Tropilaelaps mites: how to recognise a suspect and report it

Tropilaelaps mites are small, fast-moving parasites associated with honey bee brood. T. mercedesae has been reported in Russia, Georgia and Türkiye. If you find an unfamiliar narrow mite moving rapidly on the comb, leave the hive and equipment in place and contact the competent bee health authority.

This guide is for recognition and early reporting. In a region where the pest has not been reported, the first response is official investigation. Trials carried out in affected countries are background information, not a prescription for managing a suspect hive.

Field reference for recognising Tropilaelaps

Tropilaelaps Book: A la puerta de tu colmenar (Spanish edition)↗

Use the illustrated field reference to recognise a possible suspect. Confirmation and decisions on movement or control belong to the competent bee health authority.

What is Tropilaelaps?

Tropilaelaps is a genus of mites associated with Asian honey bees. Four species are recognised. T. clareae and T. mercedesae have also been reported on the western honey bee, Apis mellifera. The species in the recent westward reports is T. mercedesae.

Asian giant honey bees, including Apis dorsata and A. laboriosa, are its original hosts. They nest in the open on a single comb, migrate and abandon the nest when the parasite load is high, and all of that breaks the mite’s cycle from time to time. The western honey bee rears brood almost all year inside a box and has none of those escapes.

Older papers often used T. clareae more broadly. The revision by Anderson and Morgan in 2007 distinguished several species. Bear that in mind when comparing old records with reports of T. mercedesae.

Where has it been reported?

Long associated with southern and south-eastern Asia, the mite has also been documented farther west. Investigators reported it in north-eastern Türkiye in 2026. Türkiye subsequently notified the finding through the World Organisation for Animal Health.

It almost always travels with human help: the trade in queens, package bees and nuclei, migratory beekeeping and illegal trade. Follow restrictions on the movement and purchase of bees and hive material. Check official certificates, origin and the latest rules with your veterinary authority before any import or move.

Two recent findings explain why the old idea that it dies within two days without brood no longer holds. In July 2025 a swarm of Apis dorsata carrying 28 live mites was intercepted on a ship bound for the United States after at least 29 days without brood (Ramirez et al. 2026). And a 2026 study confirms that honey bee swarms also carry it from place to place (Uzunov et al. 2026). A quick look at the adults is not a health certificate.

How to distinguish it from Varroa

A much-quoted “25 times” figure comes from counts in Thai colonies, where up to 25 Tropilaelaps were found for every Varroa mite. It is a ratio in those colonies, not its rate of reproduction: each female leaves offspring similar to Varroa’s. Its advantage is that it spends very little time outside the brood and reproduces again almost at once.

A bee louse, Braula coeca, is a wingless fly with six legs, typically seen on an adult bee. A mite has eight legs as an adult. A clear image can help the inspector decide what needs confirmation.

Why the brood nest matters

The female enters the cell of a larva shortly before it is capped, around day 8 of worker development. Inside, she lays her eggs and her offspring feed on the pupa; when the bee emerges, the mother and her now adult daughters leave with it and quickly look for another cell about to be capped. This is one reason the brood may look abnormal while routine inspection of adult bees reveals little.

A beekeeper may first see scattered brood, damaged pupae or workers emerging abnormally. Keep a record of what you see and avoid moving frames between hives.

Two differences from Varroa change management. First, it cannot feed on adult bees, so on them it survives only a few days. Second, with open brood within reach, a female has lived for up to four weeks (Woyke 1994): a brood break that leaves open larvae does not clear it. What is known about survival off brood has changed in two years: on live adult bees it lasts several days, with a maximum of 6 described on honey bees; on dead pupae it reaches 7 days and on dead bees 8 (Gill et al. 2025); and in a swarm of its original host it survived more than 29 days. In practice, frames with dead brood, used equipment and captured swarms can carry it. Leave the assessment of suspect material to the competent authority.

Signs of injury in the colony

• A patchy brood pattern, empty cells mixed with healthy brood and injured or malformed pupae.
• Emerging workers may have deformed wings, shortened abdomens or damaged legs, weigh less and live shorter lives. The mite also transmits viruses, including deformed wing virus (Khongphinitbunjong et al. 2016). Similar signs occur with other bee health problems.
• Abnormal white pupae or brood remains removed by workers and found at the entrance or on the floor.
• A rapid loss of population and collapse if nothing is done. In untreated colonies in Thailand, worker brood infestation rose from 0.4% to 15% in 60 days (Tokach et al. 2024). Suspect it particularly when brood damage is more severe than the Varroa record would suggest.
• Severely affected colonies may dwindle or abandon the hive.

Several of these signs overlap with uncontrolled Varroa. Unexpected brood damage or a narrow, fast-moving mite is sufficient reason to call the bee health service. Laboratory confirmation establishes the diagnosis.

Would a Spanish winter rule it out?

