Right: Rhodobaenus quinquepunctatus, Cocklebur Weevil. Length 5-8 mm.
The two beetles shown here are very closely related, and even share some of the same food plants. Among the traits that help identify Rhodobaenus quinquepunctatus (above) are a black area at the rear of the elytra too large to really call a spot, and the large elongated spot at the center of the pronotum. This beetle, at 5-8 mm, is smaller than its congener shown below.
Left: the Ironweed Curculio, Rhodobaenus tredecimpunctatus. Length 7-10 mm.
As one might expect given the name Ironweed Curculio, this species feeds on Ironweed, but it also feeds on other members of the Aster family including Cocklebur, the plant for which the other Rhodobaenus weevil on this page is named. In fact, some older books call this species "Cocklebur Billbug," demonstrating once again why scientific names are preferable to common names.
Rhodobaenus tredecimpunctatus lacks the large black area at the rear of the elytra, and its center spot of the pronotum is smaller and not so elongated. This species is somewhat larger than R. quinquepunctatus.
Insects of West Virginia