Table of contents
Considering they have only stubby little legs—and no wings, fins, or driver’s licenses—varroa mites have no trouble getting around. Varroa mites have many routes of transmission. In fact, they have an entire public transport system built and maintained by the very host they parasitize. Seems unfair, doesn’t it?
While many routes of transmission from colony to colony have been documented, some are more important than others. Here’s a list of common ways mites get around, and there could be others.
1. Mites on flowers
Of all the possible methods of mite transmission, this one seems the least likely. Mites are attracted to the pheromones of bees, so it seems far-fetched that a mite would jump off a bee onto a flower and wait for another bee to arrive.
However, if a varroa-laden bee lands on a flower and begins to groom, it is possible that she will dislodge a mite. If so, that mite has no choice but to wait for another honey bee to come along and give her a lift. Surely this happens from time to time, but it’s probably not a major means of transmission.
2. Beekeeper assistance
Beekeepers can easily move mites between colonies when they exchange frames of bees or brood between hives or when they make splits. If they have outyards and move their bees between yards, the spread of mites can be faster.
3. Drifting worker bees
Not all honey bees make it back to their own colony. It is well known that if you have a row of hives, the hives on the ends will slowly gain population while the ones in the middle lose it. These bees are the drifters.
If these lost bees are carrying pollen, nectar, or other needed stores, they are usually welcomed into the new colony. The unseen gift, though, could be phoretic mites tucked between the bee’s segments which are happy to jump off and make themselves at home.
4. Wandering drones
Unlike foragers, drones are not too particular about where they spend the night. Drones are very likely to stop in at any old colony and the foragers usually let them in. Wandering drones are often considered to be a major mode of varroa mite transmission.
5. Swarming bees
If a colony has mites, so will the swarm that comes from it. It only takes one mite to begin a new infestation.
6. Absconding bees
Bees don’t always abscond in massive groups like a swarm but may leave a hive in onesies and twosies. This can happen when:
- a colony is collapsing from disease or parasitism
- when the bees are starving
- when a colony remains queenless for a long period
- when a colony is decimated by bears or other predators
- after a fire or flood
- whenever the bees’ home is destroyed or becomes uninhabitable
The bees fly off and some may be lucky enough to find another colony to join, carrying with them their trove of mites and/or other diseases.
7. Robbing bees
Whenever a bee colony becomes weak it is a potential target. Bees from healthy robust hives are often eager to empty out the pantry of a weaker hive and ferry the treasure back home, a form of kleptoparasitism that is greater in some races of honey bees than others.
Oftentimes the weak hive is riddled with varroa mites, and it may even be collapsing for that reason. The robbing bees end up with more than they bargained for, taking home both honey and a blood-thirsty population of varroa mites. Aha! What do they say about greed?
Varroa mite transmission is a never-ending problem
The take-home message is that your colony can pick up an infestation of varroa at nearly any time of the year. The best practice is to monitor your hives regularly to see if you have a problem, and then decide on a course of action if you do.
Rusty
Honey Bee Suite
Do you subscribe to the idea that swarm management may be contributing to mite growth by discouraging and prohibiting swarms? Do you need me to elaborate on the idea? TonyG
Tony,
1. Preliminary data show that more frequent swarming, less brood production, and smaller nest cavities may render European honey bees less vulnerable to Varroa destructor and related viruses. Whether that is a viable solution for urban and suburban beekeepers is a separate question.
2. No.
Do bumble bees and other types of bees other than honey bees get varroa mites?
Myrna,
To my knowledge only Apis cerana and Apis mellifera get varroa mites. However, there are zillions of different kinds of mites, many of which affect other bee species. The mite’s life cycle must be closely tailored to the host bee’s life cycle. Somewhere on this site is a photo of a bumble bee with mites and a mason bee with mites.
Very interesting and helpful post. I got to wondering how varroa mites reproduce if it only takes one to begin a new infestation. Clever little critters!
Pennie,
Varroa mites mate before they leave the brood cell where they were born. While still inside the capped brood cell, the female mites mate with their brother mites. So when a female emerges from the honey bee brood cell, she is fertile and ready to lay eggs, which is why it only requires one to start a new infestation.
No threat of varroa mites to apis cerana.
Binish,
Well, they certainly have varroa mites, but since they co-evolved they are able to co-exist.
hello sir,
I have two questions
1. During a split what happens if more than one queen is raised
2. How many swarms can be from a single hive do they equals the number of swarm cells.
Muzafar,
Not sir, thank you.
