Genotype environment interaction theorem

In this deliverable, we investigated the impact of mobility in the beekeeping sector by challenging the genotype-environment interaction (GEI) hypothesis. We analysed both conventionally managed Varroatreated colonies and Darwinian honey bee populations that have survived several years without treatment.
This reciprocal translocation experiment across different geographical transects aims to improve our understanding of the colony performance in relation to local adaptation to climatic conditions and Varroa populations. It also evaluates current best practices that promote locally adapted honey bees and assesses whether such colonies have the capacity to adapt rapidly to new environments.
To address these objectives, we i) designed the protocol for a translocation study, ii) followed the rules and regulations imposed by the EU, iii) installed hive monitoring systems for automated data collection, iv) investigated the apiary vegetation cover and v) compared survival rates, evaluating the performance of translocated colonies between 8 partners. Five partners exchanged conventionally managed Varroa-treated colonies, while 3 exchanged established Darwinian colonies that have survived without Varroa treatment for more than 5 years, alongside conventional control colonies.
These were our key findings: i) we developed and successfully applied a protocol for translocation experiments using package hives to overcome potential problems with different hive types; ii) we complied with all applicable regulations; however, because of some inconclusive results of the sanitary control, a ban was imposed on the import of colonies into Norway and the translocation plan had to be redrawn; iii) hive monitoring systems were installed, but due to technical issues the recorded data sets of several apiaries were incomplete, limiting the comparison of the mass gain over time. However, in apiaries where the data set was of satisfactory quality, no differences in foraging patterns could be found between translocated and local control colonies. iv) The preliminary analysis of Land Class using CORINE for each apiary showed significant differences in land class for each participating partner, and v) we found no negative effect of colony translocation on winter survival, irrespective of the colony type (conventional versus Darwinian). Further, we found substantial variability in spring survival among partners. From a biological perspective, these results imply that, among colonies that have already passed the winter period, survival during spring is not strongly structured by origin. Instead, it is likely influenced by a combination of local environmental conditions,
management practices, and the intrinsic condition of colonies emerging from winter. In short, based on colony development and survival rates, we demonstrated the extent of adaptive plasticity of honey bee colonies in response to climatic conditions and different environments.