Strumigenys

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Strumigenys
Strumigenys abdera casent0005465 profile 1.jpg
Strumigenys abdera worker
Scientific classification OOjs UI icon edit-ltr.svg
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Hymenoptera
Family: Formicidae
Subfamily: Myrmicinae
Tribe: Attini
Genus: Strumigenys
F. Smith, 1860
Type species
Strumigenys mandibularis
F. Smith, 1860
Diversity [1]
> 880 species
Synonyms
List of synonyms
  • AsketogenysBrown, 1972
    BorgmeieritaBrown, 1953
    CephaloxysSmith, F., 1865
    ChelystrumaBrown, 1950
    CladarogenysBrown, 1976
    CodiomyrmexWheeler, W.M., 1916
    CodioxenusSantschi, 1931
    DorisidrisBrown, 1948
    DysedrognathusTaylor, 1968
    EneriaDonisthorpe, 1948
    EpitritusEmery, 1869
    GlamyromyrmexWheeler, W.M., 1915
    GymnomyrmexBorgmeier, 1954
    KyidrisBrown, 1949
    LabidogenysRoger, 1862
    MiccostrumaBrown, 1948
    NeostrumaBrown, 1948
    PentastrumaForel, 1912
    PlatystrumaBrown, 1953
    PolyhomoaAzuma, 1950
    ProscopomyrmexPatrizi, 1946
    PyramicaRoger, 1862
    QuadristrumaBrown, 1949
    SerrastrumaBrown, 1948
    SmithistrumaBrown, 1948
    TingimyrmexMann, 1926
    TrichoscapaEmery, 1869
    WeberistrumaBrown, 1948
    WessonistrumaBrown, 1948

Strumigenys is a genus of ants in the subfamily Myrmicinae. It is a widespread, speciose genus of small ants with cryptic lifestyles that are predators of small arthropod prey.

Contents

Biology

Nesting and Foraging

Strumigenys are small ants with mainly predatory diets, though they may occasionally feed on sugar sources such as extrafloral nectaries as well. [2] Members of the genus are specialist predators of small arthropods. The most common prey items are springtails but a wide variety of other small arthropod prey have been documented as well. [2] [3] [4]

Most forage solitarily for small prey among organic debris like leaf litter and dead wood, though some are known to forage arboreally and some intranidally. [2] [5] [6] [7] Nesting habits are various, nests are most commonly found in soil, under rocks, and in or under dead wood and logs, but have also been found under bark or among epiphytes. [3] [8] Some nest alongside other ants as xenobiosis or social parasitism. [6] [7] [9] [10]

Relationships with other ants

A notable aspect of the genus' biology is its interactions with other ants. Multiple species of Strumigenys have been documented living alongside other ants. These symbioses range from social parasitism to proposed mutualism. Some representative cases of these various relationships are included here.

Strumigenys maynei lives in the nests of the much larger ponerine ant Platythyrea conradti, and has been observed predating on arthropods within the Platythyrea nest and may defend the nest against other ants. [6] A similar relationship is also known in Strumigenys arizonica, which obligately lives within the nests of the fungus-farming ant Trachymyrmex arizonensis, and feeds on springtails within the nests. [7] The former case has been proposed as a mutualism while the latter may be mutualism or commensalism.

Other species, such as Strumigenys pergandei, are more facultative in their relationships with other ants. S. pergandei is often found within the nests of larger ants such as Aphaenogaster , Camponotus , and Formica , but can also be found nesting independently under rocks and in leaf litter. [9] [11]

Strumigenys yaleogyna is an inquiline parasite that lives in the nest of its free-living host species, Strumigenys loriae. S. yaleogyna workers have been observed foraging, attempting hunting, and tending coccids but are outperformed by their hosts, showing a reduced hunting ability associated with this form of parasitism. [3]

Strumigenys xenos is a workerless inquiline parasite of the closely-related free-living species Strumigenys perplexa. It produces no worker caste of its own and relies on S. perplexa workers to care for it. The S. xenos queen is attractive to the S. perplexa workers and they will constantly tend to it and evacuate it in response to threats. [10]

