Polyergus breviceps

(Slave Raiding Ant)

Polyergus breviceps is an obligate social parasite on Formica ants. Polyergus queens force their way into a host nest, kill the host queens, then have the newly enslaved Formica workers raise the Polyergus queen's brood. When these brood mature, the Polyergus workers begin slave raids on more Formica nests, stealing Formica pupae and larvae for food and as future slaves.

The Polyergus workers do very, very little to maintain the nest - their Formica slaves gather food, maintain the nest on their own. If the ants relocate the nest, the Polyergus workers don't even move themselves to the new nest - the Formica workers carry them!

These photos show Polyergus workers carrying larvae and pupae back to their nest after a successful slave raid, and here is an Apple QuickTime video of the workers returning from a slave raid.

To the left is a photo of a Polyergus worker grooming herself at the nest prior to a raid. You can see how she has sickle shaped mandibles, specialized for piercing the exoskeletons of other ants.

These photos were taken in Arizona's Chiricahua Mountains, near the Southwest Research Station.

The picture at lower left shows a Polyergus worker returning to the nest with a Formica larvae. The Polyergus worker has a lot of mites on her - the full sized photo shows six or seven. Mites seem to be quite prevalent on Polyergus, I'm not sure if this is true in general or just in the ants that we happened to see.