Strumigenys rostrata

Nests in both soil and wood, and is commonly found nesting in nuts (Booher et al., 2017).

Identification
Bolton (2000) - A member of the Strumigenys rostrata-group. Of the seven species in the group Strumigenys chiricahua and Strumigenys hyalina are immediately separated as they are the only ones to have a mandibular diastema that is decidedly longer than the basal tooth. Strumigenys californica is isolated by the presence of distinctly sculptured zones at the apices of the first gastral tergite and sternite, these zones remaining smooth and polished in all other species. In the relatively large rostrata (HL 0.61-0.72, HW 0.42-0.47) the dentition is coarse, with teeth 6 and 7 enlarged (see above), and its specialised projecting pilosity is characteristic: stout simple hairs are present in apicoscrobal position, at pronotal humerus and on mesonotum (one pair). The remaining three species, Strumigenys arizonica, Strumigenys bunki, Strumigenys carolinensis, average smaller (HL 0.54-0.64, HW 0.37-0.41) and have much smaller finer dentition (in particular teeth 6 and 7 are insignificant), nor do they have pilosity like rostrata at all the points mentioned; in particular all three lack an apicoscrobal hair. S. carolinensis has a pair of long flagellate hairs on the mesonotum, not developed in arizonica and bunki where mesonotal hairs are simple or absent. These last two species separate on relative development of spongiform tissue (see key) and on the complete lack of mesonotal standing hairs but presence of long fine gastral pilosity in bunki. Compared to this arizonica has a single pair of short simple erect hairs on the mesonotum and the first gastral tergite is sparsely clothed with very short stubbly simple hairs.

Flagellate hairs that project from the dorsal (outer) surface of the hind basitarsus are absent in rostrata and arizonica, always present in carolinensis. In bunki some specimens show such hairs, others do not. Because most bunki I have seen have been badly treated and poorly mounted I suspect that these fine and delicate hairs have been mostly stripped away and that they will always be present in fresh material.

Distribution based on Regional Taxon Lists
Nearctic Region: United States.

Biology
Wesson and Wesson (1939) - Jackson, Pike, Ross and Scioto counties, Ohio. We have taken this species in both soil and wood, sometimes in decidedly dry situations. Three colonies were found in a hickory log, the decaying portion of a large elm tree in which also lived a colony of Aphaenogaster tennesseensis, and in a crevice in a stump in a wooded pasture, a few centimeters from another colony of A. tennesseensis. Three colonies were taken on the edge of some dry oak woods, all in or on the humus just under the dry oak leaves, which, with some grass and herbs, covered the ground. The nesting site of one was a rotten hickory nut; the second was in some cavities in a small decayed stick; the third was living in a crevice of a partly buried board. Workers were found under the leaves in the vicinity of the nests, presumably foraging. They were not apparently associated with any other ants. A few dead springtails were found in one of the nests. On one occasion a colony of S. rostrata was found living in a chamber in dry soil under a stone. Under the stone there also ran a few galleries of Lasius umbratus.

A S. rostrata colony was transferred to an artificial nest for observation. While employing the same general methods of hunting springtails as the other species studied, the rostrata workers differ in being more active. Instead of crouching in one spot awaiting the advent of a springtail, they spend most of their foraging time moving over the debris in the nest. When a worker scents a springtail 2 or 3 mm. away, she crouches, and, without touching it, tries various avenues of approach until she is so close that her mandibles almost touch the springtail. Then, head lowered, mandibles closed, antennae partially folded, she waits until the springtail, unaware of her presence, walks against her head. Then, seizing it with a quick snap of her mandibles, she quickly dispatches it with her sting. If, on the other hand, the springtail moves away from the ant, the latter repeats her approach. If the springtail shows no inclination to move within a few minutes, the ant often acts as though impatient, and tries to examine it with her antennae, or to take it in her mandibles.

