Pheidole bilimeki

P. bilimeki is an abundant and common species throughout its range. It nests almost anywhere including in rotten wood and under stones and inhabits mostly open and highly disturbed areas.

Identification
One of a number of species once suggested (Wilson 2003) to be the single highly variable species P. bilimeki. This species, now more narrowly defined, has minor workers that have shorter scapes than the closely related Pheidole anastasii. The head of the minor of bilimeki is also less rounded behind and both majors and minors are brown. The current understanding of this species now excludes the Hispaniola and Jamaica bilimeki like form Pheidole jamaicensis.

P. anastasii overlaps in its range with P. bilimeki. These two species maintain clear ecology differences, primarily in habitat preferences, that are diagnostic: P. anastasii nests in plant cavities in the shaded understory of mature or second growth wet forest. In contrast, P. bilimeki nests almost anywhere, including in rotten wood and under stones, but occurs mostly in open and highly disturbed areas.

The following can be helpful in separating bilimeki-like Phediole (Longino and Cox 2009):

1
 * Scape relatively short (SI 95–108, lower cloud of points in Fig. 1); posterior margin of vertex somewhat flattened; color usually brown, yellow in northern parts of range . . . . . Pheidole bilimeki
 * Scape relatively long (SI typically 103–125, upper cloud of points in Fig. 1); posterior margin of vertex more rounded (Fig. 2 B, C, E); color brown or yellow . . . . . 2

2
 * Color clear yellow orange (gray brown in one population on Caribbean coast of Panama); typically nesting in live plant cavities in wet forest understory . . . . . Pheidole anastasii
 * Color red brown to nearly black; typically nesting in open, disturbed habitats . . . . . 3

3
 * Scapes relatively shorter (SI 108–114, see Fig. 1) (major worker with face uniformly red brown) . . . . . Pheidole jamaicensis
 * Scapes relatively longer (SI 114–125, see Fig. 1) (major worker with face bicolored, dark red brown anteriorly, yellow posteriorly) . . . . . Pheidole punctatissima

Distribution
This species is native to the Neotropical region, from the north of South America to the south of North America, and is present throughout the Caribbean (Guénard, Weiser, Gomez, Narula, & Economo, 2017). It has been introduced into the Nearctic and Palaearctic regions (Antweb, 2019; Guénard et al., 2017; Sarnat et al., 2015). In the Canaries, it has only appeared in three localities on Tenerife and ten on La Gomera (Hernandez-Teixidor et al., 2020).

Distribution based on Regional Taxon Lists
Neotropical Region: Bahamas, Belize, Colombia, Costa Rica, Cuba, Greater Antilles, Guatemala, Honduras, Mexico, Nicaragua, Panama, Venezuela.

Habitat
Occurs in all tropical climate zones where ants occur: lowland dry forest, lowland wet forest, and montane habitats to about 1500m elevation.

Biology
Longino and Cox (2009) - This is a heterogenous assemblage that may itself prove to be multiple species when more material is available. The main feature differentiating P. bilimeki from Pheidole anastasii, Pheidole jamaicensis and Pheidole punctatissima is the shorter scapes. Typically specimens are uniformly red brown, but some collections from the northern part of the range, including the type of P. bilimeki, are yellow orange, like P. anastasii. The sculpture on the first gastral tergite is highly variable. There is always some degree of shagreened, opaque sculpture anteriorly, around the postpetiolar insertion, but it varies from covering the entire tergite to covering only about the anterior third. Within nest series, shagreening is typically more extensive on minor workers than major workers; in many series where the first gastral tergite is completely shagreened in the minor worker, only the anterior third is sculptured in the major. Pheidole bilimeki is a common species in open, recently or frequently disturbed habitats. It occurs in all tropical climate zones where ants occur: lowland dry forest, lowland wet forest, and montane habitats to about 1500m elevation. In Costa Rica it is a common ant of roadsides, nesting under stones or in dead fenceposts. It is a frequent pest ant in houses. It is a common ant at baits in second growth dry forest vegetation in seasonally dry Guanacaste Province. It can also be abundant in large disturbances deep within primary forest reserves. The Peñas Blancas Valley is a large forested reserve in the Cordillera de Tilarán in northern Costa Rica. In 2001 there was a large debris torrent that created a very large area currently undergoing primary succession. The area is about 5km from the edge of the reserve and human settlement. As of early 2008 the area was dominated by P. bilimeki.

