Simulation of Varroa mite control in honey bee colonies without synthetic acaricides: Demonstration of Good Beekeeping Practice for Germany in the BEEHAVE model

Isabel Schödl; Richard Odemer; Matthias A Becher; Stefan Berg; Christoph Otten; Volker Grimm; Jürgen Groeneveld

doi:10.1002/ece3.9456

Simulation of Varroa mite control in honey bee colonies without synthetic acaricides: Demonstration of Good Beekeeping Practice for Germany in the BEEHAVE model

Ecol Evol. 2022 Nov 8;12(11):e9456. doi: 10.1002/ece3.9456. eCollection 2022 Nov.

Authors

Isabel Schödl¹, Richard Odemer², Matthias A Becher³, Stefan Berg⁴, Christoph Otten⁵, Volker Grimm^{1

6}, Jürgen Groeneveld¹

Affiliations

¹ Department of Ecological Modelling Helmholtz Centre for Environmental Research - UFZ Leipzig Germany.
² Julius Kühn-Institute (JKI), Federal Research Centre for Cultivated Plants Institute for Bee Protection Braunschweig Germany.
³ Artificial Life Laboratory, Institute of Biology, Karl-Franzens University Graz Graz Austria.
⁴ Bavarian State Institute for Viticulture and Horticulture, Institute for Bee Research and Beekeeping Veitshöchheim Germany.
⁵ Service Centre for Rural Areas (DLR), Expert Centre for Bees and Beekeeping Mayen Germany.
⁶ Plant Ecology and Nature Conservation University of Potsdam Potsdam Germany.

Abstract

The BEEHAVE model simulates the population dynamics and foraging activity of a single honey bee colony (Apis mellifera) in great detail. Although it still makes numerous simplifying assumptions, it appears to capture a wide range of empirical observations. It could, therefore, in principle, also be used as a tool in beekeeper education, as it allows the implementation and comparison of different management options. Here, we focus on treatments aimed at controlling the mite Varroa destructor. However, since BEEHAVE was developed in the UK, mite treatment includes the use of a synthetic acaricide, which is not part of Good Beekeeping Practice in Germany. A practice that consists of drone brood removal from April to June, treatment with formic acid in August/September, and treatment with oxalic acid in November/December. We implemented these measures, focusing on the timing, frequency, and spacing between drone brood removals. The effect of drone brood removal and acid treatment, individually or in combination, on a mite-infested colony was examined. We quantify the efficacy of Varroa mite control as the reduction of mites in treated bee colonies compared to untreated bee colonies. We found that drone brood removal was very effective, reducing mites by 90% at the end of the first simulation year after the introduction of mites. This value was significantly higher than the 50-67% reduction expected by bee experts and confirmed by empirical studies. However, literature reports varying percent reductions in mite numbers from 10 to 85% after drone brood removal. The discrepancy between model results, empirical data, and expert estimates indicate that these three sources should be reviewed and refined, as all are based on simplifying assumptions. These results and the adaptation of BEEHAVE to the Good Beekeeping Practice are a decisive step forward for the future use of BEEHAVE in beekeeper education in Germany and anywhere where organic acids and drone brood removal are utilized.

Keywords: BEEHAVE; Honey bees; acaricides; beekeeping; drones; education; modelling; pest control; varroa mite.