Drawing together the results of INSIGNIA-EU

Twenty three members of the INSIGNIA-EU consortium, representing all of the collaborating organizations, met recently for three days at the Escola Superior Agrária, Instituto Politécnico de Bragança, Portugal to review the vast body of results obtained from the sampling programme carried out by the beekeeper Citizen Scientists in all 27 EU Member States over nine sampling rounds during 2023. Reports were presented by the leaders of each of the eight Work Packages that make up the INSIGNIA-EU project. The reports covered the process of obtaining the samples, any lessons learned from the experience, discussion of the methods used, summaries of the preliminary results, and immediate conclusions to be drawn for each section. This led to long discussions about how the results should be fully analysed and interpreted, and any lessons learned which can be used to further refine the protocols for future use.

It was agreed by all, that overall, the project had been a very great success. The system employed, with National Coordinators in each Member State in regular contact with the consortium itself and with each other through the programme of NatCo cafes, had ensured that the Citizen Scientist beekeepers remained highly motivated throughout the project. The logistics of centrally buying and distributing all of the necessary materials and equipment had worked well, as had the chosen methods for the transport of the samples. Translation of the detailed picture instruction manuals into 23 languages, together with the many training sessions, hotlines, FAQs and regular contact which resulted, had enabled the beekeepers to diligently collect a very high proportion of the expected matrix samples throughout the season, and then send them to the National Coordinators in each country. Samples were then carefully packed and sent to the analytical laboratories in four countries for the various analyses to be carried out. All of the sampling techniques  consistently worked well, with a very high proportion of the samples received being capable of being successfully analysed. The analytical data have all now been received by the Data Curator, enabling statistical analysis and modelling of the results to get underway.

The team from the University of Almeria, Spain, reviewed the analysis of the non-polar pesticides and other compounds found on the plastic ApiStrips which had been inserted between the combs of each sampling colony. A total of 5,838 ApiStrips were received and analysed for a total of 430 compounds, including all of the pesticides licensed in each Member State and other compounds which were thought probable to occur. In all, 202 different compounds were detected, and these included acaricides used to control varroa mites in the bee colonies, together with many agricultural compounds including insecticides and various fungicides. The results showed that 14 compounds were each detected in more than 20 countries, and four compounds were detected in all 27 countries. On average, 48 different compounds were detected in each country, with an average of 684 total detections in each country over the season. There were considerable variations in both the number of compounds detected and the actual compounds identified between apiaries within each country, between countries, and over the sampling season..

The Benaki Institute, Athens, Greece, reported on the analysis of the honey samples for polar (i.e. water soluble) pesticides which would not be found on the ApiStrips. A total of 1,164 honey samples were analysed, and 73 were found to contain at least one compound. Two compounds were found to be predominant, and two others were less commonly detected.

Wageningen University, Netherlands, reported on the results for heavy metals found in the propolis samples which were collected on plastic screens inserted over the combs. Although there was a decline in the amounts of propolis collected in some countries as the season progressed, a large proportion of the expected samples were obtained. Eleven individual metals were tested for, and the results showed that trends seem to be similar between apiaries and between countries, but on average, lower concentrations of metals were detected in the northern countries compared to the southern countries. It is to be expected that factors such as predominant soil type, climate, and the amount of propolis collected may influence the results.

The Benaki Institute reported on the analysis of the silicone wristbands which had been placed on the bee hive frame tops for Volatile Organic Compounds (VOCs) and PolyAromatic Hydrocarbons (PAHs). A total of 1,216 samples were analysed, and the results showed that nine VOCs were commonly found, with two others less common, whilst six PAHs were commonly found, with three less frequently, and one PAH which was tested for was not found at all. There were no clear trends in occurrence, and it will be difficult to attach the results to particular sources.

The University of Almeria reported on the analysis of the sticky ApiTraps inserted between the hive combs for the detection of microplastics. A total of 2,520 samples were received, of which 2,390 were capable of being analysed. The particles extracted were all classified into fibres, fragments or films, and by colour and type of plastic. The results showed that fibres comprised 80% of all identifications, and those made of polyester (PET) were by far the most common. There was variation between countries, and some were some consistently above or below the average of all 27 EU Member States. There was little variation over the season, and on average, 40 fibres and five fragments and film particles were recovered from every ApiTrap. Blue, black and green were the most commonly occurring colours of particle.

The Instituto Politécnico de Bragança reported on the results of the ITS2 metabarcoding of the pollen samples to determine the plants on which the bees had been foraging. A total of 2,835 samples were received, of which 2,513 were successfully analysed. A few samples, particularly in the later sampling rounds were found to be insufficient in quantity for analysis, and a small number were contaminated by mould, to which pollen is very susceptible.  There was considerable variation between countries, with neighbouring countries tending to form regional groups, but Cyprus and Malta had very different pollen profiles from the other countries. Overall, the most commonly occurring families were the Asteraceae, Brassicaceae, Fabaceae, Plantaginaceae, and Rosaceae, and no single genus was present over all 27 countries. As expected, the pollen sources varied considerably over the season, and in general there was greater diversity in the pollen sources of the southern countries, with the lowest in the northern countries, and there are clear variations between sites of different land use types.

Analysis and modelling of the results is continuing, but raw results, including individual spectrum diagrams showing the botanical origin of the pollens from each hive over the season will shortly be sent to the National Coordinators for distribution to their individual Citizen Scientist beekeepers.

The INSIGNIA-EU consortium would like to thank Alice Pinto and Andreia Quaresma and their colleagues for their hospitality and the excellent organisation of the meeting.