Insect catch at historic libraries in rural and urban settings

The historic libraries of Austria are often elegant classical spaces. The collections are sensitive to damage by insects, such as silverfish (Lepismatidae), biscuit beetles (Stegobium paniceum), spider beetle (Ptinus fur) and the furniture beetle (Anobium punctatum) and a range of other beetles e.g. Dermestidae, which attack carpets and museum objects. Warmer conditions and changes in humidity might encourage new species to appear at these locations. Historic libraries represent a useful group to study, because they have similar collections, with only limited addition of new material and sometimes very few visitors, thus representing a stable indoor ecosystem. The five monastic libraries in the study occupy a range of settings, from rural to urban. Additionally, there were three research libraries in Vienna. Insects were caught over several years (up to 10) from the eastern parts of Austria using sticky blunder and pheromone (webbing clothes moth) traps. Higher annual catch rates were found in more rural monastic settings and revealed a less even spread of species (a high Gini coefficient) than at urban sites. The Shannon diversity was higher in the urban research libraries. Species within the same family can show differences in preference: silverfish Lepisma saccharinum (rural), Ctenolepisma longicaudatum (urban) or C. calvum (urban), carpet beetles Anthrenus museorum (rural) and A. verbasci (urban). The differences may be a function of the land use, climate, air pollution or human activities. The work suggests that managing insects in these libraries need to account for differences between rural and urban locations.