Trap-jaw mandibles

Trap-jaw mouthparts of Strumigenys ayersthey, with the clypeus, mandibles, and labrum highlighted Strumigenys ayersthey (10.3897-zookeys.1036.62034) Figure 5.jpg
Trap-jaw mouthparts of Strumigenys ayersthey , with the clypeus, mandibles, and labrum highlighted

Mouthpart morphology is quite variable and diverse within Strumigenys, which has contributed to a complicated taxonomic history. [9] Many members of the genus are trap-jaw ants, with modified mouthparts that assist in hunting. The trap-jaw mouthparts involve a modified labrum which interacts with a basal mandibular process to lock the mandibles open. From this position the mandibles can snap shut with considerable speed once triggered, which is achieved with sensory "trigger" setae. [8] [12] Mandible morphology within the genus has been categorized into gripping, short-trap, or long-trap mandibles based on the length of the mandible and whether a trap-jaw latch mechanism is present. Short-trap and long-trap mandibles have both independently evolved from a gripping ancestral form multiple times, as well as transitions to short-trap from long-trap lineages. [12]

Strumigenys mandible diversity Strumigenys (10.3897-zookeys.970.54958) Figure 14.jpg
Strumigenys mandible diversity

Distribution

The genus is broadly distributed with most of its diversity occurring in tropical rainforests around the world, but a number of species occur in more Mediterranean or temperate climates. [4] In tropical regions, Strumigenys is often an abundant component of the litter community. [13]

In terms of regional diversity, the known fauna of Strumigenys is distributed as follows: 139 species are known from the Afrotropical region, 60 from the Australasian region, 258 from the Indo-Australian region, 94 from the Malagasy region, 59 from the Nearctic region, 214 from the Neotropical region, 97 from the Oriental region, and 81 from the Palearctic region. [14]

Identification and taxonomy

One of the most distinctive characters of the genus Strumigenys is the presence of spongiform tissue — a "honeycomb-like", foveolate extension of the cuticle — on the anterior segments of the metasoma in the majority of species, though spongiform tissue is convergently present in two unrelated ant genera, Dacetinops and Tetheamyrma. [8] [15] In Strumigenys this spongiform tissue is associated with exocrine glands of an unknown function. [15] Strumigenys often have modified setae, such as bent, spatulate, or bulbous, among various other forms. The antennae have reduced segmentation, with four to six antennomeres, and the palps are also reduced with one-segmented labial palps and zero or one-segmented maxillary palps. [8]

The genus Strumigenys is speciose with 884 currently recognized species. Since the establishment of the genus in 1860 by Frederick Smith, it has accumulated twenty-eight generic synonyms. [16] [17] One of the largest and most notable of these is the former genus Pyramica, which has been moved in and out of synonymy with Strumigenys numerous times, with arguments relying largely on the morphology and function of the mandibles and labrum, before the rise of genetic analysis and phylogenetic capabilities. [9] [18]

Selected species

The genus contains over 880 species. [1] They include:

