I talked about Varroa Mites yesterday, and I wanted to point out that solitary bees also have parasites that can be deadly.  Osmia, or Mason bees, occur in all shapes and sizes, but nearly all 300 species are fuzzy, mild-mannered, and adorable.  They’re called mason bees because they create nest chambers out of mud.  Each individual female does all the work herself, unlike social bumble bees and honey bees.

Sadly, just as lots of things like to kill honey bees, there is also an extensive list of predators, parasitoids, and parasites that specialize on just this one type of bee.

Solitary bees pose a unique challenge for a parasite. How are you supposed to build up a population when your host doesn’t live in a group or a herd?  Somehow you have to spread and move between both individuals and generations.

One time when even solitary animals have to hook up is…. when they hook up.  Parasitic mites on bees hop off one host and onto another just like changing taxis. The bees are too otherwise occupied with gettin’ it on to notice.

I posted some footage of varroa mites on honeybees yesterday, but that pales in comparison to the horror I’m about to show you.   Indeed, I hope it will shock you, make you quite itchy, and put you off sex for a while.  (I’m not getting any, so might as well make it a universal condition.)

From the video author:

“These Red Mason Bees are heavily (probably fatally) infested with mites. Mites will often move from the male bee (who picks them up whilst visiting flowers), to the female during copulation. The female will then carry them to her nest where they will feed on the provisions and breed. Mites often will suck the blood of bees, sometimes leading to death. Heavily infested bees are unable to fly.”

The mites are probably Chaetodactylus osmiae, but that’s a guess.

Miloje KRUNIĆ, Ljubiša STANISAVLJEVIĆ, Mauro PINZAUTI, & Antonio FELICIOLI (2005). The accompanying fauna of Osmia cornuta and Osmia rufa
and effective measures of protection Bulletin of Insectology, 58 (2), 141-152

Posted by Gwen Pearson

Writer. Nerd. Insect Evangelist. Have you heard the good news? BUGS!


  1. These particular mites are most likely Chaetodactylus osmiae (a pest in Europe) a kleptoparasite that ‘steals’ the pollen in the bee cells. We have C. krombeini on the Blue Mason Bee in North America and no doubt lots of other species that no one pays much attention to because they are on bees we do not herd. Climbing onto a male bee is a dumb thing to do for a mite unless they can transfer during copulation. I hope they know how to discriminate between sexy and dud male bees.

    Chaetodactylus have two other methods of infesting the Osmia. The first is a simple function of the nesting style of the bee – a series of longitudinal cells in a tunnel in a log (or nest box). To exit, each new bee has to travel through the cells of bees more towards the exit and can pick up new mites (one wonders if there is a correlation between exit rank and mite load). The second is more insidious, but again takes advantage of bee behaviour. A sedentary morph of the heteromorphic deutonymph (the non-feeding, phoretic stage on the bees) sits around the burrow or nest until a new bee comes to reuse the old nest hole. The mite life cycle is pretty fascinating with alternation between parthenogenetic and sexual reproduction and a host of other interesting interactions.

  2. I read that bumble bees can be infested with mites. These mites do not feed directly on the bumble bee but on the wax and pollen in their nests. Never the less a heavy infestation would surely be an encumbrance. The Bumble Bee Conservation Trust suggests trying to brush off the mites. Here the mind boggles. However, watching the video I did wish I could just brush off the mites. Goodness, they were even on the eyes!

  3. Actually, bumble bees have quite a variety of mites and not all of them are known to be kleptoparasites. Some are potentially mutualists – predators that feed on the pollen-thieves, for example, so I’d suggest leaving mitey bumble bees alone. Trying to brush the mites off would be a bit ticklish and could easily harm the bee either directly or indirectly through removing good mites.

  4. I have never heard of the mutualists, it seems to be a real bug eats bug world, but if their is a niche out there it will be filled.

  5. We tend to assume the worst about an unknown bug, but if you think about it, many interactions, even if they seem rather negative at first, are mutually beneficial. So, many insects steal pollen from flowers, but often give the plants such a good time that they make more plants. Most vascular plants have fungi that infest their roots and steal carbohydrates, but these mycorrhizal associations benefit the plants by collecting and sharing nutrients more efficiently than the plant roots. Termite and cattle guts are full of microbes, but without them the animals would starve. Burying beetles are covered with mites, but most are predators on flies and nematodes that would compete with the burying beetle babies for food. And so on … As well as numerous parasitic species, many bees and wasps have mites that benefit them. So much so, that often the hymenopterons have specialized pouches called acarinaria – sort of executive lounges for mites to hang out in during flights from one nest to another. Unfortunately, most of these interaction are not well studied – and since we don’t understand them, it is best not to interfere with them until we do.

  6. Commensal interactions with mites and acarinaria are completely new to me and as you say these interactions are not well studied. You are right what we do not understand we should leave alone.

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