round-necked longhorn beetle

not listed

NNR - Unranked

not listed

Round-necked longhorn beetle is a common, medium-sized, wood boring beetle. It occurs in the United States from Maine to northern South Carolina, west to Minnesota, Illinois, and Georgia. It also occurs in southern Canada from Nova Scotia west to Alberta. Adults are found from May to early August in deciduous forests. They feed on the pollen of many flowers in numerous plant families. The larvae feed on the rotting wood of hardwoods, especially maple.

Adults are ⅜″ to ⅝″ (10 to 15 mm) in length. They are black with bright yellow markings. When in flight they resemble a yellowjacket or paper wasp. This is an example of Batesian mimicry, mimicking the defensive coloration of a defended species. The body is elongated, rather robust, and somewhat cylindrical. It is constricted between the thorax and the abdomen, forming a distinct rounded “neck”.

The head is large and entirely black. The face is slanted forward or nearly vertical. There is no ridge (carina) on the front of the head. The compound eyes are deeply notched. The small antennae-like structures (palps) emerging from the lower jaws (maxillae) are blunt or straight across at the tip, not pointed. The antennae are slender, thread-like, and long, at least half as long as the body. They are mostly reddish-brown but the last 4 to 5 segments are black.

The exoskeletal plate covering the thorax (pronotum) is black, rounded on the sides, widest near the middle when viewed from above, and strongly convex when viewed from the side. It is densely pitted (punctate), but it does not have a transverse ridge. There is a single, narrow, yellow band on the front and lateral margins that extends only slightly onto the rear margin on each side. The small plate between the wing bases (scutellum) is yellow.

The hardened forewings (elytra) are broad at the base, round at the tips, and black with yellow markings. On each elytron there is an oblique, oval spot in the basal third; a U-shaped band extending from the inner margin (suture), back to the middle, then forward and outward to near the leading edge (costal margin); and an oblique bar beyond the middle.

The legs are long and mostly reddish-brown. The third segment (femur) on each leg is narrow and reddish-brown at the base, swollen (clubbed) and black from the middle to the tip. The last part of each leg (tarsus), corresponding to the foot, has five segments. The first segment is very long. The fourth segment is very short and is concealed within the lobes of the heart-shaped third segment, making the tarsus appear to have only four segments.

Total length: ⅜″ to ⅝″ (10 to 15 mm)

woodlands

One generation per year: May to early August

Rotting wood of hardwoods, especially maple

Flower pollen

Sources

7, 24, 27, 29, 30, 82, 83.

Location: Whitewater State Park, along the Trout Run Creek Trail