Molecular survey of endosymbiotic bacteria in the honeybee ectoparasite Varroa destructor in Türkiye

Abstract

Varroa destructor is recognized as the predominant ectoparasite affecting Western honey bees (Apis mellifera L.) globally, representing a significant threat to the sustainability of bee colonies. The bacterial community of the digestive system and body tissues of Varroa mites has been documented in previous studies, however, the diversity and prevalence of detected endosymbiotic bacteria remain limited. In this study, the existence of four commonly found endosymbiotic bacteria including Wolbachia, Cardinium, Spiroplasma, and Rickettsia was investigated in various Varroa mite populations collected from Turkish apiaries. Almost half of the sampled population was infected with at least one endosymbiotic bacteria. Wolbachia endosymbiont was detected as the most prevalent genus, observed in six populations followed by Cardinium present in three populations. Furthermore, Spiroplasma and Rickettsia endosymbionts were each detected in one sample. To our knowledge, this study provides the first molecular characterization of Cardinium endosymbionts in V. destructor. The identity of 16S rDNA sequences of Cardinium was 98.9% of the sequence of Cardinium reported from another mite species, Brevipalpus papayensis, in the NCBI database. The study contributes new insights into the endosymbiotic bacterial community of Varroa mites. Understanding the diversity and prevalence of endosymbiotic bacteria in Varroa mites could facilitate the development of targeted management strategies to control Varroa infestations and improve honeybee health.