Prevalence and pathogen detection of Varroa and Tropilaelaps mites in Apis mellifera (Hymenoptera, Apidae) apiaries in South Korea

Abstract

The honey bee is an important pollinator of wild plants and crops and provides various useful products for humans. Infestations by honey bee mites damage the honey bees’ health, decrease their lifespan, and increase their viral susceptibility. In this study, surveys were conducted throughout South Korea in 2019 to investigate the status of honey bee mite infestation. Mite samples were collected for species identification, and estimation of infestation levels from 47 apiaries in 12 regions was conducted. Mite species were identified by morphological characteristics and genetic analysis using cytochrome c oxidase subunit I (COX1). The results showed that 93.6% of the apiaries were infested by honey bee mites, of which 85.1% and 76.6% of the apiaries were infested by Varroa spp. and Tropilaelaps spp., respectively. Furthermore, 68.0% were co-infested by both honey bee mites. Additionally, 82.5% of the apiaries with Varroa spp. showed infestation rate with >3 mites per 100 bees, the infestation level could result in winter losses of honey bee colonies. Species identification revealed that all mites from the apiaries in South Korea were Varroa destructor and Tropilaelaps mercedesae. Importantly, these two mite species were determined to be vectors of one to nine honey bee pathogens in real-time polymerase chain reaction detection. The most prevalent pathogen was the deformed wing virus, followed by the Israeli acute paralysis virus and chronic bee paralysis virus. The results of the surveys are important for estimating the economic losses caused by honey bee mites and establishing a possible strategy for controlling mites and mite-borne transmissible pathogens in South Korea.