Tracheal Invaders

In 1922 the Honey Bee Act was passed by Congress to prevent the importing of live, mite infested honey bees into the United States. Yes, a congressional act, on honey bees. This is serious stuff. The reason behind this act was due to the Tracheal mite (Acarapis woodi) that was reported in 1921 on the Wight Isle of the English Channel. Today, the act helps to prevent against other mites and numerous exotic species that can be detrimental to the honey bee as well. The hopes of keeping Tracheal mites at bay were decimated in July of 1984 when they were found in a commercial beekeeping operation in Texas.  Within 13 months Tracheal mites were found in 17 states across the US. The rapid spread is believed to be attributed to sale of queens, nuc colonies, packaged bees, and migratory beekeepers.

Unlike the Varroa mite, which is relatively easy to view with the naked human eye, Tracheal mites oval bodies are around 125-174 microns in length. Their minute size makes viewing them without a microscope impossible. Hence the reason the mite is difficult to detect and often infestation is not realized until the levels are very high.

Tracheal Mites in the tracheal tubes of the honey bee. Photo credit: MAAREC 2000

Tracheal mites primarily spend their life cycle in the tracheal tubes of honey bees but can also be found in air sacs and in the thorax and abdomen. They feed on blood, penetrating through the tracheal tube walls, deteriorating, discoloring and producing crust-like lesions on breathing tubes, causing them to become stiff and brittle. In early stages, the bees are unaffected and infestation levels lower if the colony is actively foraging. In addition, worker bees are much less susceptible to the mites as they mature. Usually Tracheal mites infest honey bees nine days and younger through bee to bee transmission. When a bee dies the mite climbs to the tip of the bee’s body hair and is transferred from one bee to the next. Bees who fly between apiaries or hives carry the mites, however the mite will die if it fails to find a host within 24 hours.

The most common period for signs of infestation is winter and spring. If left untreated, Tracheal mites can cause colony death if  infestation over 30 percent is present. Levels below this shorten bee life cycle, affect flight efficiency, and can cause Deformed Wing Virus. Unlike many bee viruses making their way across the world today, there is hope when treating the Tracheal mite. The most common treatment used today is menthol crystals, which is a crystalline alcohol extracted from peppermint oil.

Despite the  Honey Bee Act of 1922,  Tracheal mites still managed to find their way into the United States, although the act may have delayed the invasion of

Adult Tracheal Mite. Photo credit: Beekeeping for Dummies

the mites on US soil. The rapid spread of the tracheal mite across the country shows just how high the mobility of pests and pathogens to beekeeping  within the US really is. While we hope to keep other invasive species out of the US, a congressional act can only do so much to keep the livelihoods of our bees safe. What we must do is have a course of action in place in anticipation for the worst. If other invasive species cross our borders how will we handle it? How will we mobilize beekeepers across the country to take action to protect their bees? While the plaguing question is one that has haunted beekeepers for years, one thing is for certain, we must take action before it is too late to prevent and guard against other invaders.

Written By: Jennie Stitzinger

Jennie Stitzinger has written 55 post in this blog.

In the summer of 2010 I walked in to the Penn State Agricultural Sciences building to inquire about a job a friend had mentioned to me. I was a poor college student, I needed to pay my summer rent, I was offered the job and I took it—I had no idea what I was in for. Fast forward a little over a year and I was kneeling on rocks and mud, in the cold, northern California rain, surrounded by dairy cows and hundreds of hives while Africanized bees were pinging off my bee suit. With a degree in Community Development from Penn State University, I never thought in a million years I would be working with honey bees upon graduation, but I guess life sure has its surprises. Now a member of the University of Maryland Diagnostic team, I work on many different aspects of BIP and the National Honey Bee Survey. Whether it is field work, traveling, report writing, crunch time projects, or larger missions, I am most likely working on it. What is my favorite part of the job? Working on an awesome project that has impact and is helping beekeepers around the country, learning more about honey bees than I ever thought I wanted to know, and giving me experiences I never thought possible.