What Is Tracheal Mite? + Bonus Printable Guide
The tracheal mite (Acarapis woodi) is a microscopic parasite that infests honey bee colonies. It targets the tracheae or breathing tubes of the bee to develop, feed, and reproduce.
Infestations can severely impede the bee’s ability to feed and respire. They lead to weakened colonies, decreased honey production, and the collapse of entire hives in severe cases.
This guide helps beekeepers understand the symptoms, prevention, and treatment of tracheal mites.
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Quick facts about tracheal mites
- Unknown until the 1920s, they were initially found in the Isle of Wight.
- This pest reached the United States around 1984.
- Brother Adam developed Buckfast bees in response to these mites.
- Tracheal mites are also known as acarine mites.
- The mite lives in most countries globally.
- These mites use the bee’s smell (cuticular hydrocarbons) to find young bees to live off.
- Mites die within 24 hours if they fail to find a bee to live in.
Appearance
The tracheal mite is microscopic, making it challenging to see without specialized equipment like a microscope. Females measure 140 to 175 microns in length, while males are 125 to 136 microns. That’s not much longer than the diameter of a human hair.
The body of the tracheal mite is egg-shaped and a semi-glossy white color. It is wingless and lacks eyes but has three pairs of legs. The first set near the head is adapted to grasp the honey bee.
Symptoms of tracheal mites in a hive
The signs of tracheal mites are often difficult to recognize as symptoms are not unique to tracheal mites. Beekeepers usually notice them in fall and winter, when they peak.
Some common symptoms include:
- Bees crawling outside: One of the most noticeable signs is bees wandering on the ground or at the hive’s entrance.
- Disoriented behavior: Infested bees often display abnormal behavior, seeming disoriented, lethargic, and aimless.
- Unusual clustering: Bees may not cluster on cold days, instead forming disorganized patterns.
- Disjointed Wings (K-Wing): Tracheal mites may cause the bee’s humuli, which joins the pairs of wings, to become disjointed. Instead, the wings project at a 90-degree angle from the body’s axis.
- Dysentery: Bees exhibiting signs of dysentery may have tracheal mites.
To reduce guesswork, collect a sample of 50-100 bees in a jar with alcohol. Send them to a local county identification office to have them tested under a scientific microscope.
Prevention
Proactive beekeepers can take steps to keep their hives free from tracheal mites. Regular inspections during summer and fall and maintaining clean tools and equipment will reduce the spread.
Some strains of honey bee breeds have excellent resistance to tracheal mites. Buckfast bees were bred specifically to cope with this pest. Other strains, such as Russians and Carniolans, are also fastidious housekeepers. They swiftly deal with mite infestations.
Before introducing new colonies to an apiary, quarantine and monitor them for signs of mites.
Also read:
What are braula flies?
A guide to treating varroa mites.
How does tracheal mite spread?
Female tracheal mites eventually leave the honey bee they developed in. They exit through the thoracic spiracle and transfer to a nearby healthy bee by clasping onto its hairs. In the right conditions, tracheal mites spread quickly within the hive.
While some pests like SHB fly to new hives, tracheal mites are wingless. They rely on bees to help them spread to uninfected colonies. Drifting, swarming, and robbing bees are significant causes of distribution. Standard beekeeping practices like offering pollination services, splits, and combining hives also contribute to the problem.
Interesting reading: Lifecycle of the small hive beetle.
Treatment
Treating tracheal mites is one of the easier honey bee pests to control. Some popular, safe treatments include:
1. Menthol
Menthol pellets are an effective and commonly used treatment. Place them on top of the frames, following the manufacturer’s instructions. The menthol vaporizes as the temperature rises, causing the fumes to eradicate the adult mites.
As menthol does not affect mite eggs or larvae, it should typically remain in the hive for around two weeks.
- Always wear goggles and protective gloves during application.
- The pellets are similar to cough drops but more concentrated.
- There are minimal side effects on honey bees if used correctly.
- Never use on colonies during honey flow.
- Place menthol on the bottom board in warmer weather, 79°F (26°C).
- Place menthol on top of frames when temperatures aren’t higher than 60°F (15°C).
2. Grease patties
Grease patties are a simple and effective way to get rid of tracheal mites. Bees get oil on their body which impedes the mite’s ability to spread.
Mix one part solid or liquid vegetable oil with 2-3 parts granulated sugar. Form a flat burger patty shape, then place one on the center of the frames on wax paper.
Tip: Add a natural extract like spearmint or lemongrass to the patties for quicker results. The fragrance will help attract the bees to the cakes.
3. Essential oils
Research has shown that some essential oils, like thymol, will manage mite levels. If applied correctly, this approach won’t harm honey bees and is effective against Acarapis woodi and Varroa destructor. Review the research here>
Lifecycle of a tracheal mite
The lifecycle of the Acarapis woodi takes around 15-20 days, from egg to adult. Its development occurs within the breathing tubes (tracheae) of adult bees. The mites live in any bee caste: worker bees, drones, or the queen.
- Female mites typically lay 5-7 eggs within four days of entering the bee. They continue to lay eggs for the duration of their life. The eggs hatch within 3-4 days.
- Larvae hatch from the egg and go through a resting stage before reaching adulthood. The female mite takes 14-15 days to mature, while the male takes 11-12 days.
- After mating, females leave their host in search of a new bee. Male mites live their entire lives inside the same bee.
Interesting research about tracheal mites
Image attribution: Courtesy The Animal and Plant Health Agency (APHA), Crown Copyright”. Sourced from BeeBase Gallery.