Ovipositional Responses of Three Opiine Fruit Fly Parasitoids (Hymenoptera: Braconidae) to Gall-Forming Tephritids (Diptera: Tephritidae)

In the laboratory, we evaluated ovipositional responses of three insectary-reared opiine parasitoidsDiachasmimorpha tryoni(Cameron),Diachasmimorpha longicaudata(Ashmead), andPsyttalia fletcheri(Sivilstri) to galls formed by three nontarget tephritidsEutreta xanthochaetaAldrich,Procecidochares alaniStekyskal, andPhaeogramma lortnocoibonAsquith. Individual gravid females of the three parasitoids were released onto stems of each gall flyʹs host plant containing single galls that contained late instar flies, and the parasitoidsʹ oviposition responses were recorded. Although the galls formed by the three nontarget tephritids had similar color (green), shape (spheroid), and size (7–11 mm), responses of the three opiine parasitoids to the galls varied with parasitoid as well as fly species. Thirty-eight and 26% of gravidD. tryoniandD. longicaudata,respectively, probed inE. xanthochaetagalls, which resulted in 28 and 20% of the resident larvae receiving parasitoid eggs. Few (<3%)P. fletcheriprobedE. xanthochaetagalls, and no resident larvae received parasitoid eggs. All three species of parasitoids lacked ovipositional response toP. alaniandP. lortnocoibongalls; thus, no fly larvae of these two tephritids received any parasitoid eggs. BothD. tryoniandD. longicaudataprobed significantly more frequently and for significantly longer periods in lantana stem galls than in nongalled stems. These results indicate that bothD. tryoniandD. longicaudatahave the ability to recognizeE. xanthochaetagalls as potential host microhabitats and fly larvae as hosts. The relevance of these findings to the potential nontarget impacts of opiine fruit fly parasitoids is discussed.