Review of Sustainable Cryopreservation and Above-Freezing Storage Solutions of European Honey Bee Apis mellifera Drone Semen

The European honey bee Apis mellifera is the main pollinator for most crops used for human consumption. However, a number of diseases, parasites, pesticides and other factors that generally result in the widely described colony collapse disorder weakens honey bee colonies. In order to maintain the existing honey bee germ lines and facilitate the creation of new disease-resistant lines, it is necessary to ensure consistent breeding work, which would also allow the long-term preservation of the unique germplasm lines. One of the most promising solutions for the preservation of honey bee germplasm is the storage of honey bee drone semen. In recent decades, there has been a renewed interest in the preservation of honey bee drone semen using both cryopreservation and above-freezing storage methods. This review summarizes the latest developments in novel sperm storage technologies and their assessment by sperm quality and queen fertility indicators. Additionally, this article analyses the advantages and disadvantages of the reviewed solutions and outlines directions in which additional research would be needed to develop effective, available and affordable drone semen storage solutions. To the best of the authors' knowledge this is the first review of cryopreservation and above-freezing storage solutions of European honey bee Apis mellifera drone semen in the scientific literature.