Review of Bee Health

How can scientists assess the health of a honeybee colony?  A piece of work we have just completed at EFSA helps to answer that question. The outcome of the HEALTHY-B project is a toolbox that can be used by anyone seeking to assess bee health “holistically” i.e. taking into account chemical, biological and physical stressors. The toolbox has already been used in EFSA’s MUST-B project to generate a conceptual model for assessing the risk to honeybee colonies from exposure to pesticides under different scenarios of combined stressors and factors.

The toolbox will also be used to design the collection of data required to feed this model and it has the potential to be used beyond EFSA’s activities. For instance, it could be used to develop a “health status index” to monitor and compare honeybee health over time across geographical space, to identify key predictors of change in honeybee health and to assess the effect of pesticides on bee health within a geographical location.

So how did we build the toolbox? Firstly, the characteristics of a healthy managed honeybee colony were agreed among bee scientists and stakeholders such as representatives of beekeepers, non-governmental organisations and industry representatives.

In essence, a honeybee colony is considered healthy when its demographic structure, behaviour and production of bee products is adequate in relation to the annual life cycle and geographic location and there is provision of pollination services. This is an important achievement since consensus has been obtained that the presence of low levels of one stressor (e.g. a virus) in a colony might not be sufficient to classify that colony as “not healthy”.

The identified characteristics of a healthy colony were then used as the basis for a hierarchical approach to identify which “indicators” (biotic components) and “factors” (abiotic components) could be measured to assess the health status of a colony.

A workshop with around 55 experts (scientists, risk assessors, risk managers and stakeholder representatives) was held in April 2016 to identify relevant scientific evidence that had not yet been considered by the working group and to discuss harmonisation of measurements and reporting. The methods most suitable for implementation in field surveys across the EU were identified. However, it is clear that efforts are required to further harmonise and validate these before they can be widely applied and results compared between regions.

Finally, the HEALTHY-B working group described the key considerations to take into account when designing a survey on bee health and provided options for data analysis.

Overall, this scientific opinion represents another step forward towards improved data collection, reporting and analysis across the EU that will facilitate risk assessments on bee health by national and European risk assessment bodies. Further engagement and collaboration amongst institutions and stakeholders will be essential for us to continue the journey towards measuring and managing the health status of bees.

Frank Verdonck is a scientific officer at EFSA.