EFSA – PPR panel: Suitability of the BEEHAVE model for its potential use in a regulatory context

The BEEHAVE model was developped in order to simulate the hive population dynamics by considering environmental factors that may influence foraging ability and infectious agents (the Varroa mite and two associated viruses) and other population dynamic parameters that may impact the colony development.

Where relevant the EFSA Panel on Pant Protection Products and their Residues (PPR) evaluated its potential use in a regulatory context. The corresponding statement has just been published (EFSA Journal 2015;13(6):4125).

The overall conclusion is that BEEHAVE performs well in modelling honeybee colony dynamics, and the supporting documentation is generally good but does not fully meet the criteria of  EFSA opinion on the good modelling practice (EFSA PPR Panel, 2014). It is not surprising since the BEEHAVE model was developed before the opinion was published and was not submitted in a regulatory context.

According to the PPR Panel, the model is not yet usable in a regulatory context or to address the risk from multiple stressors at the landscape level. Recommendations for developing the model further are, for example, the development of a pesticide module, adding additional pathogens and interactions between pathogens, parasites and climatic conditions. The supporting data and default parameter values should be further evaluated and justified. The PPR Panel also recommends adopting the model as the basis for modelling the impact on honeybee colonies of pesticides and other stressors but further development should use a standard object-oriented language rather than the current modeling environment (NetLogo).

As regards more specifically to pesticides issues, BEEHAVE is not yet usable in a regulatory context since a pesticide exposure and effect module is missing, Additional outputs would be required in order to interpret the endpoints within the regulatory context (e.g. exposure to pesticides of foragers, in-hive bees and larvae).

BEEHAVE currently uses a very simple representation of a landscape. The current set of default parameter values cannot cover ‘realistic worst case’ scenarios for all regulatory zones. Indeed, there is only one environmental scenario in the present version (European central zone—weather scenarios for Germany and the UK).

When the model is developed further for pesticide authorisation  for the EU (Regulation 1107/2009), at least one representative realistic worst-case scenario for each of the three regulatory zones should be developed, including realistic worst case weather files.

Therefore the model can neither currently be used instead of field studies in higher tiers of the pesticide risk assessment nor to answer questions related to mitigation of the risk from pesticide applications.