Solenopsis daguerrei

A social parasite of numerous other Solenopsis species.

Identification
Pitts et. al. (2018) - A member of the Solenopsis saevissima species-group. The males and gynes of this species are distinct from the other members of the group by their coloration, and the reduction in size, sculpturing, and wing venation associated with their socially parasitic existence. The genitalia of the male are also distinct from the other species by lacking setae on the digitus, having a reduced number of ventral setae on the volsella, and having a reduced number of ventral teeth on the aedeagus.

Distribution
Pitts et. al. (2018) - The known range of S. daguerrei extends from Buenos Aires Province, Argentina northward, including Uruguay, to Campo Grande, Brazil and eastward to Sao Paulo, Brazil (Briano et al. 1997). Solenopsis daguerrei seems to be generally sparse over most of its range. They appear to be concentrated in colonies only in certain areas (Briano et al. 1997).

Distribution based on Regional Taxon Lists
Neotropical Region: Argentina, Brazil, Paraguay, Uruguay.

Biology
Pitts et. al. (2018) - Solenopsis daguerrei has been reported to either kill the host gyne in laboratory studies (Bruch 1930) or to be an inquiline, allowing the host gyne to live (Silveira-Guido et al. 1965). Regardless of the outcome for the host gyne, the parasite lowers the egg production of the host colony and some speculation has been made regarding its use as a biological control agent (Jouvenaz 1990; Wojcik 1990). Regarding hosts, it is reported to parasitize, , and  (Santschi 1930; Briano et al. 1997; Calcaterra et al. 2000). We found S. daguerrei only in S. invicta colonies during our extensive sampling in Brazil and Argentina.

Nomenclature

 *  daguerrei. Labauchena daguerrei Santschi, 1930d: 81, fig. 12 (q.m.) ARGENTINA. Combination in Solenopsis: Ettershank, 1966: 140. Senior synonym of acuminata: Borgmeier, 1959a: 318.
 * acuminata. Labauchena acuminata Borgmeier, 1949: 208, figs. 10-14 (w.) ARGENTINA. Junior synonym of daguerrei: Borgmeier, 1959a: 318.

Pitts et. al. (2018):

Queen
Head: broader than long, quadrate, wider anterior to eyes, sides of head weakly convex from eyes to occipital angles, nearly straight anterior to eyes. Occipital angles well defined, lobate in lateral view. Vertex flattened posteriorly with narrow, transverse impression just anterior to occipital carina. Occipital furrow lacking. Frontal furrow lacking. Ocelli small, median ocellus ventral to posterior margin of eyes. Clypeus not projecting, lacking carinae or carinal teeth, anterior margin straight. Mandible gently curving, masticatory border with one large tooth and usually rudiments of two more teeth, with dorsal lobe dorsal to teeth rudiments. Eye convex, ovate, midpoint of head reaches posterior 0.33 of eye. Antennal scape in repose surpasses lateral ocellus. Antenna 11-segmented. Pedicel 2X length of second flagellomere. First and second flagellomere length each >1.5X their width.

Mesosoma. Elliptical, narrower than head. In lateral view, mesonotum convex anterior portion that greatly overhangs pronotum, lobate, posterior half straight. Pronotum wider than mesonotum. Scutellum as high as mesonotum, flattened with short, perpendicular posterior face. Angle of propodeum well-defined, obtuse, differentiation between basal and declivous faces indistinct. Mesosternum small, slightly rounded beneath. Parapsidal lines absent. Posterior and ventral margin of metapleuron fused to pronotum. Propodeal spiracle much reduced in size. Metasternal bidentate median process present. Wing venation reduced, medial cell lacking or barely discernable as such.

Metasoma. Petiolar node thick, dorsum somewhat flattened at obtuse angle, appearing to have anterior median boss on dorsum. Petiole ventrally with median carina on anterior 0.50. Postpetiole lacking ventral transverse carina, only slightly convex.

