Formicoxenus nitidulus

A xenobiont that is unique within Formicoxenus in being able to survive in the nests of at least 11 different ant host species.

Identification
Reddish yellow to brown: whole surface of body smooth and shining with scattered acute pale hairs. Antennal club 3 segmented as long as rest of funiculus: propodeal spines short, set horizontally. Length: 2.8-3.4 mm (Collingwood 1979).

Distribution
Spain to Eastern Siberia. North Italy to latitude 70º N (Collingwood 1979).

Distribution based on Regional Taxon Lists
Palaearctic Region: Austria, Belarus, Belgium, Bulgaria, Croatia, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iberian Peninsula, Italy, Latvia, Lithuania, Luxembourg, Netherlands, Norway, Poland, Republic of Moldova, Romania, Russian Federation, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey, Ukraine, United Kingdom of Great Britain and Northern Ireland.

Biology
Collingwood (1979) - This ant occurs only in the nests of Formica rufa and allied mound building species. It is ignored by its host among which the xenobiont species moves freely. Individual nests contain only a few individuals, up to about 100, but often several nests are present within one mound of the host. Nests are located in fragments of wood, hollow twigs, bases of old bracken stems and in the earth floor of the Formica mound. Individuals normally remain concealed within the nests but may wander on the mound surface on warm dull days. It is not known to feed on the Formica brood but in captivity will destroy Leptothorax larvae. Males and winged females may be found during July and August. Mating occurring on the surface of the Formica mound.

Ergatoid queens (i.e. wingless at emergence) are frequent. Mated egg-layers include dealate queens and ergatoid queens. Workers and sexuals are able to solicit food from wood ants, either directly, or the guest ant climbs up the legs and thorax to the head of a host ant that is engaged in food exchange with another Formica, then steals a little food from the droplet the two ants have between their mandibles.

Known Hosts
Formicoxenus nitidulus is known to occur in the nests of the following species (Wilson 1971; Holldobler & Wilson 1990; Busch 2001).

Castes
Francoeur et al. (1985) described ergatoid queens to have 1-3 ocelli and other traits resembling more or less the winged queens

Nomenclature

 *  nitidulus. Myrmica nitidula Nylander, 1846b: 1058 (w.) FINLAND. Nylander, 1849: 34 (q.); Mayr, 1855: 419 (m.). Combination in Formicoxenus: Mayr, 1855: 418. Senior synonym of laeviuscula: Mayr, 1855: 418; of picea: Francoeur, Loiselle & Buschinger, 1985: 380. See also: Kutter, 1977c: 144; Francoeur, Loiselle & Buschinger, 1985: 380; Radchenko, 2007: 32.
 * laeviuscula. Myrmica laeviuscula Foerster, 1850a: 54 (q.) GERMANY. Junior synonym of nitidulus: Mayr, 1855: 418.
 * picea. Leptothorax nitidulus var. picea Wasmann, 1906: 120 (w.) LUXEMBOURG. Junior synonym of nitidulus: Francoeur, Loiselle & Buschinger, 1985: 380.