Nomenclature

 *  rostrata. Strumigenys rostrata Emery, 1895c: 329, pl. 8, figs. 23, 24 (w.q.m.) U.S.A. Wheeler, G.C. & Wheeler, J. 1955a: 144 (l.). Combination in S. (Cephaloxys): Emery, 1924d: 325; in S. (Trichoscapa): Smith, M.R., 1943f: 307; Creighton, 1950a: 309; in Smithistruma: Smith, M.R., 1951a: 828; Brown, 1953g: 84; in Pyramica: Bolton, 1999: 1673; in Strumigenys: Baroni Urbani & De Andrade, 2007: 127. See also: Wilson, 1954: 485; Bolton, 2000: 129.

Worker
TL 2.4-2.8, HL 0.61-0.72, HW 0.42-0.47, CI 66-68, ML 0.10-0.14, MI 17-20, SL 0.28-0.32, SI 67-72, PW 0.28-0.32, AL 0.61-0.69 (30 measured; incorporating maximum and minimum dimensions of Brown, 1953a). Basal lamella longer than any of the teeth, feebly recurved; without a diastema between lamella and basal tooth. Teeth 1-5 strongly developed, coarse and conical; teeth 3 and 5 are longer than 4; tooth 3 is longest on the margin but only slightly more so than tooth 5. Teeth 6-7 also strongly developed and conical, shorter than 1-5 but not much shorter than 4, so that in full-face view the entire visible margin has a coarsely 7-dentate appearance. Anterior clypeal margin extremely shallowly concave. Eye with 4-5 ommatidia in the longest row. Basigastral costulae numerous and sharply defined, extending about one-quarter the length of the tergite. Apicoscrobal hair fairly stout and curved, blunt or truncated apically. Cephalic dorsum with 4 curved suberect hairs close to occipital margin. Pronotal humeral hair stout, straight or only very shallowly curved; a single similar pair on the mesonotum. First gastral tergite with standing filiform hairs arranged in a basal and an apical transverse row; tergite between these rows usually without standing pilosity, rarely with a few hairs present. Dorsal (outer) surfaces of middle and hind basitarsi without projecting long fine flagellate hairs.

Type Material
Syntype workers, queens and male, U.S.A. District of Columbia, Washington (Pergande) [examined].

