Formica gerardi

This ant has been associated with the butterflies  Laeosopis roboris and  Favonius quercus (Obregon et al. 2015).

Identification
Gómez et al. (2018) - The following combination of morphological characters has been used to isolate Formica gerardi from other close species (Formica lemani, Formica fusca, Formica decipiens and European Formica of the rufibarbis group). Ecological requirements and habitat types used by those species are also indicative – Formica gerardi is the most xerothermic species within European Formica– and are currently in use during field work.

- Colour light to dark brown, sometimes with reddish brown areas at the sides of pronotum and pro-mesonotum lateral juncture.

- Body surface appearing, at low magnification (<20X), as absolutely matte.

- Internal face of tibiae III with diluted pubescence. Pubescent setae could be described as flat, wide and very appressed over tibial surface. Instead, in Formica lemani, Formica fusca, Formica decipiens, and European Formica rufibarbis group, the internal face of tibia III pubescence density is much higher (see figure 2). Formica picea, strangely enough, approaches Formica gerardi condition in tibial pubescence density but has otherwise clear differences in surface shininess, pilosity and colouration.

- Pronotum and mesonotum with short erect setae

- Propodeum lower than in European Formica rufibarbis group species.

The long scapes and dull frontal triangle places it in the Serviformica subgenus, and its dull cuticle differentiates it from the rest of Iberian Serviformica queens in which scutellum is smooth and shining.

As in the worker and queen castes, the dull, mattete appearance differentiates the Formica gerardi male from all the other Serviformica males present in the Iberian Peninsula, which have shiny mesopleurae.

Collingwood and Yarrow (1969) - This species is described by Bondroit (1917) as brown-black, very matt with short grey pubescence; anterior of head, sutures, antennae and legs lighter and with sparse hairs on head, gaster and pronotum. It is in effect like a dark Formica rufibarbis. The dorsal thoracic hairs in these examples are less concentrated on the pronotum than in F. rufibarbis, more scattered over the whole thorax, finer and fewer in number. The main structural difference between the two species is in the shape of the epinotum which is relatively lower and less massive in F. gerardi, having the ratio of length of dorsal surface to height as 8: 10 instead of about 7: 10.

Distribution based on Regional Taxon Lists
Palaearctic Region: Andorra, France, Gibraltar, Iberian Peninsula, Portugal, Spain.

Biology
Gómez et al. (2018) provided biological details about F. gerardi through a discussion of how this ant's biology could, in part, differentiate it from a similar species: Behavioral and ecological differences: Iberoformica subrufa and Formica gerardi share the fact of being thermophilic ants, living in the Mediterranean forests clearings. Although both species can share the same habitat occasionally, Iberoformica subrufa may be present in the same localities as other highly thermophilic species like Camponotus foreli or Cataglyphis velox, while Formica gerardi is more dependent on shaded areas. Being less thermophilic, Formica gerardi extends its distribution to the Northern Iberian meseta, where Iberoformica subrufa is present only in isolated areas, and the opposite in the South Iberian Peninsula, where Iberoformica subrufa is common and Formica gerardi needs forest-shaded areas to live. One main behavioral difference between both species is that Iberoformica subrufa has not known dulotic relation with Polyergus species, while various ants belonging in the fusca group are commonly enslaved by them. In its revision of the genus Polyergus, Trager writes about Polyergus rufescens: “I have series from the Pyrenees with Formica gerardi, where this is the most abundant potential host” (Trager, 2013: 511). One of us (F. García) has also found these two species in dulotic relation in Ayora (Valencia province, 39°06’59”N 1°12’37”W 850m, 18/02/2017), in a Pinus halepensis pinewood where Formica gerardi was one of the most frequent species. Iberoformica subrufa was also present and frequent but was never found in dulotic relation with Polyergus rufescens.

Nomenclature

 *  gerardi. Formica gerardi Bondroit, 1917b: 186 (w.) FRANCE.
 * Lorite, Chica & Palomeque, 1998: 26 (k.).
 * Combination in F. (Iberoformica): Czechowski, Radchenko, et al. 2012: 39.
 * Combination in F. (Serviformica): Gomez, Lorite, et al. 2018: 464.
 * As unavailable (infrasubspecific) name: Emery, 1925b: 247.
 * Junior synonym of subrufa: Bernard, 1967: 301.
 * Status as species: Bondroit, 1918: 53; Stärcke, 1926: 148 (in key); Schmitz, 1950: 14; Collingwood & Yarrow, 1969: 89; Collingwood, 1978: 94 (in key); Bolton, 1995b: 195; Casevitz-Weulersse & Galkowsky, 2009: 482; Borowiec, L. 2014: 75.