1. The strongest queen will kill the others.
2. The number of swarms depends on many factors. There may be just one, or it may go up to three or four in one season, but it has nothing to do with the number of swarm cells.
Thanks for posting this.
Interested discussion going on reddit about Treatment Free options to encourage healthy bee genetics.
One option I haven’t heard discussed as much is Treating for Resistance, which seems to offer the best of both worlds (treats to reduce mite-load in the area, but doesn’t prop up poor genetics).
Detailed description here: https://www.reddit.com/r/Beekeeping/comments/4hwnvr/to_best_breed_healthy_bee_genetics_dont_go/
What do you think?
Mr Temple,
Sounds like doublespeak to me. He keeps talking about getting bees from this thriving, resistant colony but doesn’t explain how everyone is going to find (or evaluate) one of those, or how one is supposed to control for resistant drones.
I would be interested in hearing more, Tony
Hello Rusty,
I did split few days ago, today I saw one queen emerged which is looking small in size there are still fee queen cells there what should I do?
Muzafar,
You can put that emerged queen in a cage so she can’t injure the others, and then wait till the others emerge to see what they look like. Just a piece of hardware cloth rolled in a cylinder will work for a cage, and the workers will tend to her through the wire.
Remember that queens don’t reach their full size until after they mate. They often look quite small at first.
Rusty,
I’m confused with the varroa reproduction. I understand that if only 1 female enters the cell, then she will have 1 male and up to 3 females (that have a chance to mature before the bee). The females mate with the male, being incestuously fertilized. In other species this leads to rapid degradation of the gene pool and is typically followed by collapse of the species. How and why are varroa immune to this effect?
Adam,
Such a good question and I don’t know the answer. I will have to do some research.
Rusty,
I have been wondering about this ever since I first learned how Varroa mites reproduce. If you have found the answer, I would love to hear it.
Thank you so much for sharing your experience and knowledge. I love your blog and these days I spend more time on it than on any other site. Please keep it up.
Rusty,
I am new to beekeeping and I have a problem that I am not sure how to solve. When i installed my bees, I couldn’t get the last frame in the hive without squishing the bees, so I left it out. Because bees are super productive, they built their own frame in that space, attached to the inner cover. Do you have any suggestions on what I should do with this frame?
Thank you for your help!
Ashley,
Cut the comb off the inner cover and then, using string or rubber bands, tie it into an empty frame. Or if it doesn’t contain larvae, you can just save it for candles. Put all your frames in the box or, if you still want to leave one out, space the others evenly across the box. Don’t leave a big space.
Rusty,
Thank you so much!
Hi Rusty,
May I use your post for my association’s newsletter? Varroa and IPM has been a frequent topic and this would be a great info addition.
Thanks,
Laura
Laura,
Yes. Just give me a link/credit.
Will do! Thanks
Hi Rusty,
I am wondering how long mites live in a dead out?
If I have a dead out from the winter, let’s set aside the why for now and say it lost the queen late fall and was dead in the spring with at least 2 months of no bees live in the house. If I put in a package or catch a swarm or drop in a shook swarm, will there be enough live mites to reinfest, or is the 8 week break enough to starve the mites out as well? I would like to reuse the combs as they are only one year old and have a fair amount of pollen and honey in them. I do see a bit of the white mite poop and am thinking that the old hive did have some mites.
BeeHappy,
Varroa mites are totally dependent on honey bees for survival. I’ve seen different estimates on how long the mites can live without bees, but it varies from a few hours to a few days.
Thanks for the response. I was going to toss the frames away and thought what a waste, bad enough the bees are gone. The pollen and honey would be a great start for a package.
I’ve searched your site and haven’t been able to reference going “broodless” by caging the queen for 2 weeks. The purpose of this is to break up the mite cycle a bit. Then you only contend with mites on the bees and not those in the brood that are harder to get.
Kelsey,
For a complete brood break the colony must go eggless for 27 days. See https://www.honeybeesuite.com/booklet-review-splits-and-varroa/
Thanks so much. I bought the book immediately after reading your post. I want to do minimal treatments. My goal is healthy bees then honey/wax.
They have found varroa mites on some wasp larvae and some bumble bee larvae according to research, check out Wikipedia regarding the uninvited varroa mite from Asia.