Coloration, Sculpturing, and Pilosity. Sculpture lacking, body polished, except posterior 0.25 of petiole finely striate. Setae long (0.10–0.28 mm), golden, semi-erect, somewhat longer on mesosoma than elsewhere. Color yellow with apex of mandibles and apices of metasoma segments 3–6 brown. Internal margins of ocelli yellow.

Male
Pitts et. al. (2018) - Head. Trapezoidal. Eye very large, strongly convex, ovate, occupying more than 0.5X side of head, anterior border reaching insertion of mandible. Ocelli large, prominent. Anterior edge of clypeus straight. In lateral view, clypeus shows small, blunt, beaklike central lobe. Mandible linear, with single apical tooth, lobe present dorsal to tooth. Antennal scape; 1.7X as long as broad, cylindrical. Pedicel subglobose, broader than scape or following flagellomere.

Mesosoma. Robust, elliptical. In lateral view, mesonotum swollen anteriorly, overhanging pronotum. Scutellum convex, slightly higher than mesonotum. Propodeum rounded, basal face strongly convex transversely, only slightly convex longitudinally, declivous face flat and perpendicular. Posterior and ventral margins of metapleuron fused to propodeum. Wing venation reduced, many veins being nebulous.

Metasoma. Anterior face of petiole gently sloping, posterior face abruptly curved. In lateral view, postpetiole elongate, slightly shorter than petiole. Dorsum of both with slight median longitudinal impression. Petiole dorsolaterally rounded, not bilobate. Postpetiole wider than petiole, ventral surface flat. Genitalia reduced in form, digitus lacking setae, aedeagus with few ventral teeth.

Coloration, Sculpturing, and Pilosity. All sculpture lacking except for basal 0.25 of petiole and postpetiole finely striate. Body smooth and polished. Setae golden, suberect, length 0.10–0.16 mm, mesonotum and petiolar nodes sparsely pubescent. Mesonotal pubescence sparse. Color yellow except vertex of head and gaster brown. Wings and veins hyaline.

Type Material
Pitts et. al. (2018) - Holotype (?) gyne, males. Argentina. Buenos Aires Province. Rosas. F. C. Sud. .

References based on Global Ant Biodiversity Informatics

 * Brandao, C.R.F. 1991. Adendos ao catalogo abreviado das formigas da regiao neotropical (Hymenoptera: Formicidae). Rev. Bras. Entomol. 35: 319-412.
 * Fernández, F. and S. Sendoya. 2004. Lista de las hormigas neotropicales. Biota Colombiana Volume 5, Number 1.
 * Kusnezov N. 1956. Claves para la identificación de las hormigas de la fauna argentina. Idia 104-105: 1-56.
 * Kusnezov N. 1978. Hormigas argentinas: clave para su identificación. Miscelánea. Instituto Miguel Lillo 61:1-147 + 28 pl.
 * Pesquero M. A., and A. M. Penteado-Dias. 2004. New records of Orasema xanthopus (Hymenoptera: Eucharitidae) and Solenopsis daguerrei (Hymenoptera: Formicidae) from Brazil. Braz. J. Biol., 64(3B): 737.
 * Pitts J. P., G. P. Camacho, D. Gotzek, J. V. Mchugh, and K. G. Ross. 2018. Revision of the fire ants of the Solenopsis saevissima species-group (Hymenoptera: Formicidae). Proceedings of the Entomological Society of Washington 120(2): 308-411.
 * Wild, A. L. "A catalogue of the ants of Paraguay (Hymenoptera: Formicidae)." Zootaxa 1622 (2007): 1-55.
 * Zolessi L. C. de; Y. P. de Abenante, and M. E. Philippi. 1989. Catálogo sistemático de las especies de Formícidos del Uruguay (Hymenoptera: Formicidae). Montevideo: ORCYT Unesco, 40 + ix pp.