the rear. The rear margin has two concave curves meeting in the middle in a convex curve. The surface is coarsely pitted (punctate). There is a distinct, coarsely punctate channel in the middle extending from the rear almost to the front margin, and a smooth raised area on each side of the channel. There is another slightly raised area halfway between the channel and the lateral margins. The plate between the wing bases (scutellum) is small, rounded, and visible.

The wing covers (elytra) are wider at the base than the pronotum. They are almost parallel at the base, widest just beyond the middle, and strongly narrowed to the tip. They are distinctly grooved, especially toward the inner margin (suture). The tips are extended narrowly, stub-like, and are distinctly separated.

The legs are moderately robust. On the male the fourth leg segment (tibia) has a single tooth on the underside. There is no similar tooth on the female. The last part of each leg (tarsus), corresponding to the foot, has 5 segments. There is a pair of claws at the tip of each tarsus.

 

Size

Male total length: to (15.0 to 21.5 mm)

Female total length: 916 to 1 (14.5 to 26.0 mm)

 

Similar Species

 
Habitat

Deciduous and mixed forests.

Biology

Season

March to November

 

Behavior

 

 

Life Cycle

Eggs are laid in wounds, cracks, or crevices in the rough bark of branches and branch stubs that are exposed to sunlight. Larvae bore into the sapwood and heartwood of recently dead wood or in dead parts of living trees. They make large rather openings in the bark when they burrow into it. Development information for North American species is unknown, but this species probably spends three to seven years as larvae.

Adults create large openings in the bark when they first emerge. They hibernate under loose bark in the winter.

 

Larva Food

Sapwood

 

Adult Food

Leaves of trees in the genus Populus, including

Distribution

Distribution Map

 

Sources

24, 29, 30, 82, 83.

7/4/2024    
     

Occurrence

Common

Taxonomy

Order

Coleoptera (beetles)

Suborder

Polyphaga (water, rove, scarab, long-horned, leaf, and snout beetles)

Infraorder

Elateriformia

Superfamily

Buprestoidea (metallic wood boring and false jewel beetles)

Family

Buprestidae (jewel beetles)

Subfamily

Chrysochroinae

Tribe

Dicercini

Subtribe

Dicercina

Genus

Dicerca

   

Subordinate Taxa

 

   

Synonyms

Buprestis tenebrica

Dicerca prolongata

Stenuris tenebrica

   

Common Names

flatheaded poplar borer

poplar dicerca

 

 

 

 

 

 

 

 

Glossary

Elytra

The hardened or leathery forewings of beetles used to protect the fragile hindwings, which are used for flying. Singular: elytron.

 

Pronotum

The exoskeletal plate on the upper side of the first segment of the thorax of an insect.

 

Scutellum

The exoskeletal plate covering the rearward (posterior) part of the middle segment of the thorax in some insects. In Coleoptera, Hemiptera, and Homoptera, the dorsal, often triangular plate behind the pronotum and between the bases of the front wings. In Diptera, the exoskeletal plate between the abdomen and the thorax.

 

Tarsus

On insects, the last two to five subdivisions of the leg, attached to the tibia; the foot. On spiders, the last segment of the leg. Plural: tarsi.

 

Tibia

The fourth segment of an insect leg, after the femur and before the tarsus (foot). The fifth segment of a spider leg or palp.

 

Vertex

The upper surface of an insect’s head.

 

 

 

 

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Charlene

flatheaded poplar borer  

 

sitting on a plastic tarp in the sunshine

 

 

Bill Reynolds

flatheaded poplar borer  

flatheaded poplar borer

Metalic Wood-borer

I don't see this beetle often, just time to time. This one is on an outdoor plastic storage box, thus the strange surface. Taken the image with phone, it just won't sit for a frontal shot.

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Charlene
7/4/2024

Location: Fort Ripley, MN

sitting on a plastic tarp in the sunshine

flatheaded poplar borer

Bill Reynolds
6/8/2023

Location: Pennington Co. MN

I don't see this beetle often, just time to time. This one is on an outdoor plastic storage box, thus the strange surface. Taken the image with phone, it just won't sit for a frontal shot.

flatheaded poplar borer
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Created: 6/11/2023

Last Updated:

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