Halyomorphahalys(Stål) is a severe agricultural pest that is spreading worldwide from its original distribution in Asia. Egg parasitoids from Asia, which play a key role in the population dynamics ofH.halys, are following its host along global pathways. We present the first records ofTrissolcusmitsukuriiin Europe, and ofTrissolcusjaponicusin Italy. Both discoveries were made in northern Italy, whereH.halysis widely present and has reached extremely high population densities in some areas. Given the availability of their host, the distributions and populations of these exotic egg parasitoids are expected to expand, even in the absence of human intervention.
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 is an invasive, widespread stink bug for which only short-term solutions are currently available for pest control worldwide. The need for long-term management solutions for H. halys has driven studies on augmentative and classical biological control of this species, especially by its egg parasitoids. Numerous investigations in Asia, USA, and Europe on native and exotic egg parasitoids of H. halys, and the effects on non-target pentatomids, have improved the global knowledge of parasitoid-host relationships, uncovered new associations, and led to the discovery of new species. This trend continues with Acroclisoides sinicus, a pteromalid that was described in the 1980's from Asia. In this work we report recent findings of this species in North America and Europe. Moreover, we propose that Acroclisoides solus syn. nov., a species described originally from the USA, is conspecific with A. sinicus based on morphological and molecular analysis.
The implementation of conservation actions\ud
requires a reliable assessment of presence and/or abundance\ud
of targeted species. This is particularly difficult\ud
for rare and elusive species. In this study the use of bottle\ud
traps and the effects of two potential baits in relation to\ud
height in the trees were tested to detect presence and assess\ud
abundance of stag beetles (Lucanidae) and flower chafers\ud
(Scarabaeidae, Cetoniinae), an important component of forest\ud
biodiversity. The study was carried out in a flood-plain\ud
forest of northern Italy. Forty-eight handcrafted traps were\ud
assigned to two height categories (1.5–2 m and 10–20 m)\ud
and three kinds of bait: (i) red wine, white wine and sugar,\ud
(ii) red wine, beer and mashed banana, (iii) no bait, as control.\ud
Fieldwork lasted 8 weeks, with 32 surveys, from May to July. Overall, we recorded 399 captures of the following\ud
species: Dorcus parallelipipedus, Lucanus cervus, Cetonia\ud
aurata, Protaetia speciosissima, P.affinis, P. morio and P.\ud
cuprea. Traps baited with red wine, white wine and sugar\ud
showed the highest detection probabilities for all the species.\ud
A clear preference for the canopy layer (traps between\ud
10 and 20 m high) was shown by all species except for D.\ud
parallelipipedus which was mostly captured between 1.5\ud
and 2 m of height. The study period was long enough to\ud
improve ecological knowledge on species phenology, but\ud
not enough to include the whole phenology for all of them.\ud
The method allowed the assessment of population size only\ud
for flower chafer
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