What Is Tracheal Mite? + Bonus Printable Guide

Image of a beekeeper inspecting a hive for tracheal mites

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.

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.


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.

A microscope image of the tracheal mite (Acarapis woodi)
Microscopic image of the Acarapis woodi.

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.
A honey bee's damaged tracheal system infested with tracheal mites
A honey bee’s damaged tracheal system infested with 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.


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.

Zoomed in microscope photograph of tracheal mite eggs within a honey bee's breathing tube
tracheal mite eggs within a honey bee’s breathing tube.

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.

A tracheal tube blocked by Acarapis woodi  mites and their eggs
A tracheal tube blocked by Acarapis woodi mites and their eggs.


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.

  1. 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.
  2. 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.
  3. After mating, females leave their host in search of a new bee. Male mites live their entire lives inside the same bee.
Acarine disease caused by eggs in the tracheal tube
Acarine disease caused by eggs in the tracheal tube.

Interesting research about tracheal mites

Toxicity of Seven Monoterpenoids to Tracheal Mites (Acari: Tarsonemidae) and Their Honey Bee (Hymenoptera: Apidae) Hosts When Applied as Fumigants.

Published in: Journal of Economic Entomology, Volume 90, Issue 5, 1 October 1997, Pages 1087–1091

Authors: Marion D. Ellis, Frederick P. Baxendale

Our summary: Lab tests were conducted to determine how harmful seven specific chemicals were to tracheal mites and the honey bees they live on. These chemicals were: citral, thymol, carvacrol, α-terpineol, pulegone, d-limonene, and menthol. They were used as gas treatments on bees that had mites.

Here’s what the researchers found:

  • Thymol and menthol hurt honey bees the most, while α-terpineol hurt them the least.
  • Menthol, citral, thymol, and carvacrol were more harmful to mites than bees.
  • Pulegone, d-limonene, and α-terpineol were more harmful to bees than mites.
  • Menthol was much more harmful to mites than bees at a specific concentration. But when the amount of menthol was increased, bees died faster than mites.
  • In tests with citral and thymol, mites always got affected more than bees. Citral and thymol were more harmful to mites at all tested amounts.

Read the research>

Molecular genetic analysis of tracheal mite resistance in honey bees.

Published in: Journal of Apicultural Research, 54:4, 314-320

Authors: A Lelania Bourgeois, José D Villa, Beth Holloway, Robert G Danka & Thomas E Rinderer (2015)

Our summary: Honey bees can resist the Acarapis woodi by cleaning themselves, a behavior called autogrooming (self-grooming). Bees use their legs to remove these mites before the pest gets inside their breathing tubes.

Scientists studied how specific genetic markers might relate to how much these mites affect a bee colony. They looked at a group of bees with mite-resistant and mite-sensitive parents. They found a specific part of the bee’s genes that might be linked to resistance against these mites.

Inside this gene area, three genes might affect how bees clean themselves. But the results weren’t clear when they tested this on a different group of bees. This means researchers can’t use these gene markers directly to pick mite-resistant bees.

Read the research>

Image attribution: Courtesy The Animal and Plant Health Agency (APHA), Crown Copyright”. Sourced from BeeBase Gallery.

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