Storage-associated insect communities in hazelnuts: species, diversity patterns, and ecological implications†

This study presents the diversity and composition of pests infesting stored hazelnuts in the Eastern Black Sea region of Türkiye, a region that supplies nearly 40% of the world's hazelnuts. A total of 174 samples were collected from industrial facilities, merchants/traders, and producer storage units in the districts of three provinces in this region: Ordu, Giresun, and Trabzon. In total, 21 pest species were identified, of which eleven were confirmed as hazelnut pests, six had no reported association with hazelnuts, and four were fungivorous or detritivorous. The most widespread species included Plodia interpunctella, Cadra cautella (Lepidoptera: Pyralidae), Tribolium confusum (Coleoptera: Tenebrionidae), and Carpophilus dimidiatus (Coleoptera: Nitidulidae), with P. interpunctella detected in all surveyed districts. Natural enemies comprised two parasitoids, Habrobracon hebetor (Hymenoptera: Braconidae) and Venturia canescens (Hymenoptera: Ichneumonidae), and a predatory mite Blattisocius tarsalis (Mesostigmata: Blattisociidae), with H. hebetor the most frequently encountered species. Biodiversity metrics, including Simpson D, Shannon-Wiener H', and Whittaker β revealed significant spatial and storage-related variation in community structure. Industrial facilities supported the highest species richness, while storage in bigbags and jute sacks yielded greater diversity than bulk storage, highlighting the influence of storage conditions on insect assemblages. These results demonstrate how storage practices shape insect biodiversity, community composition, and pest-enemy interactions in stored hazelnut. Beyond their applied relevance for integrated pest management, these findings provide a framework for understanding ecological drivers of insect diversity in storage environments.