A new species of Bracon (Hymenoptera: Braconidae) parasitic on alien sweetpotato weevils in the south-west islands of Japan.
A new species of braconid, Bracon yasudai Maeto et Uesato sp. nov., is described here from the south-west islands of Japan. It is a solitary idiobiont ectoparasitoid of the larvae of the West Indian sweetpotato weevil, Euscepes postfasciatus (Curculionidae), and the sweetpotato weevil, Cylas formicarius (Brentidae), both feeding on Ipomoea batatas (L.) (Convolvulaceae). The percentage parasitism of the braconid on E. postfasciatus in the vines of I. batatas was 19.9-40.7% in the field. Bracon cylasovorus (Rohwer) reared from C. formicarius in the Philippines is also described.