Fungal symbiotic interactions of Ips sexdentatus (Boerner, 1767) in Pinus nigra Arn. in the Western Mediterranean Region of Türkiye

Ips sexdentatus is a destructive bark beetle species distributed widely throughout Türkiye, particularly affecting pine and spruce trees, that has symbiotic relationships with various fungal species, although there is limited information available about these interactions. The aim of this work was to elucidate the fungal interactions associated with I. sexdentatus populations in five distinct Pinus nigra stands in the Western Mediterranean Region of Türkiye. The surface and internal fungal diversity of 250 adult I. sexdentatus collected in the field were determined and a total of 864 pure fungal isolates obtained. The isolates were grouped morphologically and representative isolates from each morphological group were subjected to DNA isolation followed by PCR using fungal ITS (Internal Transcribed Spacer) primers. Fifty-one isolates were identified (1 isolate was identified to class level, 27 to genus and 23 to species), demonstrating the presence of 23 fungal taxa in I. sexdentatus, recorded for the first time globally. In addition, the presence of the entomopathogen Beauveria bassiana, an entomopathogenic species in I. sexdentatus is the first record for Türkiye. The fungal diversity of the sample areas was determined using Shannon–Wiener, Simpson and Bray–Curtis indices. Based on the Shannon–Wiener and Simpson diversity indices, the fungal diversity in the sampled areas was similar. To the best of our knowledge, this is the first report identifying fungal species associated with I. sexdentatus populations in Türkiye.