A Cultural Threat: <i>Gastrallus pubens</i> Fairmaire (Coleoptera, Ptinidae) and Biodeterioration of Rare Books in Italy

Libraries often face biodeterioration caused by various biological agents, particularly fungi and insects, which harm their collections. The beetle Gastrallus pubens Fairmaire 1875 (Coleoptera: Ptinidae), once infrequently documented within European libraries, is recently emerging as a significant menace to the preservation of rare books. In this study, a G. pubens infestation occurring in an historical library hosting a unique collection of rare books dating between the sixteenth and eighteenth century is described. The observations highlighted a serious attack as many of the books showed damages with deep galleries burrowed by larval activity and holes determined by the emergence of adults. In this work we provide illustrations for the identification of adult G. pubens adults’ and further observations on the morphology of this species. High-resolution photographs in this study complement detailed morphological descriptions, aiding in accurate species identification and can serve as a practical tool for researchers, curators, and conservators. Finally, we discuss the implementation of integrated pest management (IPM) procedures, recommended to the library curator, aimed at controlling biotic infestations to mitigate G. pubens damage.