One of these ants is not like the other ones...

Who's that odd ant out?

While in sunny Florida last summer (ah, sunshine! I vaguely remember what that looks like), I spent an hour peering into a nest of little Dorymyrmex elegans. These slender, graceful ants are among Florida's more charming insects.

Every few minutes, though, the flow of elegant orange insects out of the nest was interrupted by a darker, more robust ant: Dorymyrmex reginicula. Who was this interloper?

Dorymyrmex reginicula is a temporary social parasite. Mature colonies behave pretty much like normal ants. Workers guard the nest, forage for food, and tend the larvae. The queen lays the eggs. Nothing unusual there.

But new colonies are a different matter. Instead of starting with a young mated queen, cloistered in a chamber and patiently rearing a crop of workers on her own, D. reginicula skips those difficult early steps. She invades an existing ant colony. If she's successful in usurping the position of the resident queen, the colony will slowly metamorphose from the host species to her own, with an intermediate period when older workers of the attacked nest coexist with the newly emerged workers of the parasite.

I've normally seen D. reginicula infiltrating nests of the common D. bureni. But this nest was of the rarer D. elegans, and the transition didn't appear smooth. The host ants were putting up belated resistance, occasionally attacking the D. reginicula workers. It's a futile fight as their own queen must already have succumbed, but it did provide great drama for a photo shoot.

A tangle at the nest entrance.

Grabbing the problem by the jaws...

...or the legs.

A Dorymyrmex reginicula worker, free of her tormentors.

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wow... that's so interesting.. and i concur with Slamduck, the photos are GREAT.

I love ant colonies... people need to stop and watch an ant colony just for one hour... there's so much drama going down!

The first D. reginiculus colonies I found were in a dense population of D. bossutus, and I thought for a while that this species might be their only temporary host. Your fabulous pictures and accompanying text clearly demonstrate otherwise.

Also notable is that a similar, though less shiny and a bit darker Florida species D. medeis (a.k.a. smithi, but I think erroneously) is parasitic on D. bureni (at least). This one also seems to start out from a queen invading the host nest alone, but then colonies grow and spread into multiple nests by raiding and taking over nearby host colonies.

Again, really nice images! (And possibly the first of either of these not-so-common species?)

I know you must tire of this (well.. may not!), but these really are superb photographs. Technically excellent, but that's not what makes them; I like them because they illustrate a behavior so well. Very nice indeed.

By Pete Yeeles (not verified) on 04 Mar 2010 #permalink

With my parasitic formica colony, the host species seem to care for the parasites like babies! They drag them around and carry them. Very odd behavior!

By robomantis (not verified) on 05 Mar 2010 #permalink

When I worked at Archbold years ago, I collected D. medeis in association with D. bureni. It was, I think, the first record of that species for the station. I more typically found D. reginiculus with D. bureni as well- but apparently it is more frequently associated with D. bossutus?

Anyway, thanks for commenting James. It's always a treat to hear from the guy who described these species.

One more thing, The darker species should correctly be called D. reginicula (meaning -- the small-queen dorymyrmex). The specific epithet is a noun in aposition, and thus remains in its original form, no matter what happens to the gender of the genus name.

Ah. I like that better anyway. I had been calling it reginicula but deferred to antweb's spelling for this post. I've gone back and changed the spellings.