Do not count on it. Tropilaelaps mercedesae has become established in areas with much harsher winters than Spain’s: northern China, Korea, southern Russia, Tyumen in western Siberia and Uzbekistan. And in much of Spain colonies are never completely broodless in winter, or only for a few weeks. With days of survival on adult bees and weeks if some open brood remains, a short break does not clear the colony. Climate alone cannot establish that an apiary or a shipment is free of the mite.

What is still not well understood is why it grows quickly in some apiaries and slowly in others. The first study of its population growth found very different rates and points to humidity as a factor to investigate (Aurell et al. 2026).

How a suspected infestation is investigated

Because almost all the mites are inside capped brood, that is where you look, and in worker brood: unlike Varroa, it does not prefer drone brood. Varroa methods on adult bees (alcohol wash, icing sugar or CO₂) collect very few: in Papua New Guinea, the alcohol wash found it in only 41% of infested colonies (Schouten et al. 2026). A negative result rules nothing out.

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1. Rapid decapping with a wax strip

This is the method used to confirm the Turkish outbreak (Uzunov et al. 2025). It works like this:

1. Choose a frame of capped worker brood at the white- to purple-eyed pupa stage (days 13 to 17 from egg laying), with more than 250 cells in a continuous patch.
2. Press a depilatory wax strip onto the cappings for about 10 seconds so that it sticks. If it is cold, warm it between your hands first.
3. Pull it off in one go.
4. Film the uncapped area with your phone held steady above it for 30 seconds.
5. Review the video and count the adult mites that come to the surface. Tropilaelaps runs and is easy to pick out.

It takes about 10 minutes per colony. In the study it detected more than 90% of infestations, and 94% of the uncapped brood survived. In a comparison of six methods in Papua New Guinea, a variant of this rapid decapping was the cheapest (Schouten et al. 2026). If you see a suspect mite, leave the frame in its hive, keep the video with the date and hive number and contact the bee health authority. A single negative check does not establish absence.

2. Bumping the frame over a white surface

Take out a frame with open larvae and brood about to be capped, shake off the bees and bump it hard against a white tray or sheet, twice on each side. Mites that were in the open cells fall and can be seen moving (Pettis et al. 2013). It is quick and, of the rapid methods, the one that detects it at the lowest infestation levels (Tokach et al. 2026). Even so, it misses many colonies: in Papua New Guinea it found it in only one in three infested colonies (Schouten et al. 2026). If something turns up, confirm it by uncapping; if nothing does, that rules nothing out.

3. Uncapping with a fork or tweezers

Lifting cappings with an uncapping fork and pulling out pupae one by one also works, but it is slow. Open large areas: the mites may be concentrated in one part of the comb and absent from another. If you find something, follow official instructions on any collection, handling and packaging.

4. Floor debris and monitoring boards

A sticky board under a screened floor collects the mites that drop, and the mesh stops the bees removing them. In a trial in Thailand it was the most sensitive method, ahead of uncapping and the bump test (Tokach et al. 2026). The drawback is that the mites are small and pale: the board has to be checked with a magnifier and good light, and it does not give an on-the-spot result as uncapping does.

Official surveillance programmes combine the board with an acaricide that makes the mites drop within 24 hours. In Papua New Guinea that found it in 92% of infested colonies, and environmental DNA swabs analysed in a laboratory found it in 100% (Schouten et al. 2026). These are diagnostic tools for the veterinary services, not treatments.

What to do if you suspect Tropilaelaps

Tropilaelaps infestation is notifiable in the EU. In Spain, reporting arrangements include Royal Decree 779/2023. If you see a possible case, take the following steps.

• Contact your autonomous community’s official veterinary service or local agricultural office promptly.
• Leave hives, combs and equipment at the site until the authority gives instructions.
• Keep photographs or video and record which hives you examined and when.
• Collect or send a sample only as instructed, using the designated route.

Early reporting gives the authorities the best opportunity to investigate and protect other apiaries. The official service decides movement restrictions and further action.

What do management studies show?

Research on brood interruption

Without brood the mite cannot reproduce and dies within a few days. In Chiang Mai (Thailand) the queen was caged for 24 days and, after 60 days, worker brood had less than 0.11% infestation, against 15% in untreated colonies (Tokach et al. 2024). Making up a nucleus with the queen also reduced the mites in both the parent colony and the nucleus (Pettis et al. 2017). None of this establishes a universal eradication procedure.

Two details matter. The break must last until no brood is left, open or capped: after 14 days with the queen caged there is still brood to emerge. And the break clears Tropilaelaps but not Varroa, which survives on adult bees. In an apiary with both mites, the brood break is the moment to apply the authorised Varroa treatment.

Besides caging the queen, there is another way to stop brood rearing: ringing her. A small plastic ring is fitted round her abdomen so that she cannot bend it to lay, while she still moves freely about the hive. In a 2024 trial, ringing stopped brood rearing as well as caging did, with no difference in colony strength, although after the rings were removed one queen was lost and another was found alongside a daughter queen (Uzunov et al. 2024). It was tested with Varroa in mind; with Tropilaelaps the logic is the same: without brood, it has nowhere to reproduce.

What does not help here is removing drone brood, which does help against Varroa: Tropilaelaps mainly enters worker brood (Buawangpong et al. 2015).

