Bees in intensive cereal farming systems: landscape composition influences colony dynamics

International audience

anglais. A five-year long study was recently initiated in western France to determine (i) how the composition of an intensive cereal openfield landscape influences honeybee colony development and performance and (ii) whether honeybees may be used as a model species to assess the management efficiency of natural habitat remnants. Fieldwork was undertaken in a 45000-ha long-term biological research facility where land use,farming practices and natural habitats are spatially referenced and documented in details over the past decade. Flower resources in this openfield landscape are mostly restricted to cultivated rapeseed and sunflower,available over short periods of time (in Mars-April and June-July, respectively). Therefore, we expect that the seasonal food shortage spanning from early May to late June would exert strong constraints on colony dynamics and beekeeping activity, but that the presence of (semi-)natural habitat remnants in the proximity of apiaries may buffer those constraints by providing bees with alternative, steady-state, flower resources. Up to date, one hundred hives where assigned into 20 apiaries, randomly distributed over the study area, and monitored biweekly using common population indicators: number of workers, brood area, hive weight and pollen quantity and species composition. Pollen analyses are carried out on pellets retained by pollen traps at hive entries. After two years of measurements, strong correlations could be established between some indicators of population dynamics on one hand, and some major landscape characteristics on the other hand. The results will be presented and discussed in relation with a contemporary research program on sustainable agricultural systems.