Relation between the reproductive system in drones of Apis mellifera and the level of affection of Varroa destructor

Abstract

Currently, Varroosis is the illness that causes the most damages in the beekeeping activity across the world. It is caused by Varroa destructor, an external parasite, specifically, a mite. It affects both larvae and adult bees. It does not only affect them because of its plunderer action, but also because it favors the appearance of viral and bacterial infections. It is considered an endemic disease in the European Union, thus making it the only apiarian illness that must have, at least, a yearly treatment of the affected hives. Because of how important and impactful Varroosis is in our country, this project is focused on the study of how these parasites affect the reproduction, and, more precisely, how much they influence the reproductive system of the drones, focusing on macroscopy and histological changes between drones from different hives with different Varroosis infestation levels. For this purpose, numerous drones were captured from four different colonies of the Gran Canaria Island (during June of 2023). All the samples were classified by young and adult individuals based on the results of the macroscopic study, specifically on their testes size, and the level of infestation. There were no remarkable results regarding the microscopic study, but the measures taken at the macroscopic study showed a direct correlation between the weight and length of the testicles, and the level of affection of Varroa in the hives. As this is the only study based on the relationship between the reproductive tract of drones and V. destructor in the hives, these results cannot be compared to other articles, therefore, this data should be studied further in the future in order to gain a deeper level of understanding regarding the reproductive system and the effects of parasites on honeybees.