Social Parasitism

Social parasitism is the coexistence of two or more ant species in one nest or colony. It involves a parasitic species which is dependent on one or several host species. The relationship can be obligatory or facultative, permanent or temporary. These relationships can take many forms and have been classified in various ways.

Holldobler & Wilson (1990), following a suggestion of Wasmann (1891), distinguished between "compound nests" and "mixed colonies".
 * Compound nests (xenobiosis) involve two species of ants living together in the same nest but keeping their broods separate. It includes casual or regular nesting in close vicinity (plesiobiosis), stealing food from other species (cleptobiosis), stealing brood (lestobiosis) and sharing nests and trails (parabiosis).
 * Mixed colonies comprise temporary parasites, slave-makers (dulosis) and inquilines, where the host workers care for the parasite brood, at least temporarily.

As an alternative, Buschinger (2009), in his review of social parasitism, proposed the following classification:
 * Xenobiosis (guest ants, sometimes called cleptobiosis or kleptobiosis) - The biology of Formicoxenus nitidulus provides natural history information about one representative guest ant.
 * Temporary parasitism (occurring together only during colony foundation) - The biology of Lasius umbratus provides natural history information about one representative temporarily parasitic ant.
 * Permanent parasitism with slavery (dulosis) - The biology of Temnothorax muellerianus provides a representative account of dulosis.
 * Permanent parasitism without slavery (inquilinism) - The biology of Tetramorium inquilinum (as Teleutomyrmex schneideri) provides natural history information about one representative inquiline ant.

Chemical Deception Among Social Parasites
Guillem et al. (2014) examined cuticular hydrocarbon (CHC) profiles among the parasites Camponotus universitatis, Harpagoxenus sublaevis‎‎ and Strongylognathus testaceus and their hosts. They found that the parasitic species had CHC profiles that were indistinguishable from that of their hosts, even when the parasite is using more than one host species. The level of chemical mimicry even extended to the more subtle between-colony differences in profiles. In all cases the profiles of un-parasitized colonies were similar to those that were parasitized indicating that it is the parasites that have adjusted their profile to match that of their host and not vice versa. This explains why these social parasites are fully integrated members of each colony and are treated as nest-mates.

They also noted that in some species, for example Harpagoxenus sublaevis (Winter and Buschinger, 1986), raiding workers are frequently killed or driven off when trying to raid or invade new host colonies, since they are carrying their own host colony odour, which is likely to be different from that of the one they are raiding. This is why parasites continue to use a wide range of other chemical and morphological adaptations associated with their parasitic lifestyle. These include a thickened cuticle and production of appeasement or propaganda compounds (e.g. Allies et al., 1986; Lloyd et al., 1986; Ollett et al., 1987; D'Ettorre et al., 2000). These tactics allow the parasite time to make the necessary adjustments to its profile. Acquiring a host profile may be possible in just a few hours (R. Kather, pers. comm., cited in Guillem et al. (2014)).

Parasitic Ant Species
This information has been modified from Buschinger (2009). Please cite the original publication as the source for these data.

dDul = degenerate dulosis; Dul = dulosis, slave-maker; In = inquilinism; Tp = temporary parasitism; Xen = xenobiosis, guest ant.