Queen
Gómez et al. (2018) - HL=1.7 [1.36-1.91], HW=1.71 [1.53-1.89] , SL=1.6 [1.3- 1.81] , EL=0.63 [0.55-0.74] , WL=3.13 [2.86-3.57] , PW=1.67 [1.3-1.9] , PLD=2.61 [2.33-2.97] , OI (EL/HW)=37 [33-48] , CI (HW/HL)=100 [95-112] , SI (SL/HW)=93 [84-100] , MI (PW/ HW)=98 [78-133] , MDI (PW/PLD)=64 [49-77] (n=9)

Head subquadrate, smaller basally. Mandibles striated, strong and with 6-7 acute teeth in the masticatory margin. Clypeus convex, with a medial carina. Frontal ridges short. Scapes long, surpassing the occipital border, funiculus with four first segments elongated, the remainder subquadrate. Pronotum dorsally visible and relatively low in lateral view in the smaller specimens. Scutum rounded in profile view, scutellum flat in profile view and subquadrate in dorsal view. Propodeum a straight line to the insertion with petiole. Scutoscutellum suture demarcated but not deep. Petiole squamiform, high, narrowly ovate in profile view. Subrectangular in frontal view, convex with a medial notch. Gaster as wide as mesosoma in dorsal view. Whole body covered with a short, whitish pubescence. Long, erect to semierect white setae present following the frontal ridges to occipital margin of the head (5 to 10), abundant on clypeus (10-15), numerous (>10) and sudecumbent on pronotal dorsum, semierect on dorsum of mesosoma (>20) and abdomen. Rest of the head, propodeum and petiole with appressed pubescence only. Body and head entirely shagreened and dull due to heavy sculpturation except frontal suture, central-anterior line of scutellum and two symmetrical lateral lines in its posterior half. Colour entirely dark brown to black, with the appendages lighter. A reddish band present in the borders of the pronotum and mesopleurae. Head below eyes and mandibles with a more or less developed reddish tinge.

Male
FGPCHL=1.30 [1.27-1.36], HW=1.53 [1.48- 1.58] , SL=1.27 [1.23-1.33] , EL=0.73 [0.71-0.76] , WL=2.73 [1.18-3.28] , PW=1.92 [1.66-2.14] , PLD=2.70 [2.47-2.89] , OI (EL/HW)=47 [46-49] , CI (HW/HL)=117 [113-123] , SI (SL/HW)=83 [81-84] , MI (PW/HW)=146 [130-162] , MDI (PW/PLD)=71 [67-80] (n=5).

Head triangular, widest at apex, wider than long (CI~117), vertex convex, lateral a straight line; clypeus convex, medial carina weak but present; mandibles sublinear, slightly rugulose; apical tooth present, followed by a edentate border with 0-1 denticles; eyes large (OI~47); three conspicuous ocelli present and elevated over the rest of the head, the center one oriented forward, the other two laterally; frontal ridges absent, vestigial laterally with exposed antennal sockets. Scapes long (SI~83) surpassing the occipital border when laid back, the length between occipital border and apex clearly longer than distal to occipital border; funiculus filiform with all funicular segments longer than wide, similar in size. Mesosoma clearly wider than head (MI~146). Pronotum almost not visible in dorsal view, slightly depressed in the medial line. Scutum rounded, notauli absent, parapsidal lines clearly demarcated. Scutelllum rounded dorsally and laterally, elevated over the scutum. Posteropropodeum clearly longer than dorsopropodeum, rounded in lateral view. Petiole low; in profile view rounded, subovoid and almost symmetrical, with an acute apex; in frontal view trapezoidal, with straight dorsal line and vertical lateral sides connected by two 45 degree almost straight lines. Gaster long and cylindrical. Genitalia typical of genus Formica (Figures 4, 5). Sagitta with apex recurved and rounded, the border of its ventral half dentated. Digitus recurved. Dark brown to black, with legs and funiculus light brown to brown. Head surface mattete except for the frontal line from clypeus to central ocellus. Rest of body sculptured with the same pattern than worker, mattete (Figure 3). 1-2 pairs of semierect to erect setae on clypeus medially on clypeus, one on vertex and one setae more below each lateral ocelli. Mesosoma dorsally with scattered yellow, short semierect to erect setae, slightly longer than pubescence, absent on propodeum. Petiole with scattered erect short setae, as long as the pubescence. Whole body covered with yellowish, dense long pubescence, its length clearly longer than distance between pubescence lines, overlapping.