Research on medicines and other interventions

In northern Thailand, of the products tested, formic acid was the only one that reduced the mites at 8 weeks without side effects. Powdered sulphur also reduced them but weakened the colonies; hop extract weakened them, and amitraz strips had no effect (Pettis et al. 2017). Combined with a brood break, formic acid left the brood with no detectable mites but the colonies somewhat weaker; oxalic acid added nothing to the break (Tokach et al. 2024). Those results do not provide a treatment authorisation for a Spanish apiary.

The synthetic acaricides used against Varroa are not a fallback either. In a laboratory trial with mites from colonies in Chiang Mai, coumaphos, flumethrin and fluvalinate did not reach 50% efficacy and amitraz reached 64% (Gill et al. 2024, preprint not peer reviewed). In the hive its biology adds to the problem: those products act on mites carried by adult bees, and Tropilaelaps spends very little time off the brood. An unapproved substitution can delay diagnosis and appropriate measures.

Heat has also been tested. In central Thailand, heating hives with heating blankets cut Tropilaelaps by 85% in three weeks, more slowly than formic acid, which kept it close to zero, and with a rebound of mites in the second week (Sankovitz et al. 2025).

In an area without confirmed establishment, surveillance, early reporting and compliance with movement controls remain the immediate priorities.

What a beekeeper in Spain can do now

• Buy bees only from traceable, permitted sources and retain their health and movement documentation. Check restrictions with the competent authority before ordering.
• When you receive a queen, move her to a new cage with bees from your own apiary and destroy the accompanying workers and the shipping cage. The Spanish agriculture ministry has a protocol for separating them.
• Captured swarms: if you can, house them away from your apiary and, once they have brood at the pupal stage (about three weeks later), check the brood with a wax strip.
• Avoid accepting used material with an uncertain health history. Keep comb from dead or suspect colonies out of the common equipment stream.
• Never exchange or move frames when a pest or disease is suspected.
• Learn to read the brood: a wax strip on two or three colonies per apiary when you do your Varroa counts costs little and shows you what normal brood looks like. It is easier to spot an unfamiliar pattern when you have dated records from normal inspections.
• Maggie Gill, Aleksandar Uzunov, Irakli Janashia and Marin Kovačić, who wrote several of the studies cited here, explain how to recognise it and look for it in Tropilaelaps. A la puerta de tu colmenar, a full-colour manual that we distribute in Spanish. An inspector or laboratory confirms a suspect finding.

Frequently asked questions

Sources and surveillance references

• Özkırım and colleagues (2026), report on the first finding in Türkiye. The cited version is a preprint.
• Apimondia’s statement on Tropilaelaps in Europe, 16 October 2026.
• Franco, Duquesne and Laurent (2025), EU Reference Laboratory note on geographical spread.
• Brandorf and colleagues (2024), report of established populations in European Russia.
• Janashia and colleagues (2024), first report in Georgia.
• Ramirez and colleagues (2026), pest interception in an incoming shipment.
• The EU Reference Laboratory’s beekeeper leaflet summarises official prevention and reporting guidance.
• Uzunov and colleagues (2025), scientific note on rapid brood examination.
• Tokach and colleagues (2026), comparison of monitoring sensitivity.
• Schouten and colleagues (2026), field assessment of early detection methods.
• Buawangpong and colleagues (2015), prevalence and reproduction of Tropilaelaps mercedesae and Varroa destructor in colonies infested with both mites.
• Woyke (1994), survival of Tropilaelaps females for four weeks with open brood.
• Gill and colleagues (2025), survival of Tropilaelaps mercedesae on different substrates.
• Uzunov and colleagues (2026), swarming and the dispersal of Tropilaelaps mercedesae.
• Aurell and colleagues (2026), first estimates of Tropilaelaps mercedesae population growth. The cited version is a preprint.
• Tokach and colleagues (2024), field study of cultural and chemical management.
• Pettis, Rose and Chaimanee (2017), management approaches in northern Thailand.
• Gill and colleagues (2024), laboratory study of acaricide susceptibility, cited as a preprint.
• Sankovitz and colleagues (2025), field comparison of management approaches.
• Uzunov and colleagues (2024), comparative study of queen management.
• Pettis and colleagues (2013), survey methods for detecting Tropilaelaps.
• Khongphinitbunjong and colleagues (2016), effects on worker condition and longevity.
• Anderson and Morgan (2007), taxonomic revision of Tropilaelaps.
• WOAH Terrestrial Manual, chapter 3.2.6, infestation of honey bees with Tropilaelaps species.
• de Guzman and colleagues (2017), review of Tropilaelaps and bee health management.
• Spanish agriculture ministry guidance on queen consignments.

Further reading

• Varroa destructor: recognising and managing the mite
• Monitoring Varroa and interpreting results
• An integrated Varroa management plan
• What to do about a swarm of honey bees

Updated for the November 2026 edition. The geographical situation can change. If you suspect a case, the current instructions of the competent veterinary authority take precedence.