The outcome of a screening-level honey bee (Apis mellifera) risk assessment using laboratory-based studies of individual larvae may indicate potential risk to honey bee brood that require further refinement involving colony-level studies. At present, different study designs (i.e., OECD Guidance Document 75, acute and chronic Oomen feeding studies, and large colony feeding studies (LCFS)) are available to investigate potential effects on bee brood under more realistic exposure conditions. However, without a decision framework, the choice of the suitbale test design can be challenging. Therefore, a conceptual framework has been developed by the International Commission for Plant-Pollinator Relationships (ICP-PR) Bee Brood Working Group to inform decisions regarding the currently available refinement option(s). The framework consists of a decision tree for determining whether there is exposure of honey bee brood after the use of a plant protection product based on different exposure scenarios. If the outcome indicates that the exposure of the brood cannot be excluded, refinement options are listed. The possible refinement options (i.e., study designs) are tabularised in a table that includes the strengths and limitations of the study.
