Territorial biodiversity in cropping system and consequences on physico-chemical characteristics of collected pollen

Pollen resources can become a constraint for honeybee in a cereal farming agrosystem and can impact the health of the bee colony. Pollen is an expensive product for beekeepers and there is no artificial food available today able to lead to a full development and protection of the insects. It appears useful to bring knowledge in bee ecology about cropping system capacity to provide food in quantity and quality throughout the year. This survey was devoted to deliver information on (i) the flower range exploited in an agrarian environment in western France, (ii) the physico-chemical composition of the pollen supplied, and (iii) the territorial biodiversity foraged in different periods. The diversity of the collected pollen was studied by palynological analysis, whereas a land use monitoring was recorded. We carried on a complete nutritional component survey of these multifloral samples throughout a year about proteins, lipids, and glucids. A strong decrease in the pollen supply in the food shortage period in late spring, and a large amount of crop pollen in summer is observed. The succeeding contribution of different floral groups such as crop flowers, weeds and woods, clearly shows the influence of agricultural practices as a major food supply factor for pollinators