Halyomorpha halys and its egg parasitoids Trissolcus japonicus and T. mitsukurii: the geographic dimension of the interaction

Halyomorpha halys (Stål) (Hemiptera, Pentatomidae) was accidentally introduced to North America and Europe, becoming a key pest of many important crops. In its native range, it is attacked by egg parasitoids, including Trissolcus japonicus (Ashmead), considered to be the main species, and T. mitsukurii (Ashmead) (Hymenoptera, Scelionidae). Trissolcus japonicus was detected in North America in 2014 and Europe in 2017, while T. mitsukurii was detected in Australia in the early 20th century and in Europe in 2016. Both species now appear established in the new areas. The present study used the MaxEnt algorithm to clarify the geographic dimension of the potential interaction between H. halys and these two parasitoid species, and to indicate where the release of one or the other parasitoid species is more likely to be effective. We found that the suitability for the two parasitoids overlaps the H. halys native range completely. In invaded areas, T. japonicus showed higher potential habitat suitability at the global scale, compared to T. mitsukurii, and also higher potential suitability at lower latitudes at continental and national scales. These results can substantially improve the effectiveness of biological control against H. halys, by targeting the releases of parasitoids to the areas where each species is most likely to succeed.