Landscape floral resources provided by rapeseed correlate with next-year reproduction of cavity-nesting pollinators in a national participatory monitoring program

Wild pollinators depend on floral resources available in the landscape, partly provided by mass flowering crops (MFCs), such as rapeseed or sunflower. MFCs are however often grown conventionally, implying insecticide use, with potential negative effects pollinators. To understand whether and to what extent these could contribute maintenance of pollinator populations, we investigated inter-annual correlation between MFC reproduction cavity-nesting (solitary bees wasps) at a national scale. We studied standardized citizen science dataset, which farmers collected data abundance sealed tubes trap nests, 2012 2017, nearly 600 fields distributed across France. modelled relation nesting landscape current previous year, taking local farming practices into account. Pollinator was positively correlated quantity year preceding observations, well area permanent meadows. On contrary, found more variable relations sunflower resources, depending type sealing material, hence likely phenology Our models also confirm that should be accounted for when assessing influence context, although their were difficult interpret. Solitary bee wasp is durably affected cover. Moderate areas may help maintain pollinators, combination semi-natural habitats, provide diverse stable food sites.