Autumn and night: the neglected side of plant-arthropod interactions

Plant-arthropod interactions are an essential component of ecosystems: arthropods have a key role in plant reproduction and dispersal, both as pollen and seed vectors, and plants can provide trophic resources for arthropods as well as shelters, mating and oviposition sites. However, the knowledge about these interactions is still limited, especially in mountain environments. Moreover, most of the literature focuses on diurnal interactions occurring in flowering, while interactions occurring at other times (e.g., seed dispersal, site of oviposition, foraging or sheltering) have been neglected, especially during night. The aim of this work is to investigate the relationship between autumnal visitors and Androsace brevis, a vulnerable endemic Alpine plant, and to identify arthropod taxa potentially involved in seed dispersal. We used an integrated approach: diurnal and nocturnal video observations, and diurnal manual sampling of plant visitors. The two sampling methods highlighted the presence of a diverse diurnal community (video observation: Hymenoptera, Coleoptera, Collembola, Diptera, Lepidoptera, Araneae, Hemiptera; manual sampling: Acari, Hymenoptera, Araneae, Coleoptera, Diptera). Nocturnal video observations revealed the presence of visitors, too (Opiliones, Collembola, Araneae, Hymenoptera, Chilopoda). Seed dispersers were not detected, but the high level of observed biodiversity indicates that A. brevis might represent an important resource for arthropods, in particular for trophic activity and sheltering.