Genetic diversity among Neoleucopis (Diptera: Chamaemyiidae) associated with Marchalina hellenica (Hemiptera: Marchalinidae) in Greece and Italy (Ischia)

<h4><b>Abstract</b></h4><h4>1. Marchalina hellenica (Gennadius) (Hemiptera: Marchalinidae), endemic to Greece and Türkiye, infests various pine species in both countries. Apart from its native range, this species has been recorded infesting pine trees in Italy [Campania (island of Ischia) and Marche regions], Croatia, and recently in Australia. While not a severe pest in its native habitat, M. hellenica has been found to negatively impact pines in the invaded regions.</h4><h4>2. Neoleucopis kartliana (Tanasijtshuk) (Diptera: Chamaemyiidae), a key natural enemy of M. hellenica in its native range, was introduced from Greece to Ischia as a biological control agent. In the current study, Neoleucopis populations from 22 sites across Greece and six sites from Ischia were examined using DNA barcoding and morphological traits to determine their identities and elucidate their distributions in Greece.</h4><h4>3. This integrated approach allowed the separation of three genetically diverged mitochondrial DNA (mtDNA) lineages within Neoleucopis, leading to the conclusion via morphology that there were possibly two additional species besides N. kartliana. The three Neoleucopis mtDNA lineages were unevenly distributed in Greece, and all individuals screened from Ischia were identified as N. kartliana.</h4><h4>4. These findings highlight the need for further taxonomic work and provide a deeper insight into the diversity and distribution of Neoleucopis species in their natural range and Ischia, which are essential for optimizing biological control strategies against M. hellenica in other regions.</h4><h4><br><br><b>Data Overview</b></h4><h4>This dataset contains the data required to replicate analyses in Eleftheriadou et al. [Journal: Agricultural and Forest Entomology, Manuscript: AFE(2025)5149], aiming to 1) utilize molecular methods to differentiate the Neoleucopis attacking M. hellenica in Greece, 2) provide information about the geographic distribution of the Neoleucopis attacking M. hellenica in Greece, and 3) verify which Neoleucopis species was introduced as a classical biological control agent on the island of Ischia. Data cover 22 sites across Greece (Ioannina, Filiates, Igoumenitsa, Parga, Amphilochia, Paravola, Patra, Metohi, Kaiafas, Megalopoli, Korinthos, Attica (Paleo Faliro and Kesariani), Xirovrisi, Volos, Drama, Amphipoli, Sani, Stagira-Stratoni, Makriyalos, Larissa, and Thessaloniki, and Lefkada island) that were sampled over 24 days from late May to mid-June 2022 to determine the identity and distribution of Neoleucopis attacking M. hellenica within the country, and six sites in Italy (Ischia) (Pineta Degli Atleti, Giardino Pubblico Porto, Porto d’Ischia Parking, Lacco Ameno, Forio, Serrara Fontana) to identify the Neoleucopis species present on the island (2023-2024). </h4><h4>Data were analyzed targeting the standard DNA barcoding fragment within the 5′ region of the mitochondrial cytochrome c oxidase subunit I (mtCOI) mitochondrial gene (658 bp). The resulting haplotypes have been uploaded to the NCBI database (Accession Numbers available).<br></h4><p></p>