For decades, beekeepers have battled the Varroa mite, a tiny parasite that has wreaked havoc on honey bee colonies worldwide. But a new and even deadlier threat is on the march: Tropilaelaps mercedesae, or “tropi.” Experts fear this new mite will cause greater devastation than Varroa, with potentially catastrophic ripple effects for the billions of people who rely on honey bee-pollinated crops.
From Asia to Europe: A Rapidly Spreading Parasite
Tropi’s natural host is the giant honey bee (Apis dorsata) found in South and Southeast Asia. However, the mite has now jumped to the western honey bee (Apis mellifera), the species used by beekeepers globally. This host shift has enabled the parasite to spread westward, with recent detections in Ukraine, Georgia, and southern Russia. Its expected arrival in eastern Europe, followed by a potential spread to North America and Australia, poses a severe risk to global agriculture.
Why Tropi Is a Deadlier Foe
Like Varroa, tropi breeds inside capped brood cells, feeding on bee pupae and transmitting lethal viruses. But its biological traits make it far more dangerous. Tropi spends more time in the protected environment of the capped cells, allowing it to reproduce faster than Varroa. This rapid breeding cycle means a tropi-infested colony can collapse far more quickly. Additionally, while Varroa can survive for long periods on adult bees, tropi cannot. This makes the new mite far less susceptible to the standard chemical treatments used against Varroa, which are designed to be spread throughout the colony on the bodies of adult bees.
A Looming Crisis for Beekeeping and Agriculture
The spread of tropi will not only devastate beekeepers but also the broader agricultural industry. Honey bees are critical pollinators for many crops, and heavier hive losses will drive up the costs of both honey production and pollination services. The lack of effective and practical treatments for large-scale operations adds to the urgency of the situation. Current methods, such as caging the queen, are difficult to implement in commercial settings with thousands of hives. Furthermore, combining new treatments for tropi with existing ones for Varroa risks harming colonies or producing a dangerous new wave of chemical-resistant mites.
The story of Varroa shows how quickly a single parasite can transform global beekeeping. Tropi, with its faster spread and deadlier impact, has the potential to be even worse, making the search for effective management strategies a top global priority.