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Drosophila suzukii (Matsumura) (Diptera: Drosophilidae) is an insect pest originating in South-East Asia that has invaded Europe (EU) and the Americas. This insect has caused extensive economic damage to the soft fruit industry in all countries to which it has spread. Drosophila suzukii population management relies primarily on chemical pesticides, an approach with serious drawbacks including the risk of residues on fruit and development of insecticide resistance. Drosophila suzukii dispersal from surrounding vegetation is believed to significantly increase the risk of crop damage. Despite increasing evidence that environmental configuration and composition strongly affect D. suzukii population levels and activity, the effects of landscape and abiotic factors including temperature and humidity on its movement is still poorly understood. For this reason, during the summer of 2017, we employed a mark-capture strategy using protein markers during middle July and early August. Within the experimental setup, flies were captured in food-baited traps, and later analyzed for the presence of the marker through an ELISA procedure. Our data suggest that more suitable temperature, humidity, and a diverse suite of alternative hosts found in the surrounding forest vegetation likely drove the recorded dispersion. Most of the captured D. suzukii marked within the crop were collected in surrounding forest vegetation within 24 hours of the marking event during each of the periods of collection. Results strongly indicated how humidity, temperature and alternative hosts are key drivers of D. suzukii populations in different habitats. [ABSTRACT FROM AUTHOR]

Simple Summary: The invasive spotted wing drosophila, Drosophila suzukii, is a polyphagous species that has become a serious fruit pest worldwide. Biological control plays a key role in the integrated management of invasive insect pests. With the aim to verify whether some parasitoid wasps, being considered as major mortality factors for D. suzukii, followed its host along global pathways, a field survey was conducted by sampling fruits and installing fruit-baited traps near isolated cherry trees within a wide agricultural area. Morphological and molecular analysis revealed three specimens of Leptopilinajaponica in the parasitoid complex collected during the 2019 field survey; this is considered the first record of this larval parasitoid in Europe. A wider survey carried out during 2020 confirmed the presence of an adventive population of the parasitoid. In terms of reproductive biology, L. japonica shows similarity with Ganaspisbrasiliensis, the best candidate for a future program of classical biological control. Interplay among indigenous parasitoids and the newly arrived Asian parasitoid, as well as the interactions of these species with G. brasiliensis, offer a unique ecological context to acquire new insights into the relationship between D. suzukii and its natural enemies and into their role in providing effective control of the pest. Drosophila suzukii (Matsumura; Diptera: Drosophilidae) is a key pest of sweet cherry and small fruits worldwide. Biological control remains unutilized in the framework of D. suzukii management. Nonetheless, natural enemies may play an important role in regulating this pest. We report for the first time the presence of Leptopilina japonica Novković and Kimura (Hymenoptera: Figitidae) in Europe. Two specimens emerged from ripened fruits and one was collected after direct observation on a cherry tree in June 2019. They showed the distinctive morphological traits already described and shared more than 99% sequence similarity with specimens of L. japonica collected in Asia. This first finding was confirmed by a wider survey carried out in 2020; L. japonica emerged from cherry fruit samples collected in five other sites across the Trentino region, suggesting that L. japonica has already colonized a wide area. Detection of this Asian species is relevant to the future direction in managing D. suzukii, both in Europe and North America. In fact, L. japonica showed similarity with Ganaspis brasiliensis (Ihering) (Hymenoptera: Figitidae), the most promising candidate for the classical biological control, in terms of developmental time, egg maturation, host age preference and lifetime fecundity. [ABSTRACT FROM AUTHOR]

Drosophila suzukii (Matsumura, 1931), the spotted-wing drosophila, is a highly invasive fruit fly that spread from Southern Asia across most regions of Asia and, in the last 15 years, has invaded Europe and the Americas. It is an economically important pest of small fruits such as berries and stone fruits. Drosophila suzukii speciated by adapting to cooler, mountainous, and forest environments. In temperate regions, it evolved seasonal polyphenism traits which enhanced its survival during stressful winter population bottlenecks. Consequently, in these temperate regions, the populations undergo seasonal reproductive dynamics. Despite its economic importance, no data are available on the behavioural reproductive strategies of this fly. The presence of polyandry, for example, has not been determined despite the important role it might play in the reproductive dynamics of populations. We explored the presence of polyandry in an established population in Trentino, a region in northern Italy. In this area, D. suzukii overcomes the winter bottleneck and undergoes a seasonal reproductive fluctuation. We observed a high remating frequency in females during the late spring demographic explosion that led to the abundant summer population. The presence of a high degree of polyandry and shared paternity associated with the post-winter population increase raises the question of the possible evolutionary adaptive role of this reproductive behaviour in D. suzukii., (© 2023 The Authors. Molecular Ecology published by John Wiley & Sons Ltd.)