Slave-making ant  (Polyergus lucidus)

Polyergus lucidus is classified as Vulnerable (VU) on the IUCN Red List (1).

Polyergus lucidus is a rare, parasitic ant with an extremely curious life history; all Polyergus ants are ‘slave-making ants’ which enslave ants of other species to provide workers for their own colonies (3) (4). Polyergus lucidus workers (wingless, sterile females) are distinguished from other Amazon ants (Polyergus species) by the elongate mandibles and shiny yellowish-red body (5). The gleaming colour of the body gives rise to the species name ‘lucidus’, which means ‘bright’ in Latin. Polyergus lucidus queens (winged, reproductive females) are larger than the workers, while the males tend to be smaller (3).

Polyergus lucidus occurs in the United States, from North Dakota south to New Mexico (5).

An inhabitant of prairies and longleaf pine forests (4) (6), Polyergus lucidus has been found in both well-drained areas and poorly drained, acidic, sandy soil (7). It inhabits the nests of Formica ant species, which are generally found under stones (5) (7). 

All Amazon ants (Polyergus species) are social parasites; they raid nests of ants from the closely related Formica genus and steal the brood for rearing as slaves in their own colony (3). The colony is totally dependent on its slaves to carry out all the necessary tasks in the nest, such as brood rearing, nest maintenance (4), and foraging; the Formica slaves regurgitate food for Polyergus lucidus to feed on (3).

As the Formica slaves die-off, more are captured to replace them, with raids of Formica nests taking place every six to eight weeks (3). During such raids, as well as bringing larvae and pupae back to the nest, Polyergus lucidus workers also eat a large proportion of the Formica eggs (3).

Polyergus lucidus queens (winged females) mate during a flight which occurs around midday in high temperatures (8). The males do not survive long after reproduction, while the queens lose their wings and go on to found a new colony (9). 

Slave-making ants such as Polyergus lucidus are entirely reliant on their host species and typically have smaller populations than other ant species, making them more vulnerable to disturbances (4). The longleaf pine which makes up the habitat of Polyergus lucidus and its slaves in the south-eastern United States is now considered a threatened ecosystem with a distribution of only three percent of what it once was (4). There have also been cases where entire colonies of Polyergus lucidus have become inactive and died out, thought to be due to an unknown disease (7). 

There are currently no known specific conservation efforts in place for this rare ant; however, it does occur in the Apalachicola National Forest in Florida (and possibly also in other protected areas throughout its range), which may offer Polyergus lucidus some level of protection by conserving the habitat in which it occurs (4).

To learn more about the conservation of ants and other insects see:

• The Xerces Society:
  http://www.xerces.org/
• Buglife:
  http://www.buglife.org.uk/