Tropilaelaps mercedesae: an emerging global threat to apiculture - a comprehensive review

Honey bees (Apis spp.) are key pollinators in agricultural and natural ecosystems; however, their populations are declining due to multiple interacting stressors and their synergistic effects, including parasitic mites. While Varroa destructor is widely recognized as the primary global driver of colony losses, mites of the genus Tropilaelaps, particularly Tropilaelaps mercedesae, are emerging as a serious and still underestimated threat. Native to Asia and naturally associated with wild hosts such as Apis dorsata, T. mercedesae has successfully transitioned to managed Apis mellifera colonies and is now widespread across much of Asia. Recent reports from Central Asia and the Caucasus and western Eurasian regions (including Georgia and Russia) indicate that this species is undergoing an ongoing westward expansion toward Europe. Its biological traits-including an extremely short reproductive cycle, obligate dependence on sealed brood, high dispersal capacity, and the potential to transmit viruses such as deformed wing virus (DWV)-facilitate rapid population growth and severe colony-level damage, particularly in A. mellifera, which lacks effective behavioral defenses against this mite. This review synthesizes current knowledge on the taxonomy, morphology, life cycle, host-parasite interactions, geographic distribution, and spread of Tropilaelaps mites, with emphasis on T. mercedesae. It also evaluates available diagnostic approaches, including brood-based methods, adult bee-based methods, and natural mite-fall techniques. Furthermore, evidence on chemical and biotechnical control strategies is summarized, and their strengths, limitations, and integration within an Integrated Pest Management (IPM) framework are discussed. Overall, current findings highlight the urgent need to strengthen surveillance, standardize diagnostic protocols, and develop sustainable control strategies to prevent the global spread of Tropilaelaps mites.