See also

References

  1. 1 2 Bolton, B. (2025). "Strumigenys". AntCat. Retrieved 18 March 2025.
  2. 1 2 3 Lach, Lori; Parr, Catherine L.; Abbott, Kirsti L., eds. (2009). Ant ecology. Oxford: Oxford University Press. ISBN   978-0-19-172019-2.
  3. 1 2 3 Hölldobler, Bert; Wilson, Edward O. (1990). The ants. Cambridge, Mass: Belknap Press of Harvard University Press. ISBN   978-0-674-04075-5.
  4. 1 2 Bolton, Barry (1998). "Monophyly of the dacetonine tribe-group and its component tribes (Hymenoptera: Formicidae)". Bulletin of the Natural History Museum, Entomology Series. 67 (1): 65–78. Retrieved 21 February 2022.
  5. ↑ Brown, William L.; Wilson, Edward O. (December 1959). "The Evolution of the Dacetine Ants". The Quarterly Review of Biology. 34 (4): 278–294. doi:10.1086/402828. ISSN   0033-5770.
  6. 1 2 3 Parmentier, Thomas; Yéo, Kolo; Dekoninck, Wouter; Wenseleers, Tom (2017-02-06). "An apparent mutualism between Afrotropical ant species sharing the same nest". Behavioral Ecology and Sociobiology. 71 (3): 46. Bibcode:2017BEcoS..71...46P. doi:10.1007/s00265-017-2274-8. ISSN   1432-0762.
  7. 1 2 3 Gray, K. W.; Cover, S. P.; Johnson, R. A.; Rabeling, C. (2018-08-01). "The dacetine ant Strumigenys arizonica, an apparent obligate commensal of the fungus-growing ant Trachymyrmex arizonensis in southwestern North America". Insectes Sociaux. 65 (3): 401–410. doi:10.1007/s00040-018-0625-8. ISSN   1420-9098.
  8. 1 2 3 4 Bolton, Barry (1999-11-01). "Ant genera of the tribe Dacetonini (Hymenoptera: Formicidae)". Journal of Natural History. 33 (11): 1639–1689. Bibcode:1999JNatH..33.1639B. doi:10.1080/002229399299798. ISSN   0022-2933.
  9. 1 2 3 4 Ellison, Aaron M. (2014). Field Guide to the Ants of New England. Cumberland: Yale University Press. ISBN   978-0-300-18890-5.
  10. 1 2 Brown, William L. (1955-09-01). "The first social parasite in the ant tribe dacetini". Insectes Sociaux. 2 (3): 181–186. doi:10.1007/BF02224379. ISSN   1420-9098.
  11. ↑ Brown, William L. (1963). "The Ant Genus Smithistruma: A First Supplement to the World Revision (Hymenoptera: Formicidae)". Transactions of the American Entomological Society (1890-). 89 (3/4): 183–200. ISSN   0002-8320. JSTOR   25077859.
  12. 1 2 Booher, Douglas B.; Gibson, Joshua C.; Liu, Cong; Longino, John T.; Fisher, Brian L.; Janda, Milan; Narula, Nitish; Toulkeridou, Evropi; Mikheyev, Alexander S.; Suarez, Andrew V.; Economo, Evan P. (2021-03-02). "Functional innovation promotes diversification of form in the evolution of an ultrafast trap-jaw mechanism in ants". PLOS Biology. 19 (3) e3001031. doi: 10.1371/journal.pbio.3001031 . ISSN   1545-7885. PMC   7924744 . PMID   33651798.
  13. ↑ Silva, Thiago Sanches Ranzani; Chaul, Júlio Cezar Mário; Feitosa, Rodrigo Machado (2022). "Lectotype designation and redescription of four commonly collected Neotropical species of Strumigenys (Hymenoptera: Formicidae)". European Journal of Taxonomy (798): 103–126. Bibcode:2022EJTax.798.1673S. doi:10.5852/ejt.2022.798.1673.
  14. ↑ AntWiki: Genus Strumigenys
  15. 1 2 Wang, Chu; Chung, Fu-Ya; Lin, Chung-Chi; Gibson, Joshua C.; McGuire, Sara; Suarez, Andrew V.; Billen, Johan (2023-03-01). "The spongiform tissue in Strumigenys ants contains exocrine glands". Arthropod Structure & Development. 73 101246. Bibcode:2023ArtSD..7301246W. doi:10.1016/j.asd.2023.101246. ISSN   1467-8039. PMID   36822131.
  16. ↑ Bolton, B. (2025). "Strumigenys". AntCat. Retrieved 11 November 2025.
  17. ↑ Baroni Urbani, Cesare; de Andrade, Maria Lourdes (2007-11-28). "The ant tribe Dacetini: limits and constituent genera, with descriptions of new species (Hymenoptera, Formicidae)". Annali del Museo Civico di Storia Naturale Giacomo Doria. 99: 1–191 – via BioStor.
  18. ↑ Bolton, Barry (2000). The ant tribe Dacetini: with a revision of the Strumigenys species of the Malagasy Region by Brian L. Fisher and a revision of the Austral epopostrumiform gewnera by Steven O. Shattuck. Memoirs of the American Entomological Institute. Gainesville, FL: American Entomolog. Inst. ISBN   978-1-887988-09-4.
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