Solenopsis megergates

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Solenopsis megergates
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Hymenoptera
Family: Formicidae
Subfamily: Myrmicinae
Tribe: Solenopsidini
Genus: Solenopsis
Species group: saevissima
Species: S. megergates
Binomial name
Solenopsis megergates
Trager, 1991

Solenopsis megergates casent0178141 profile 1.jpg

Solenopsis megergates casent0178141 dorsal 1.jpg

Specimen labels

The only specimen record with collection details notes the ant was found at a gas station. Nothing is known about the biology of Solenopsis megergates.

Identification

Pitts et. al. (2018) - A member of the Solenopsis saevissima species-group. Gynes and workers of S. megergates are similar in coloration. The workers of this species are the largest of any of the fire ants. The gynes, along with those of Solenopsis macdonaghi and Solenopsis saevissima, are the largest gynes in this group. The darker-colored gynes of S. megergates could be confused with Solenopsis invicta, but the CI and OI of S. megergates are normally larger than those of S. invicta. In many cases, the sculpture of the mandible and postpetiole for workers can help separate S. megergates from similar species.

The males of S. megergates are distinct from all other species by lacking sculpture on the lateral faces of the scutellum; the males of the other species have weakly to strongly striate lateral faces. Also, the males of S. megergates usually have smaller ocelli than their closest relatives (Pitts et al. 2005), S. macdonaghi and Solenopsis quinquecuspis.

The larvae of S. megergates are distinct from the S. saevissima type by having simple setae on the head capsule. The larvae are virtually identical to S. macdonaghi and S. quinquecuspis. The S. megergates larvae have bifid setae on the body that differ slightly from S. macdonaghi and S. quinquecuspis by having a slightly longer base.

Keys including this Species

Distribution

Pitts et. al. (2018) - The type series locality is Curitiba, Parana, Brazil (Trager 1991). Solenopsis megergates is currently known only from the three southern Brazilian states of Parana, Santa Catarina, and Rio Grande do Sul.

Distribution based on Regional Taxon Lists

Neotropical Region: Brazil (type locality), Paraguay.


Distribution based on AntMaps

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Distribution based on AntWeb specimens

Check data from AntWeb

Biology

Castes

Worker

Nomenclature

The following information is derived from Barry Bolton's New General Catalogue, a catalogue of the world's ants.

  • megergates. Solenopsis megergates Trager, 1991: 181, figs. 68, 69, 72, 73 (w.q.) BRAZIL.

Pitts et. al. (2018):

Description

Worker

Head broad, cordate. Head sculpture with small piligerous foveolae, approximately 0.01 mm in diameter. Median frontal streak absent or faint. Median ocellus in largest major workers present. Mandibular costulae usually present throughout, sometimes obsolescent. Mesonotum with 20–25 setae. Mesonotum weakly convex, in lateral view. Promesonotal suture in largest major workers angulate, sometimes projecting upward. Propodeum sculpture glabrous posteroventral to spiracle. In largest major workers, propodeum curves directly to flattened posterior portion. Postpetiole shape much broader than high. Postpetiole in posterior view transversely rugose on lower 0.50–0.75, weakly granulate, sculpture not extending to dorsum. Color red brown on head, mesosoma, legs and T1 maculation. Color dark brown on metasoma excluding maculation.

Queen

Head. Slightly broader than long, quadrate, sides of head convex from eyes to occipital angles, straight to nearly straight ventral to eyes. Eye sometimes with 3–4 setae protruding from between ommatidia, length most setae <3X length of ommatidium, sometimes setae longer, ~4X length of ommatidium. Ocelli large, prominent. Median ocellus circular, lateral ocelli slightly ovate. Clypeus projecting, carinal teeth stout and sharp, carinae well defined, less so dorsally, slightly divergent ventrally. Paracarinal teeth small, sometimes poorly defined. Median clypeal tooth well developed, infrequently indistinct. Approximately 0.50 of eye dorsal to midpoint of head.

Mesosoma. Parapsidal lines present on posterior 0.50 of disk. Mesonotum with indistinct, posteromedian furrow. Wing venation as in Fig.

Metasoma. Lateral faces of postpetiole straight to weakly concave. Petiolar and postpetiolar spiracles tuberculate in some cases.

Coloration, Sculpturing, and Pilosity. Piligerous foveolae moderate, width 0.005–0.03 mm in diameter, larger on head than on thorax and abdomen. Pubescence simple, golden and erect, longer and denser on head than elsewhere, longest on anterior edge of clypeus. Mesosoma with longest pubescence (length >0.30 mm) 2X longer than shortest pubescence. Sometimes fine striae present between ocelli. Mandible with 5–7 coarse, distinct costulae present, sometimes obsolescent medially. Propodeum with fine striae posteriorly, anterior 0.25 polished. Petiolar nodes with lower 0.50 of posterior surface finely striate to granulate, dorsum polished. Postpetiole with 12–16 striations, dorsum finely granulate to polished. Remaining integument smooth and polished. Color varies from red brown to brown orange. Ocellar triangle sometimes darkly pigmented. Legs usually red brown, sometimes becoming lighter than body (yellow brown). Mesonotal maculations present anteromedially and parapsidal lines, usually black to dark brown, sometimes only slightly discernable from surrounding integument. Integument along internal margins of ocelli usually brown. Median frontal streak absent, sometimes area is slightly darker than surrounding integument.

