A taxonomic issue of two species of Trissolcus (Hymenoptera: Platygastridae) parasitic on eggs of the brown-winged green bug, Plautia stali (Hemiptera: Pentatomidae): Resurrection of T. plautiae, a cryptic species of T. japonicus revealed by morphology, reproductive isolation and molecular evidence

Trissolcus plautiae (Watanabe) is known as a major egg parasitoid of the brown-winged green bug Plautia stali Scott, which is a serious pest of various fruit trees in Japan. Although T. plautiae was synonymized with T. japonicus (Ashmead) in 1981, both scientific names have been used for the same egg parasitoid of P. stali for about the past 30 years because of their taxonomic confusion. To promote an effective IPM program for P. stali using its egg parasitoids, we attempted to resolve the confusion by the use of a variety of methods. On detailed observation of adult morphology, we found that sublateral setae on the T1 are present in T. plautiae and absent in T. japonicus, and that this morphological difference is corroborated by more subtle differences between the two species. This finding supports the view that they are different species. The view was also supported by the results of mating experiments to determine the reproductive isolation of T. plautiae from T. japonicus and DNA analysis of these two species. We conclude that T. plautiae is a cryptic species of T. japonicus and resurrect T. plautiae from T. japonicus stat. rev.