Changes in pollinators' flower visits and activities potentially drive a diurnal turnover of plant‐pollinator interactions

Plant‐pollinator interactions are essential to sustaining biodiversity and ecosystem functioning in terrestrial ecosystems and are variable on several spatiotemporal scales. On a fine temporal scale, the responses of pollinators to temperature and floral resource dynamics are likely to be related to the temporal turnover of plant‐pollinator interactions. However, the temporal dynamics of plant‐pollinator interactions on a fine scale are largely unknown. The present study aims to reveal the temporal turnover of plant‐pollinator interactions over a single day and investigates these interactions in semi‐natural grasslands in a Japanese agricultural landscape from the early morning to the evening. The interaction turnover was evaluated as temporal β‐diversity and divided into two components: interaction rewiring and species turnover. Insect species richness and the number of interactions showed hump‐shaped responses to the time of the day, and these responses differed for the different insect groups. Furthermore, the peak time of insect visitation frequency differed among 11 plant species. Interaction turnover (total β‐diversity) in the same day was higher than that in different days. Although interaction rewiring in different days was higher than that in the same day, species turnover had an opposite pattern. Over a single day, the relative importance of interaction rewiring was higher in the morning, while species turnover was higher in the evening. Around noon, interaction rewiring and species turnover were equally important. Therefore, the daily rhythm of pollinator activities and changes in the main floral resources drive the temporal turnover of plant‐pollinator interactions over a single day.