At La Selva Biological Station, in lowland rainforest on the Atlantic slope, P. bilimeki is abundant in the laboratory clearing, where it can be a pest ant in buildings. It is never found in the forest. At Sirena in Corcovado National Park in southeastern Costa Rica, P. bilimeki is common in the vegetation of the upper beach margin and extending less than 20m into the forest.

In the Canary Islands, where it has been introduced, it is occasionally found inside houses, but more frequently in greenhouses (Sarnat et al., 2015). There is little indication that this species causes a significant impact on agricultural systems or native ecosystems. As it has low tolerance for cold climates, it is not considered a highly invasive species (Sarnat et al., 2015; Hernandez-Teixidor et al., 2020).

Worker
Minor

Nomenclature

 *  bilimeki. Pheidole bilimeki Mayr, 1870b: 985 (s.q.) MEXICO. Senior synonym of annectens, antoniensis, ares, cellarum, deplanata, insulana, johnsoni, venezuelana: Wilson, 2003: 378; of rectiluma: Longino, 2009: 16.
 * deplanata. Pheidole floridana var. deplanata Pergande, 1896: 883 (s.w.) MEXICO. Junior synonym of bilimeki: Wilson, 2003: 378.
 * antoniensis. Pheidole floridana var. antoniensis Forel, 1901e: 364 (s.w.) COLOMBIA. Junior synonym of bilimeki: Wilson, 2003: 378.
 * annectens. Pheidole punctatissima subsp. annectens Wheeler, W.M. 1905b: 93 (s.w.q.) BAHAMAS. Junior synonym of bilimeki: Wilson, 2003: 378.
 * insulana. Pheidole punctatissima subsp. insulana Wheeler, W.M. 1905b: 93 (s.w.) BAHAMAS. Junior synonym of bilimeki: Wilson, 2003: 378.
 * venezuelana. Pheidole anastasii var. venezuelana Forel, 1905b: 159 (s.m.) VENEZUELA. Junior synonym of bilimeki: Wilson, 2003: 378.
 * johnsoni. Pheidole anastasii var. johnsoni Wheeler, W.M. 1907a: 272 (s.w.m.) HONDURAS. Junior synonym of bilimeki: Wilson, 2003: 378.
 * ares. Pheidole floridana subsp. ares Forel, 1908b: 57 (s.w.m.) COSTA RICA. Junior synonym of bilimeki: Wilson, 2003: 378.
 * cellarum. Pheidole anastasii var. cellarum Forel, 1908b: 55 (s.w.) SWITZERLAND (in greenhouse). Forel, 1915d: 34 (q.). Junior synonym of bilimeki: Wilson, 2003: 378.
 * rectiluma. Pheidole rectiluma Wilson, 2003: 493, figs. (s.w.) MEXICO. Junior synonym of bilimeki: Longino, 2009: 16.

Description
Longino and Cox (2009) - Pheidole anastasii, Pheidole bilimeki, Pheidole jamaicensis and Pheidole punctatissima share the following traits:

Minor worker: head width (not including eyes) 0.38 to 0.55mm; scape length 0.40 to 0.60mm; scape index (100 * scape length / head width) 95 to 125; face and mesosoma uniformly foveolate; promesonotal groove very weakly or not at all impressed; with short upturned propodeal spines; postpetiole broad and low, somewhat flattened, lower than petiolar node; first gastral tergite with anterior third to entire surface shagreened; pilosity on mesosomal dorsum sparse and stiff; pilosity on hind tibia fully appressed and short.

Major worker: head width 0.74 to 1.09mm; scape length 0.44 to 0.63mm; scape index 50 to 68; face largely foveolate rugose, with variable extent smooth and shiny posteriorly; hypostomal margin with two closely-spaced medial teeth; first gastral tergite with anterior third to entire surface shagreened.



'''Figure. Upper: major. Lower: minor. COSTA RICA: Costa del Tablazo, 1500 m (syntypes of synonymous P. ares Forel, compared with bilimeki lectotype). Scale bars = 1 mm.'''

Type Material
Mexico. - as reported in Wilson (2003)

Etymology
Patronym.

References based on Global Ant Biodiversity Informatics

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