References based on Global Ant Biodiversity Informatics

 * Brown W. L., Jr. 1953. Revisionary studies in the ant tribe Dacetini. Am. Midl. Nat. 50: 1-137.
 * Carroll T. M. 2011. The ants of Indiana (Hymenoptera: Formicidae). Master's Thesis Purdue university, 385 pages.
 * Colby, D. and D. Prowell. 2006. Ants (Hymenoptera: Formicidae) in Wet Longleaf Pine Savannas in Louisiana. Florida Entomologist 89(2):266-269
 * Coovert G. A. 2005. The Ants of Ohio (Hymenoptera: Formicidae). Ohio Biological Survey, Inc. 15(2): 1-207.
 * Coovert, G.A. 2005. The Ants of Ohio (Hymenoptera: Formicidae) Ohio Biological Survey Bulletin New Series Volume 15(2):1-196
 * Dash S. T. and L. M. Hooper-Bui. 2008. Species diversity of ants (Hymenoptera: Formicidae) in Louisiana. Conservation Biology and Biodiversity. 101: 1056-1066
 * Del Toro, I. 2010. PERSONAL COMMUNICATION. MUSEUM RECORDS COLLATED BY ISRAEL DEL TORO
 * Dennis C. A. 1938. The distribution of ant species in Tennessee with reference to ecological factors. Annals of the Entomological Society of America 31: 267-308.
 * Deyrup, M. 2003. An updated list of Florida ants (Hymenoptera: Formicidae). Florida Entomologist 86(1):43-48.
 * Deyrup, M. and S. Cover. 2009. Dacetine Ants in Southeastern North America (Hymenoptera: Formicidae). Southeastern Naturalist 8(2):191-212
 * Dubois, M.B. and W.E. Laberge. 1988. An Annotated list of the ants of Illionois. pages 133-156 in Advances in Myrmecology, J. Trager
 * Forster J.A. 2005. The Ants (hymenoptera: Formicidae) of Alabama. Master of Science, Auburn University. 242 pages.
 * Frye J. A., T. Frye, and T. W. Suman. 2014. The ant fauna of inland sand dune communities in Worcester County, Maryland. Northeastern Naturalist, 21(3): 446-471.
 * General D. M., and L. C. Thompson. 2011. New Distributional Records of Ants in Arkansas for 2009 and 2010 with Comments on Previous Records. Journal of the Arkansas Academy of Science 65: 166-168.
 * Guénard B., K. A. Mccaffrey, A. Lucky, and R. R. Dunn. 2012. Ants of North Carolina: an updated list (Hymenoptera: Formicidae). Zootaxa 3552: 1-36.
 * Hill J. G., K. S. Summerville, and R. L. Brown. 2008. Habitat Associations of Ant Species (Hymenoptera: Formicidae) in a Heterogeneous Mississippi Landscape. Environ. Entomol. 37(2): 453-463.
 * Ipser R. M. 2004. Native and exotic ants (Hymenoptera: Formicidae) of Georgia: Ecological Relationships with implications for development of biologically-based management strategies. Doctor of Philosophy thesis, University of Georgia. 165 pages.
 * Ivanov K. 2019. The ants of Ohio (Hymenoptera, Formicidae): an updated checklist. Journal of Hymenoptera Research 70: 65–87.
 * Ivanov K., L. Hightower, S. T. Dash, and J. B. Keiper. 2019. 150 years in the making: first comprehensive list of the ants (Hymenoptera: Formicidae) of Virginia, USA. Zootaxa 4554 (2): 532–560.
 * Kjar D. 2009. The ant community of a riparian forest in the Dyke Marsh Preserve, Fairfax County, Virginiam and a checklist of Mid-Atlantic Formicidae. Banisteria 33: 3-17.
 * Kjar D., and E. M. Barrows. 2004. Arthropod community heterogeneity in a mid-Atlantic forest highly invaded by alien organisms. Banisteria 23: 26-37.
 * Kjar D., and Z. Park. 2016. Increased ant (Hymenoptera: Formicidae) incidence and richness are associated with alien plant cover in a small mid-Atlantic riparian forest. Myrmecological News 22: 109-117.
 * Lessard J. P., R. R. Dunn, C. R. Parker, and N. J. Sanders. 2007. Rarity and Diversity in Forest Ant Assemblages of Great Smoky Mountains National Park. Southeastern Naturalist 1: 215-228.
 * Lynch J. F. 1988. An annotated checklist and key to the species of ants (Hymenoptera: Formicidae) of the Chesapeake Bay region. The Maryland Naturalist 31: 61-106
 * Lynch J. F., and A. K. Johnson. 1988. Spatial and temporal variation in the abundance and diversity of ants (Hymenoptera: Formicidae) in the soild and litter layers of a Maryland forest. American Midland Naturalist 119(1): 31-44.