L ~7.4–8.9, HW 1.35–1.68, VW 0.90–1.02, HL 1.22–1.42, EL 0.40–0.48, OD 0.14–0.20, OOD 0.20–0.28, LOW 0.10–0.12, MOW 0.10–0.12, CD 0.16–0.26, MFC 0.16–0.28, EW 0.30–0.42, SL 0.95–1.15, PDL 0.21–0.25, LF1 0.10–0.14, LF2 0.08–0.11, LF3 0.07–0.11, WF1 0.05–0.08, FL 1.15–1.32, FW 0.25–0.30, MW 1.46–1.54, DLM 2.51–2.82, PRH 0.90–1.25, PL 0.71–0.79, PND 0.55–0.68, PH 0.65–0.75, PPL 0.30–0.41, DPW 0.56–0.68, PPW 0.74–0.79, PHB 0.38–0.45, N=6.

Male

Head. Eye normally with 3–4 setae protruding from between ommatidia, setal length ≤ 3X width of ommatidium. Ocelli moderate to small, elliptical.

Mesosoma. Propodeum rounded, declivous face perpendicular, flat except with distinct to indistinct median longitudinal depression, basal face strongly convex transversely and longitudinally. Metapleuron not broad, ~0.33 as wide as high. Wing venation as in Fig.

Metasoma. In anterior view, dorsum of node with deep median impression, bilobate. Petiolar and postpetiolar spiracles distinctly tuberculate to not tuberculate. Genitalia as in Figs.

Coloration, Sculpturing, and Pilosity. Pubescence short, thin, yellow, erect to suberect and of uniform length over body (0.25–0.30 mm), longest on gena and vertex. Mesonotal pubescence dense. Propodeum with base striato-granulate. Area between eye and insertion of antenna, posterior portion of metapleuron, and base of petiolar node granulate. Sometimes, base of petiolar node rugose to striato-granulate. Area between ocelli and gena striato-granulate. Vertex granulate. Areas anterolateral to median ocellus usually glabrous. Lower 0.25 of postpetiole finely striatogranulate to granulate, remaining surface granulate. Lateral faces of scutellum glabrous. Remaining integument smooth and polished. Color red brown to brown, antennae and legs brown yellow. Mandibles yellow to yellow brown.

L ~5.0–6.7, HW 0.97–1.10, VW 0.30–0.38, HL 0.66–0.80, EL 0.40–0.49, OD 0.06–0.09, OOD 0.12–0.18, LOW 0.09–0.12, MOW 0.10–0.15, CD 0.15–0.18, MFC 0.13–0.16, EW 0.30–0.38, SL 0.16–0.18, SW 0.09–0.10, PDL 0.05–0.06, PEW 0.10–0.15, LF1 0.14–0.21, LF2 0.10–0.15, LF3 0.13–0.16, WF1 0.06–0.09, FL 1.04–1.11, FW 0.16–0.21, MW 1.40–1.54, DLM 2.35–2.44, PRH 0.81–1.05, PL 0.61–0.66, PND 0.56–0.61, PH 0.46–0.54, PPL 0.22–0.31, DPW 0.56–0.63, PPW 0.65–0.69, PHB 0.21–0.28, N=8.

Larva

Fourth instar worker larva.—Head. Large, subpyriform in anterior view (height 0.46 mm, width 0.50 mm). Cranium slightly broader than long. Antenna with 2 or 3 sensilla, each bearing spinule. Occipital setal row with 4–6 setae (0.06–0.08 mm long); inner and outer setae simple to denticulate, otherwise bifid, base ~0.75 length of seta. First setal row on vertex with 2 simple to denticulate setae, 0.07–0.08 mm long. Second setal row on vertex with 4 simple setae, 0.09–0.13 mm long. Setae ventral to antenna level simple, 0.08–0.14 mm long. Clypeus with transverse row of 4 setae, inner setae shorter than outer setae, 0.06–0.10 mm long. Labrum small, short (breadth ~2X length). Labrum with 4 sensilla and 2 setae on dorsal surface of each half and apex with 6 sensilla on each half. Each half of epipharynx with 3–5 isolated. Straight medial portion of mandible with 2–5 teeth that decrease in size dorsally. Maxilla with apex conical, palpus peg-like with 5 sensilla, each bearing one spinule. Galea conical with 2 apical sensilla, each bearing one spinule. Labium with patch of spinules dorsal to palpus, in short rows of 2–3. Labial palpus slightly elevated with 5 sensilla, each bearing one spinule. Body. Spiracles small, first spiracle larger than others. Integument with fine rugae throughout. Body setae of 2 types. Simple setae (0.04–0.14 mm long) arranged in transverse row of 6–10 on ventral surface of each thoracic somite and on each of 3 anterior abdominal somites, some with short denticulate tips. Bifid setae (0.06–0.11 mm long) occur elsewhere, base ~0.5X length, some with bases ;0.75X (0.08–0.10 mm long) on thoracic dorsum posterior to head capsule.

Length. 3.7–3.8 mm.

Type Material

Holotype worker. Brazil. Parana State. 4 km North of Curitiba. Trager. Museu de Zoologia da Universidade de Sao Paulo.

References