Up to now, global conservation priorities are far from incorporating megadiverse invertebrate taxa. Thus, an important emerging field in biological conservation is how we might manage landscape to preserve insects. In this study, we analyze the efficacy of Italian reserve network for protecting multiple saproxylic beetles, considering both nationally designated areas and Natura 2000 sites. We selected 150 species inhabiting the Italian territory from the European Red List for saproxylic beetles, on the basis of distribution data availability. For each species, a vulnerability score was assigned according to their Red List status, and the species' distributions data were used to perform an irreplaceability analysis. Our analyses show that conservation targets based on geographic range extent are achieved for only 7% of the considered species. We find that 13 species are not represented in any protected area: among these, two click beetle species (Elateridae) are listed in the International Union for Conservation of Nature threatened categories (i.e. Ampedus quadrisignatus EN and Ampedus brunnicornis VU). Our analyses on protected area effectiveness for the conservation of saproxylic beetles showed that nationally designated protected areas are more irreplaceable than a random selection of cells. Surprisingly, the addition of Natura 2000 sites did not improve the species representation. Moreover, these reserves include sites that are not more irreplaceable than a random selection of cells. We identify some currently unprotected areas that protection could prevent from future extinctions and ensure a favorable conservation status of saproxylic beetles. In particular, we find an important stronghold for beetle conservation, which obtained a high irreplaceability score, in the Adige river basin. We recommend the designation of new reserves in this area to complement the existing network and to help guarantee invertebrate saproxylic fauna protection.

The brown marmorated stink bug Halyomorpha halys is an invasive agricultural pest with a worldwide distribution. Classical biological control has been identified as the most promising method to reduce the populations of H. halys. Adventive populations of two candidates for releases, Trissolcus japonicus and Trissolcus mitsukurii, have recently been detected in Europe. To assess their distribution and abundance, a large-scale survey was performed. From May to September 2019, a wide area covering northern Italy and parts of Switzerland was surveyed, highlighting the expanding distribution of both Tr. japonicus and Tr. mitsukurii. Within four years after their first detection in Europe, both species have rapidly spread into all types of habitats where H. halys is present, showing a wide distribution and continuous expansion. Both exotic Trissolcus showed high levels of parasitism rate towards H. halys, while parasitization of non-target species was a rare event. The generalist Anastatus bifasciatus was the predominant native parasitoid of H. halys, while the emergence of native scelionids from H. halys eggs was rarely observed. The presence of the hyperparasitoid Acroclisoides sinicus was also recorded. This study provided fundamental data that supported the development of the first inoculative release program of Tr. japonicus in Europe.

Halyomorpha halys (Stål) (Hemiptera: Pentatomidae) is an invasive alien species and a key agricultural pest. Its native parasitoids (Trissolcus japonicus Ashmead and Tr. mitsukurii Ashmead) have been registered in several countries where H. halys brought dramatic economic losses and where biological control is considered to be the most effective long-term solution. By searching for stink bug egg masses and exposing sentinel egg masses, we monitored the distribution of native and exotic egg parasitoids in Trentino-Alto Adige (Italy), an area where both the host and parasitoids are in expansion. We recorded ten pentatomids, seven parasitoid species, with the first report of Tr. japonicus in this area and a hyperparasitoid. In the assemblage, Anastatus bifasciatus (Geoffroy) and Tr. mitsukurii were the dominant parasitoids, with a different distribution in terms of context and host plants. Sycamore was the host plant where the highest number of naturally laid parasitized egg masses (26%) were recorded. Trissolcus mitsukurii showed the highest parasitism rate, and was often found in apple orchards. The emergence of exotic parasitoids showed a temporal delay compared to native ones. Sequence analysis of 823 bp of the CO1 mitochondrial gene revealed that the recovered Tr. japonicus and Tr. mitsukurii harbored one single haplotype each. These haplotypes were previously found in 2018 in Northern Italy. While sentinel egg masses proved to be very effective in tracking the arrival of exotic Trissolcus species, the collection of stink bug egg masses provided fundamental data on the plant host species. The results lend strong support to the adaptation of exotic Trissolcus species to the environmental conditions of the range of introduction, providing new information on plant host-associations, fundamental for the development of biological control programs.