 * MacGown J. A., J. G. Hill, R. L. Brown, T. L. Schiefer, J. G. Lewis. 2012. Ant diversity at Noxubee National Wildlife Refuge in Oktibbeha, Noxubee, and Winston Counties, Mississippi. Mississippi Agricultural and Forestry Experiment Station Bulletin 1197: 1-30
 * MacGown J. A., J. G. Hill, and M. Deyrup. 2009. Ants (Hymenoptera: Formicidae) of the Little Ohoopee River Dunes, Emanuel County, Georgia. J. Entomol. Sci. 44(3): 193-197.
 * MacGown J. A., J. G. Hill, and R. L. Brown. 2010.  Native and exotic ant in Mississippi state parks.  Proceedings:  Imported Fire Ant Conference, Charleston, South Carolina, March 24-26, 2008: 74-80.
 * MacGown J. A., and R. L. Brown. 2006. Survey of the ants (Hymenoptera: Formicidae) of the Tombigbee National Forest in Mississippi. Journal of the Kansas Entomological Society 79(4):325-340.
 * MacGown J.A., Hill J.G. and Skvarla M. 2011. New Records of Ants (Hymenoptera: Formicidae) for Arkansas with a Synopsis of Previous Records. Midsouth Entomologist. 4: 29-38
 * MacGown, J. and J.G. Hill. Ants collected at Palestinean Gardens, George County Mississippi.
 * MacGown, J.A and J.A. Forster. 2005. A preliminary list of the ants (Hymenoptera: Formicidae) of Alabama, U.S.A. Entomological News 116(2):61-74
 * MacGown, J.A. and JV.G. Hill. Ants of the Great Smoky Mountains National Park (Tennessee and North Carolina).
 * MacGown, J.A. and R.L. Brown. 2006. Survey of the ants (Hymenoptera: Formicidae) of the Tombigbee National Forest in Mississippi. Journal of the Kansas Entomological Society 79(4):325-340.
 * MacGown, J.A., J.G. Hill, R.L. Brown and T.L. 2009. Ant Diversity at Noxubee National Wildlife Refuge in Oktibbeha, Noxubee, and Winston Counties, Mississippi Report #2009-01. Schiefer. 2009.
 * MacGown, J.A., R.L. Brown and J.G. Hill. 2005. An Annotated List of the Pyramica (Hymenoptera: Formicidae: Dacetini) of Mississippi. Journal of the Kansas Entomological Societ 78 (3):285-289
 * MacGown. J. 2011. Ants collected during the 25th Annual Cross Expedition at Tims Ford State Park, Franklin County, Tennessee
 * MacKay W. P. and Anderson R. S. 1993. New distributional records for the ant genus Smithistruma (Hymenoptera: Formicidae) in southern United States. The Southwestern Naturalist 38: 388-389
 * Macgown J. A., S. Y. Wang, J. G. Hill, and R. J. Whitehouse. 2017. A List of Ants (Hymenoptera: Formicidae) Collected During the 2017 William H. Cross Expedition to the Ouachita Mountains of Arkansas with New State Records. Transactions of the American Entomological Society, 143(4): 735-740.
 * Nuhn, T.P. and C.G. Wright. 1979. An Ecological Survey of Ants (Hymenoptera: Formicidae) in a Landscaped Suburban Habitat. American Midland Naturalist 102(2):353-362
 * O'Keefe S. T., J. L. Cook, T. Dudek, D. F. Wunneburger, M. D. Guzman, R. N. Coulson, and S. B. Vinson. 2000. The Distribution of Texas Ants. The Southwestern Entomologist 22: 1-92.
 * O'Neill J.C. and Dowling A.P.G. 2011. A Survey of the Ants (hymenoptera: Formicidae) of Arkansas and the Ozark Mountains. An Undergraduate Honors, University of Arkansas. 18pages.
 * Smith M. R. 1931. A revision of the genus Strumigenys of America, north of Mexico, based on a study of the workers (Hymn.: Formicidae). Annals of the Entomological Society of America 24: 686-710.
 * Talbot M. 1957. Populations of ants in a Missouri woodland. Insectes Sociaux 4(4): 375-384.
 * Van Pelt A. F. 1966. Activity and density of old-field ants of the Savannah River Plant, South Carolina. Journal of the Elisha Mitchell Scientific Society 82: 35-43.
 * Warren, L.O. and E.P. Rouse. 1969. The Ants of Arkansas. Bulletin of the Agricultural Experiment Station 742:1-67
 * Wesson L. G., and R. G. Wesson. 1939. Notes on Strumigenys from southern Ohio, with descriptions of six new species. Psyche (Cambridge) 46: 91-112.
 * Whitcomb W. H., H. A. Denmark, A. P. Bhatkar, and G. L. Greene. 1972. Preliminary studies on the ants of Florida soybean fields. Florida Entomologist 55: 129-142.
 * Zettler J. A., M. D. Taylor, C. R. Allen, and T. P. Spira. 2004. Consequences of Forest Clear-Cuts for Native and Nonindigenous Ants (Hymenoptera: Formicidae). Ann. Entomol. Soc. Am. 97(3): 513-518.