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Honey-bee colony model for risk assessment.

The ApisRAM project will provide a model of a bee colony, following individual bees through their life cycle and recreating their behaviour and decision-making.


Honeybee-colony weakening and losses have been reported in the EU and worldwide. The way that stressors (biological, chemical and environmental) affect bees and contribute to the current observed trends of population declines is not well understood, neither are the underlying mechanisms, which remain complex given the potential number of combinations and interactions among stressors.

When assessing the risk of pesticides to honeybee colonies, a tiered approach is followed going from the most conservative (on individual bees and under laboratory conditions) to the most realistic (on colonies and under (semi)field conditions). Current tests do not reflect well the exposures of real colonies, which vary in time and space within a complex landscape. This is, in particular, because semi-field tests are too short in duration and tests in the field have plot sizes that are too small. The development of a mechanistic model reflecting this complexity can be a useful tool for the risk assessment of honeybee colonies exposed to multiple stressors that vary in time and space, at the landscape level.

The project is part of the EFSA’s MUST-B (MUltiple STressors in Bees) project. MUST-B aims to develop a holistic approach on the risk assessment on multiple stressors in bees to be formalized through an Opinion of the Scientific Committee. The MUST-B project will culminate in an overarching Scientific Opinion that will bring together and synthesize the findings of the various activities including the development and testing of ApisRAM.

SESS is a fully involved in the development of this model, utilizing the ALMaSS landscape simulation and provide the bees with a dynamic and realistic environment, including the multiple stressors (pesticides, diseases, parasites, and weather). The in silico colony will also simulate bee-keeping management and can be used to evaluate the likely effects of changed landscape use, bee keeping or pesticide exposure on honey bees.


1. EFSA: MUST-B project

2. EFSA: Development of a mechanistic model to assess risks to honeybee colonies from exposure to pesticides under different scenarios of combined stressors and factors


Xiaodong Duan

Postdoc Department of Ecoscience - Biodiversity and Conservation

Project duration



European Food and Safety Authority



September 2021, På vej mod udvikling af en ny pesticid risikovurdering for bier, Tidskrift for Biavl