Strumigenys eggersi

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Strumigenys eggersi
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Hymenoptera
Family: Formicidae
Subfamily: Myrmicinae
Tribe: Attini
Genus: Strumigenys
Species: S. eggersi
Binomial name
Strumigenys eggersi
Emery, 1890

Pyramica eggersi casent0103845 profile 1.jpg

Pyramica eggersi casent0103845 dorsal 1.jpg

Specimen Label

An unusual Strumigenys in its tolerance for its tolerance of relatively dry conditions. Strumigenys eggersi can inhabit a wide range of habitats, e.g., forests, thickets, gardens.

Identification

Bolton (2000) - A member of the gundlachi-complex in the Strumigenys gundlachi group. Among the species closest related to Strumigenys gundlachi, eggersi is isolated by the characters in its description. It separates from Strumigenys denticulata, with which it shares the characters of extreme reduction or absence of postpetiolar appendages, by its shorter mandibles (MI 58 - 65 as opposed to MI 72 - 85 in denticulata), presence of a pair of standing hairs anteriorly on the pronotum, and more strongly sculptured gaster. Pyramica eggersi and P. gundlachi are the only species of the gundlachi-group to have been recorded from the U.S.A., where they are apparently restricted to Florida (Brown, 1960a; D. R. Smith, 1979; Deyrup, Johnson, et al., 1989).

Longino (Ants of Costa Rica) - Mandibles in full-face view linear, elongate and narrow; leading edge of scape with freely projecting hairs; inner margin of mandible without a tooth or distinctly enlarged denticle at or near the midlength; labral lobes short, trigger hairs at apices of lobes long; apical fork of mandible small, with two tiny intercalary denticles; mandibles straight, with weakly convex inner borders, each bearing 4-8 minute denticles on distal 1/3 to 1/2; spongiform appendages of petiole and postpetiole obsolete; first gastral tergum superficially reticulate-punctulate and opaque in front, becoming indefinitely shagreened and weakly shining behind.

Keys including this Species

Distribution

A common species in Florida, where it has been introduced, as far north as Union County. Pest status: none. First published Florida record: Brown 1960. (Deyrup, Davis & Cover, 2000.)

Distribution based on Regional Taxon Lists

Indo-Australian Region: Philippines.
Nearctic Region: United States.
Neotropical Region: Barbados, Belize, Bolivia, Brazil, Colombia, Costa Rica, Cuba, Dominican Republic, Ecuador, Greater Antilles, Grenada, Guadeloupe, Guatemala, Haiti, Honduras, Lesser Antilles (type locality), Mexico, Paraguay, Peru, Puerto Rico, Saint Lucia, Trinidad and Tobago, Venezuela.


Distribution based on AntMaps

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Distribution based on AntWeb specimens

Check data from AntWeb

Biology

Deyrup (1997) - Among the snap-trap ants this is an unusually drought-tolerant species that also thrives in disturbed conditions. The queens are often relatively abundant, giving the impression that this species lives in small colonies that produce many new queens that can found new colonies. This would be a useful adaptation for living in frequently disturbed habitats, where occupied nest sites are often destroyed and new ones created.

Regional Information

Caribbean

Brown (1960) - Weber found specimens in a compost heap in the Botanical Garden at Roseau, Dominica, and in an island of vegetation growing in the Pitch Lake of Trinidad; also on Trinidad, he took a sample from low-growing epiphytes in second-growth forest. Kempf sifted specimens from humus in Sao Paulo. Indications are that this species can stand more dryness than many dacetines, and its presence in many culture areas suggests that it is spreading rapidly through nursery stock transport and other human commerce.

Costa Rica

Longino (Ants of Costa Rica) - In Costa Rica this species appears rare, although my collecting has not emphasized dry and/or synanthropic habitats. I have encountered it in Winkler samples from Finca La Pacifica (riparian forest in seasonally dry region), and La Selva Biological Station (lowland rainforest).

Florida (USA)

Deyrup, Davis & Cover (2000) - In Florida this species is found in both moist and dry woods, as well as shaded yards and gardens. Nests are in leaf litter, or in hollow twigs or nuts in the litter. The species Strumigenys eggersi and Strumigenys emmae are the only dacetine ants that are commonly found in dry and mesic habitats of south and central Florida. There is little evidence that native dacetines were ever common in these areas, but if these two exotics continue their northward expansion we may be able to get some idea of their effect on native ants, since we have records of hundreds of litter samples from north Florida. These species are probably more or less specialized predators on entomobryiid Collembola. If they have not had an impact by reducing or replacing the populations of native predators of Collembola in south Florida, they must be a novel predator of the Collembola themselves in this area.

Philippines

General (2017) reports this species from an urban university campus in the Philippines, possibly introduced by trade in potted ornamental plants. He also notes that there is an unconfirmed report of its presence in Singapore (D. Booher, personal communication). The distribution of this species in the Philippines and its ecological impact there are unknown.

Castes

Worker

Queen

Nomenclature

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

  • eggersi. Strumigenys eggersi Emery, 1890b: 69, pl. 7, fig. 9 (w.q.) ANTILLES. Combination in S. (Pyramica): Brown, 1948e: 110; in Pyramica: Bolton, 1999: 1673; in Strumigenys: Baroni Urbani & De Andrade, 2007: 119. See also: Brown, 1960b: 46; Bolton, 2000: 184.

Unless otherwise noted the text for the remainder of this section is reported from the publication that includes the original description.

Description

Worker

Bolton (2000) - TL 1.6 - 2.0, HL 0.40 - 0.45, HW 0.32 - 0.37, CI 81 - 86, ML 0.23 - 0.28, MI 58 - 65, SL 0.20 - 0.24, SI 58 - 64, PW 0.20 - 0.23, AL 0.40 - 0.46 (20 measured). Characters of gundlachi complex; see also notes under Strumigenys gundlachi. Inner margin of mandible feebly convex, with 4 - 8 preapical small denticles on the distal one-third to one-half of the length. Dorsum of pronotum with a single pair of erect hairs (as well as the humeral pair), located on anterior half, usually between the humeral pair. Pair of mesonotal erect hairs short and stiff. On postpetiole ventral spongiform appendage vestigial to absent; lateral lobe absent or at most represented by a narrow marginal non-spongiform carina. First gastral tergite strongly reticulate to reticulate-punctate basally; this sculpture may cover the entire sclerite or tend to diminish in intensity posteriorly.

Type Material

Bolton (2000) - Syntype workers and queens, ANTILLES IS: St Thomas I . (Eggers) (Naturhistorisches Museum Wien, Vienna, Museu de Zoologia da Universidade de Sao Paulo, National Museum of Natural History) [examined].

References

Emery (Hymenoptera: Formicidae). Philippine Entomologist 31: 73-78.