Coleoptera (Insecta, Coleoptera) in the entomocomplex of the xylotrophic agaricomycete Cerrena unicolor (Bull.) Murrill (1903) in the Chelyabinsk Oblast (South Urals)

The purpose of this study is to examine the species composition, dynamics, and ecological-trophic structure of the Coleoptera complex associated with the xylotrophic agaricomycete Cerrena unicolor in Chelyabinsk Oblast (South Urals) (See Fig. 1). The material for this research consisted of beetles collected along routes and at test sites, both from the surface and within the fruit bodies (basidiomes) of Cerrena and its mycelial layer (under the bark and within the wood). Routes covered 26 municipal districts and were established across 52 key sections (See Fig. 2). A total of 210 fungal fruit bodies and 20 samples of birch deadwood colonized by fungi were studied (See Fig. 3). To analyze the trophic relationships of mycetophagous beetles, preference coefficients were used to reflect the proportion of specific fungal species in the overall diet of the insects, indicating their food preferences. Twenty-eight species from 11 families were identified. Of these, 7 species from the families Nitidulidae, Latridiidae, Mycetophagidae, and Tenebrionidae were found exclusively at the imago stage. Larvae of 7 species from the families Cerylonidae, Monotomidae, Colydiidae, and Melandryidae were found in white rot of birch caused not only by C. unicolor, but also by other xylotrophic fungi; their adults were found on fruit bodies. The remaining 14 species from the families Staphylinidae, Trogossitidae, Ciidae, and Melandryidae live and develop within basidiomes (See Table 1). A particularly diverse beetle complex (12 species from 7 families) forms during fungal sporulation. At this time, fruit bodies may have high abundance of Scaphisoma agaricinum and Lordithon lunulatus (Staphylinidae), as well as imago Cerylon deplanatum, C. ferrugineum, C. histeroides (Cerylonidae), Epuraea limbata, E. variegata (Nitidulidae), Rhizophagus dispar and Rh. parvulus (Monotomidae), Latridius consimilis (Latridiidae), Bitoma crenata (Colydiidae) and Melandrya dubia (Melandryidae). Dead basidiomes are colonized by Ciidae (Cis comptus, C. micans, Octothemnus glabriculus, Sulcacis nitidus dominate), Orchesia fusiformis (Melandryidae) and Thymalus oblongus (Trogossitidae). The imago stage of Mycetophagus multipunctatus undergoes additional feeding on dying fungi. Moldy, rotting fruit bodies attract Dinaraea aequata (Staphylinidae), imagines of Cerylon ferrugineum, Epuraea rufomarginata, occasionally E. variegata (Nitidulidae), L. consimilis, Stephostethus pandellei (Latridiidae) and Scaphidema metallicum (Tenebrionidae). The ecological and trophic structure of the community of inhabitants of C. unicolor inhabitant community can be summarized as follows (See Fig. 5). Specialized mycetobionts (carpophorophages, sporophages) are 12 species of beetles from 4 families. An open-living lifestyle is characteristic only of S. agaricinum. By food specialization, it is a typical mycetophagus, consuming exclusively living fungal tissue (basidia and spores). Regarding trophic breadth, it is a polyphagous species that colonizes fungi from various orders. The remaining 11 species are secretive, developing in the thickness of fruit bodies. Among these, Mycetophagus multipunctatus (Mycetophagidae), found in Cerrena basidiomes at the imago stage, also develops in other fungi of various states (living, dying, and dead), making it a complete mycetophage. Regarding the breadth of trophic connections, it is polyphagous. All Ciidae and O. fusiformis are mycetosaprophages that inhabit dead fruiting bodies. Polyphagous species include C. comptus, C. fissicornis, O. glabriculus, Rhopalodontus strandi, Sulcacis fronticornis, S. nitidus and O. fusiformis (populate fungi of the orders Hymenochaetales, Polyporales, Russulales), oligophages - Cis boleti, C. micans, C. setiger - develop in mushrooms of the order Polyporales. Eurybionts, which inhabit various substrates such as soil, litter, animal corpses, accumulations of decaying plant debris, dead wood, and occasionally mushrooms (more often found on them during the imaginal stage), are represented by 16 species from 9 families. Obligate myceto-phages, numbering 10 species from 6 families, feed exclusively on fungi regardless of their environment, with some specialized for specific fungi D. aequata and Lordithon lunulatus found under the bark of dead trees, in decaying plant debris, in the litter, where they feed on fungal mycelium, and fruiting bodies of many soil and tree fungi of various states. Beetles of the genera Cerylon, E. limbata, E. variegata, Rh. Parvulus, L. consimilis and S. metallicum are xylophilic species, typically developing under the bark of dead trees by exploiting certain fungal groups. Myxophages - species combining different nutritional modes, including mycetophagy - are represented by 6 species from 5 families. The species S. pandellei inhabits diverse decaying organic matter, while the xylophilic species include Th. oblongus (which can complete its life cycle in some tree fungi), E. rufomarginata, Rh. dispar, B. crenata, and M. dubia. Overall, the entomocomplex of C. unicolor includes coleopterans characteristic of many fungi in the order Polyporales, which produce annual or annual-wintering fruiting bodies of leathery-cork or cork consistency (Bjerkandera adusta, Coriolopsis trogii, Daedaleopsis confragosa, D. tricolor, Lenzites betulinus, Trametes gibbosa, T. hirsuta, T. ochracea, T. pubescens, T. suaveolens, T. versicolor) across Europe, European Russia and Western Siberia. The article contains 5 Figures, 1 Table, 29 References. I express my sincere gratitude to D.V. Akhremov, A.N. Burov, S.V. Gagare, A.I. Gladkov, V.P. Zaritsky, A.V. Zaikin, N.I. Koltakov, A.N. Lavrov, A.N. Luginin, O.P. Malykh, N.N. Pavlov, O.N. Perepelkin, V.D. Prosvetov, S.V. Samarin, B.Yu. Sarattsev, I.P. Khudyakov, A.S. Chaikin, D.A. Yasko for assistance in organizing expeditionary research. The Author declares no conflict of interest

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