Like having a gerbil attached to your knee...

While photographing a Lasius alienus colony in the park yesterday I noticed a red, round mite hanging off the leg of this worker ant. I'm glad we humans don't have parasites like these.

Perhaps if we're really nice, Macromite will tell us something about the little guy.

Photo details: Canon MP-E 65mm 1-5x macro lens on a Canon EOS 50D

ISO 100, f13, 1/250 sec, diffused flash heads positioned for backlighting and fill

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Looks like an Oplitis sp. (currently in Uropodidae or Trachyuropodidae or Oplitidae, depending on how strongly you feel about [or understand] paraphyly). They are subcircular in outline, smoothish, and associated with Lasius ants. I'm not sure what they do, but Preston Hunter described a few from the US.

Keep an eye out for much larger mites with long thick legs I on Lasius - often under the mouth where they share dinner. The famous acarologist, William Morton Wheeler , has a great paper on them in Psyche - available on line (google Wheeler Antennophorus).

BugGuide has a few pictures of some Antennophorus from New Mexico - but no threat to the myrmeco's pre-eminence in photography. I'd love to see a good picture of them on an ant.

Being in such an easy to reach position, I'm surprised that the ant hadn't removed it (i guess she could have tried and failed).

Great photo.

Wow, that was fast! I might have to demote you for trying to steal Wheeler for your team, though.

Do you have an opinion about this mite?

The lateral view isn't good for characters, but it is a member of the order Mesostigmata; probably a member of the Laelapidae; and possibly a species of Myrmozercon. I would need to see the venter to be certain (even a dorsal view would help).

Unfortunately, mites in various lineages tend to colonize the same habitat over and over - and this is certainly true of the myrmecophiles. I have records for 9 genera of Laelapidae from ants. Myrmozercon, though, seems to have radiated with several ant genera, especially Camponotus.

I'm in the process of reviewing the North American Laelapidae associated with ants and describing a new species of Myrmozercon from Camponotus planatus. Jim Wetterer has sent me a heap of Myrmozercon from Campanotus species in the Carribbean and next up I will try to revise the genus for North America. If you get any mites from other Campanotus, I would be happy to look at them.

My guess is that these mites intoxicate the ants with a chemical so they are ignored or even taken care of. Of course, just because some foolish ant gives a mite a ride doesn't mean it isn't a parasite, but it may do something useful in the nest.

Most uropodoid mites disperse as deutonymphs attached to insects via an anal pedicel - a drop of glue that hardens into a little stalk - and then they let go their legs and look like little lollipops.

The mite in Alex's picture (which shows the venter), however, looks like an adult female that is holding on by legs I and/or the chelicerae. The other legs are pulled into recesses in the body and overall these mites look a bit like tortoises.

The only mites that have been demonstrated to be true parasites (as opposed to kleptoparasites) of ants are members of the same superfamily as Oplitis (Uropodoidea). But I would bet that Oplitis do something useful in the nest or at least inoffensive. A related genus, Trachyuropoda, have notches in the dorsal shield that must be for ant mandibles to pick them up and carry them (this protective behaviour ant is known for other kinds of ant mites). Could it be that ants would be so foolish as to protect their parasites?

I've been an undercover fan for a while of your website, Alex, but finally can't resist leaving a comment on this superb photo.

I'm studying mites associated with Ants and have found many Oplitis specimens on Lasius alienus in Ohio. I've found them in about 25% of all nests I've checked. They always attach at the tibial spur as adults, and I've identified them as Oplitis alienorum using Hunter & Farrier's key from 1975 that Macromite mentioned. Donisthorpe, 1927 mentioned that it is believed that the Oplitis mites attach there and eat the debris the ants rub off themselves with their tibial combs. I'm not sure if anyone has really observed this, and it seems like it might be difficult for the mite to do such a thing, but its one idea.

So far I've found 11 species of Oplitis on ants in Ohio including ants in the genera Lasius, Camponotus, Tetramorium and Formica. They seem to be very species specific.

I haven't found any Myrmozercon yet, Macromite, but have found numerous Laelapids (mostly Cosmolaelaps & Gaeolaelaps).

I only found a couple colonies of Lasius (umbratus and claviger) with Antennophorus which is an incredible mite. I took a few pictures using the microscope of them on the ants in alcohol, but they're of course nothing compared to Alex's beautiful art. Macromite if you'd like to see them I can email them to you.

Keep up the excellent blogging. I may come out of the woodwork another time!


By Kaitlin U (not verified) on 29 Mar 2010 #permalink

Go Kaitlin! I've got slides of two adult females off an Augochlora bee from Florida that look like an Oplitis. One still has a branched bee hair clutched in its chelicerae. You are welcome to them if interested.

Like to see the pickies. Haven't seen an Antennophorus on the hoof yet. I should victimize you as a beta tester of my laelapid key.

Lots of hard to believe stories about what mites are up to in ant nests.

Of course we don't have parasites like these! (At least, not on the outside, we don't...)

Ants are foolish enough to protect other inquiline parasites, like Lycaenid larvae...

Wow, that's way more information than I could possibly have hoped for. Thanks, Kaitlin! I'll definitely keep an eye out for more mites.

If you email me, I can send you the high-res version of this image.

Thanks Dave! I'll dig through my vials to see if I've got any mites from that photo session. I may well- I certainly saw several of them.