Aphaenogaster senilis

Observed on open, sunny locations: forest edges, lawns, fields with scattered shrubs, urban areas. Nest in soil, mostly sheltered by stones; workers are individual foragers on the ground, in herbs and bases of trees and shrubs. Fast moving after disturbance. Details about colony structure (Boulay et al. 2007): <four gynes per colony, mean colony size 1260 specimens (Boer, 2013).

The original description of this species was based on Sardinian specimens (Mayr 1853). On the island it seems confined to the southernmost provinces, where it is often abundant. However, it is a West-Mediterranean taxon, widespread from the Canary Islands to southern France and especially common in the Iberian Peninsula (Cagniant et al. 1991; Rigato & Toni, 2011). Aphaenogaster senilis is an important seed disperser.

Distribution based on Regional Taxon Lists
Palaearctic Region: Balearic Islands, Canary Islands, France, Gibraltar, Iberian Peninsula, Italy, Portugal, Spain.

Biology
Worker numbers average 1,260 &plusmn; 69 (mean &plusmn; SE, n=168, range 121-3,906) (Bouley et al. 2007). Nest density was found to be 174 nests ha-1 at a site in southern Spain. Foraging is strictly diurnal and occurs from February to November. Colonies will move their nests frequently, occupying open areas in spring and fall and shady sites during the heat of the summer. (Barraso et al. 2013)

Reproduction
Aphaenogaster senilis produces new colonies via fission. Sex ratios are highly male biased (172:1, numerically). New sexuals were much more likely to be produced in queenless colonies. Workers can have functional ovaries and are likely able to produce males from their eggs, provided they are allowed to develop. Queens are hypothesized to produce pheromones that suppress the production of new sexuals. (Bouley et al. 2007)

Chemistry
The contents of the Dufours gland and postpharyngeal gland have been examined for workers and queens. (Bouley et al. 2007)

Nomenclature

 *  senilis. Aphaenogaster senilis Mayr, 1853b: 108 (w.q.) ITALY. Emery, 1916b: 140 (m.). Junior synonym of testaceopilosa: Nylander, 1856b: 86; Smith, F. 1858b: 165 (misspelled as similis); Roger, 1859: 255; Dalla Torre, 1893: 107. Subspecies of testaceopilosa: Emery, 1878b: 53; Emery, 1916b: 131; Santschi, 1919e: 245. Revived status as species: Bondroit, 1918: 161; Santschi, 1933c: 396; Cagniant, 1964: 100; Bernard, 1967: 132. Baroni Urbani, 1971c: 44. Senior synonym of acoreensis: Yarrow, 1967: 26; of fuentei: Collingwood, 1978: 67; of occidua: Casevitz-Weulerrse & Galkowski, 2009: 486; of grata, occidua: Boer, 2013: 81. Current subspecies: nominal plus disjuncta.
 * acoreensis. Aphaenogaster senilis var. acoreensis Santschi, 1933a: 21 (q.) AZORES IS. [Also described as new by Santschi, 1933c: 397.] Junior synonym of senilis: Yarrow, 1967: 26.
 * fuentei. Aphaenogaster testaceopilosa var. fuentei Medina, 1893: 105 (w.) SPAIN. Junior synonym of senilis: Collingwood, 1978: 67.
 * grata. Aphaenogaster senilis var. grata Santschi, 1933c: 397, fig. 34 (m.) SPAIN. Junior synonym of senilis: Boer, 2013: 81.
 * occidua. Aphaenogaster senilis var. occidua Santschi, 1933c: 396, fig. 26 (w.m.) FRANCE. Junior synonym of senilis: Casevitz-Weulerrse & Galkowski, 2009: 486, Boer, 2013: 81.