Rhyssa crevieri (Provancher), a primary parasitoid of Siricidae wasps, and the Holarctic poemeniine ichneumonid, Pseudorhyssa nigricornis (Ratzeburg), a cleptoparasitoid of Siricidae via its parasitoids (Ichneumonidae: Rhyssinae), were reared from two stands of Scots pine (Pinus sylvestris L.) and red pine (P. resinosa Ait.) infested with the exotic siricid Sirex noctilio F. near Tully (Onondaga Co.), New York, in 2010. Previously, P. nigricornis has been recorded from the primary siricid parasitoids Rhyssa persuasoria (in Europe and North America) and R. howdenorum Townes and Townes and R. lineolata (Kirby) (in North America). Peak emergence of P. nigricornis occurred in early May concurrently with R. persuasoria and R. crevieri. A second peak occurred in late May, which overlapped peak emergence of R. lineolata and Megarhyssa nortoni (Cresson). Although 14 individuals of two native siricids, Sirex nigricornis F. and S. edwardsii Brullé, emerged from sampled trees, the number of S. noctilio recovered was far higher (372), suggesting cleptoparasitism of the exotic woodwasp rather than native siricids. Approximately 26% of rhyssine parasitoids in pine stands were cleptoparasitized by P. nigricornis. This study marks the first association of R. crevieri and P. nigricornis with S. noctilio in North America. A diagnosis, color images of characters, and a key are provided to aid in the identification of all parasitoids in this study.
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1 April 2012
Detection and Identification of Two New Native Hymenopteran Parasitoids Associated with the Exotic Sirex noctilio in North America
Christopher R. Standley,
E. Richard Hoebeke,
Douglas C. Allen,
Melissa K. Fierke