The life and death of barn beetles: faunas from manure and stored hay inside farm buildings in northern Iceland

1. Subfossil beetle remains from archaeological sites have proven invaluable for examining past living conditions, human activities, and their impacts on landscapes and ecosystems. 2. In Iceland, specific economic practices (e.g. land management and natural resource exploitation) and major historical events (i.e. colonisation, economic intensification and commercialisation, and urbanisation) have affected local environments and left recognisable traces in the beetle subfossil record. 3. Understanding the ecology of synanthropic beetles is crucial if they are to be employed in high-resolution reconstructions of past lifeways and their ecological impacts, yet, because buildings' interiors are rarely the object of systematic entomological research, the ecological requirements of many such species are poorly understood. 4. A survey was conducted of live and dead beetle faunas from habitats that have so far been largely neglected by entomological research: stable manure and stored hay inside farm buildings, two key facets of a northern European pastoral economy. 5. The present results clarify the ecological requirements of some under-studied synanthropic beetles and the processes by which their exoskeletons may become incorporated into the archaeological record while also producing new records of exotic species recently introduced to Iceland. 6. This paper provides crucial guidance for the interpretation of archaeological beetle assemblages and highlights the potential of further investigations of indoor insect faunas for clarifying the causes, processes, and ecological impacts of recent bio-invasions.