BEERAD

Human activities linked to nuclear industry generate ionizing radiation (IR). However, their ecotoxicological properties are poorly studied on non-human organisms. In radio-contaminated areas, there is no scientific consensus concerning their effects on structure and functioning of the ecosystems, and the potential underlying mechanisms of their action are poorly known. Therefore, it is important to acquire data on the potential effects of IR on ecosystems both in experimental and realistic conditions. This project will try to estimate the environmental consequences of a major nuclear accident by studying an emblematic of pollinating insect, the honeybee, which presents scientific, economic and societal stakes, through the services provided by this species to the society and ecosystems. This project will also contribute to improve knowledge on effects and mechanisms of action of IR on honeybees, by using a combined approach of laboratory and field experiments and could allow to foresee more global consequences on pollinators responsible for a great part of vegetal biodiversity. The main objectives of the project are: - To define the exposure conditions both in laboratory and field experiments (in order to compare results obtained via these two approaches) and measure in both conditions the real external dose rates experimented by the bees by means of carried micro-dosimeters; these values, in addition to the internal dose rates, will give an accurate estimation of the total dose rates absorbed by bees (WP1), - To measure the physiological and toxico-pathological effects induced by IR at sub-individual levels including molecule, cell and tissue, particularly with response to an infectious agent (WP2), - To measure the effects induced by IR at individual and populational levels through the effects on reproduction/development and cognitive process (WP3), - Compare both types of exposure (laboratory/field), integrate the responses and extrapolate to other living organisms (other bee species, other pollinating insects) through modelling in order to conclude on the level of effects of IR on bees and other pollinating insects (WP4). Expected results cover a large broad of domains: (i) what are the accurate absorbed (external + internal) dose rates and doses experimented by bees, (ii) what are the modes of action by which IR induce adverse effects in bees, (iii) which physiological and toxico-pathological parameters are affected by IR, with a focus on combined effects of IR on sensitivity of bees to pathogens, (iv) which parameters are modified by IR at the colony level, including hive production (in relation with ecosystem services), (v) what is the resilience of hives exposed to IR during an apicultural season, (vi) if bees exposed in the field are more or less sensitive to IR than bees exposed in the laboratory (comparison of responses) and (vii) through modelling approaches, what can be the expected consequences of IR exposure on other pollinating insects. Our results will offer the possibility of a better risk assessment by a better prediction of the biological responses induced by IR on pollinating insects. This project is innovative for several reasons. It proposes (i) to study the effects of IR on honeybees, very poorly known up to now, (ii) to establish a basis of knowledge on mechanisms of action of IR in honeybees and (iii) to relate responses observed at the cellular/organ scale to integrative process at the individual/population scale by studying reproduction and repercussions of effects at the colony level. Moreover, the project will combine experiments in the laboratory and in the field, more representative of the environment. This complementarity will serve to draw useful conclusions for the environmental radioprotection. The benefits of this program can be expected at scientific, agro-environmental and socio-economic levels.