Braula coeca: devastating bee parasite makes a lousy companion

It turns out I’m not the first person to misidentify a bee louse. Bee lice are imports from Europe and they live in honey bee colonies. They are insects and so have six legs, unlike the Varroa mite which is an arachnid possessing eight legs. The bee louse, Braula coeca, is actually a small wingless reddish brown fly less than 1.5 mm in length. They are considered to have only a minor impact on colonies, so little attention is paid to them.

The adults are commonly found on the heads of honey bees where they seek bits of food as it is transferred between bees. Generally, workers carry only one mite, but drones may have more, and queens may have many. According to the University of Florida, a single queen has been found to carry 180 lice at one time.

The adult female may lay her eggs in many different places within a hive, but in order to hatch, the eggs must be placed on top of honey cappings. After hatching, the larvae tunnel under the cappings, eat wax and pollen, and leave a visible trail.

It turns out that many Varroa control products also kill bee lice, so they are most often found in hives that have not been treated for Varroa.

In the photos below from the University of Florida website, you can see a comparison of an adult bee-louse on the left and an adult Varroa mite on the right.


Braula coeca
On the left, with six legs, is the adult bee louse, Braula coeca. Photo © University of Florida. On the right, with eight legs, is the adult Varroa mite, Varroa destructor. Photo © Scott Bauer, USDA.


  • I liked your caption – “On the left, with sex legs, is the adult bee louse, Braula coeca.” Sexy legs is not the first description that would come to my mind, but then beauty is in the eye of the beholder!

    I had to study Braula coeca as part of my British Beekeeping Association pests and diseases exam, though as I use varroa treatments I don’t expect to ever see it in my hives. I did a revision post on it at

    • Emily,

      Did I mention they were all doing the can-can?

      I read your post. Excellent. I could have saved myself a lot of time by reading it before I worked on mine! My only quibble was where you wrote “pronounced Browler Seeker.” In England, maybe. Here in the states we’d say “Browla Seeka.” It’s what flips me out when I listen to the BBC News. I always wonder where you all find the extra Rs. We have a shortage, especially in the eastern U.S. where they have “wata” coming out of their taps. Maybe we could come to a trade agreement?

      • When I went to California I kept asking for ‘water’, to be met by looks of bafflement. Often my American friends had to translate. Eventually I gave up and imitated their pronunciation of ‘wata’, it made life easier!

  • Do bees that are resistant to Varroa (sanitary gene/grooming behavior) also remove the louses? Or is it something I need to look for. My bees are all from a line of resistant bees and I have never seen a varroa.

    • Joe,

      I do not know how hygienic behavior affects bee lice, but apparently they are not something we need to worry about.

  • “On the left, with sex legs, is the adult bee louse,”

    Made for fun reading. But I counted those teeny tiny legs – yup, 6
    legs. I’m no judge, but I’m not finding them sexy.

  • The BBC doesn’t speak for all Brits. I think you’ll find that in many places here in England, the term for the wet stuff is ‘Wawa’

  • I have 6 hives just this year. I have noticed that 4 of them have lice quite heavily. One has a few less and one has very few. Now this is what I have noticed. The hive with a lot of lice have NO varroa. The one with less lice has a few varroa. And the one with few lice has quite a few varroa. I also noticed that on my screen bottom board covers the lice were agitating the varroa on the board. I was wondering if anyone else has noticed anything similar. I know for sure my bees drift the hives are only 5.5″ apart, I have 1 black queen but there are black bees in every hive. Could the lice be irritating the varroa off the bees? I do not understand why the varroa would not be the same percentage in every hive.

    • Robert,

      I don’t know anything about the interrelationship between bee lice and varroa mites. However, if your bees are drifting as you say (and most do) I strongly suspect varroa in all of them. How did you test for mites to determine relative infestation? If you are simply looking at natural mite drop, the colonies without a lot of capped brood probably will drop more mites on the board since a larger proportion are phoretic. I’m not sure it has anything to do with bee lice.

      • They all have capped brood but the 2 that I am comparing to each other are about the same size colonies. They have 3 hives in between them. I am using a sticky board under a screened bottom board. They are both 2 deep boxes 3/4 full of bees. 4 Days ago I did a 24-hr mite count and there were 15 mites in one box and 0 in the other. Yesterday I did another 24-hr mite count after putting wintergreen salt grease patties in and there are 30 mites in the one and only 1 in the other. I am taking a close up photo with a good camera and counting them on my computer to be as accurate as I can. The one that had A LOT of lice is the one that had only 1 varroa. It could be a simple coincidence or the lice irritate the mites out of the box? Monday or Tuesday this next week I will be treating all 6 with APIGUARD for the full 4 weeks. And because I am not pulling any honey this year I am not concerned about that part. I was just wondering if anyone has noticed if they had a lot of lice how their mite counts were. And I know that some people think the lice are mites and treat for mites and take care of the lice also. So they would not see any relationship between the 2.

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