Tropilaelaps mites are honeybee parasites that share some similarities with varroa mites. The primary hosts of tropilaelaps are some of the Asian honey bee subspecies (Apis dorsata and Apis laboriosa). However, like varroa, some tropilaelaps species have more recently adapted to parasitising the European honey bee (Apis mellifera). 

Tropilaelaps mites are currently largely confined to Asian countries such as the Philippines, Thailand, Vietnam, India, Sri Lanka, Afghanistan and Pakistan. Their geographic range has spread rapidly within the last 50 years and they have been reported in Kenya and Papua New Guinea. There is great concern that they will cause enormous damage to honeybee colonies in any area that they spread to.

Tropilaelaps adults lay their eggs inside honeybee brood cells and the developing mite larvae feed on the blood of the developing bees.

Tropilaelapsmites appear similar to varroa mites, though they are significantly smaller and their bodies are more elongated. They are brownish-red in colour and have hard-shelled bodies. Females are approximately 0.7mm long and 0.5-0.6mm wide, while males are significantly smaller.

Diagram of adult tropilaelaps mite

Tropilaelaps and varroa mites cause similar damage to European honeybee colonies. They can kill the developing brood, shorten the lifespan of adult bees that survive the brood stage and spread diseases such as deformed wing virus. These mites have caused significant losses to honeybee colonies across Asia. European honeybees are more susceptible to damage from tropilaelaps than Asian honeybees because they have not evolved the same behavioural defences against the mites.

Tropilaelaps have a similar life cycle to that of varroa mites, but have a shorter lifecycle, which enables them to build up much faster within a colony. The mites reproduce within brood cells, with a female mite typically laying 3-4 eggs daily onto bee larvae, beginning 48 hours after the cell is capped. Both the adult and developing mites feed on the haemolymph (blood) of the bee larvae.

Tropilaelapsmites spread most rapidly through beekeepers transporting infected colonies. They can spread within apiaries through contaminated equipment and combs. Tropilaelaps mites can also spread over long distances via adult bees through drifting, robbing and swarming. 

Signs of tropilaelaps infestation are similar to those of varroa. High brood mortality, irregular brood pattern, perforated cappings, stunted adult bees and bees with deformed wings are potential indicators of tropilaelaps.

Tropilaelaps mites can be detected using the sugar shake, alcohol wash or sticky board method. Tropilaelaps can be distinguished from varroa mites, as they are smaller and narrower than varroa. 

Tropilaelaps mites on European honey bee brood

Maintaining good hygiene and husbandry practices will help to prevent the further spread of these mites. Be aware of local regulations regarding pest monitoring and reporting. If you suspect that you have tropilaelaps mites in your apiary, contact the regulatory authorities immediately. Rapid detection and identification can help to keep this parasite out of countries where it is not yet established. 

Providing a brood break is an effective treatment against tropilaelaps, as the mites cannot survive for long outside of the brood cells. Beekeepers in areas where tropilaelaps is present may treat their hives with acaricides very frequently. If the mites are detected in a new country, an eradication or containment plan will be implemented to try to control the outbreak.