Trissolcus comperei, a newly-reported egg parasitoid of Halyomorpha halys from China

Native to Asia, the brown marmorated stink bug (BMSB), Halyomorpha halys (Stål) has become a serious invasive pest in North America and Europe. BMSB has an extremely wide host range in both its native and invaded ranges, and can cause severe damage to various tree fruits, vegetables, field crops and ornamentals. Species of Trissolcus are the major egg parasitoids, especially T. japonicus (Ashmead), T. mitsukurii (Ashmead) and Anastatus bifasciatus (Geoffroy) that have recently been studied as biological control agents for this invasive pest. In this study, we report newly a parasitoid parasitizing BMSB eggs collected in Guizhou Province, China, and it was identified as Trissolcus comperei (Crawford) using both morphological and molecular methods. We provide images of T. comperei male, male genitalia and immature stages, and describe some biological characteristics of T. comperei parasitizing BMSB eggs and parasitism capacity. Under 25 ± 1 °C, T. comperei egg hatched within 24 h, larva, prepupa and pupa developed in 1–3, 4–6 and 7–11 d, respectively. The parasitoid could parasitize 0-, 2- and 4-day-old BMSB eggs. Host egg age did not influence emergence rate of adult wasps (90.15–93.33 %). However, both the number of parasitized eggs (0.57–6.07 eggs/ 24 h) and percentage of female progeny (60.00–93.02 %) decreased with increasing host egg age. In addition, we compiled literature to provide a complete list of all 16 known Trissolcus species in China; seven of them have been reported to parasitize BMSB eggs, including T. comperei from this study. This information enriches the knowledge of the egg parasitoids of BMSB. Moreover, the high emergence rate and female-biased offspring of T. comperei could be important attributes as a potential biological control agent for BMSB eggs.