Tetramorium cf. caespitum (Linnaeus, 1758), (Tetramorium sp. E of Schlick-Steiner et al. 2006)

Ivanov, Kaloyan, 2016, Exotic ants (Hymenoptera, Formicidae) of Ohio, Journal of Hymenoptera Research 51, pp. 203-226 : 215-216

Tetramorium cf. caespitum (Linnaeus, 1758), (Tetramorium sp. E of Schlick-Steiner et al. 2006)

Distribution in Ohio.

Statewide in Ohio. Counties: Listed for 74 of Ohio’s 88 counties in Coovert (2005); Geauga (material examined: multiple records from well-separated localities within the county [KI 1206, 1219, 1261, 1281, 1322, 1351, 1356, 1375, 1411, 1427, 1454, 1509, 1601, 1986], leg. K. Ivanov)

Where found/Habitat.

Along roadsides, in cracks in driveways, pavement and roads, under rocks and logs in open woodlands and wood edges, in grassy fields and many disturbed areas. Also in gardens, lawns and inside residences.

Origin.

Europe.

Natural history.

A temperate species commonly found in urban habitats and adjacent natural settings in Ohio. Tetramorium cf. caespitum has been continuously documented in the state since its first discovery and undoubtedly occurs in all of Ohio’s counties. In North America this species has been reported as an agricultural pest, and shown to expand into natural habitats where it displaces native ants ( Steiner et al. 2008 and references therein). Despite its wide ranging distribution it is relatively unstudied especially in its native habitats. This is a dark brown to black ant that can be identified by its 12 segmented antennae, the lateral portion of the clypeus which is raised into a sharp ridge anterior to the antennal insertion, the presence of abundant unbranched hairs on the mesosomal dorsum, and the regular longitudinal rugulation on the head behind the eyes. The East Asian Tetramorium tshushimae Emery, 1925 (known from Missouri and Illinois; Steiner et al. 2006) is smaller and typically has light colored individuals in addition to dark ones.

Pavement ant colonies are large to very large and usually monogynous. Nests are initiated by a single reproductive queen that carries out reproduction for the lifespan of the colony. In North America nuptial flights most commonly occur in mid-summer and generally one sex predominates in the reproductives produced by a particular colony ( Bruder and Gupta 1972). In spring, large-scale battles between workers from unrelated colonies commonly can be observed when pavement ants are developing their territories ( Ellison et al. 2012). This is an omnivorous species whose diet includes live and dead animal matter, seeds, plant exudates, occasional honeydew gathering, and kitchen food items ( Smith 1965). Although common in outdoor situations this species is also an abundant indoor pest in parts of eastern North America ( Klotz et al. 2008).

I have observed this species in every Ohio County in which I have had the opportunity to collect material. This is undoubtedly one of the most common ants I have encountered in the state although it is largely restricted to human-modified environments where workers are nearly ubiquitous on paved surfaces, near and inside buildings and in open grass situations (including mowed lawns). I have rarely encountered this ant in natural, relatively undisturbed, settings in Ohio. Nearly all colonies I have seen were located in open situations usually under some type of cover object, most commonly large rocks, or at the bases of grasses. Notable exceptions include two rather large colonies from northeastern Ohio, the first of which [KI 1375] was found in a naturalized open grass field at Eldon Russel Park in Geauga County and comprised a large, de-vegetated, soil mound akin to those of young Formica exsectoides Forel, 1886 colonies. The second colony [KI 2332] was found inside a very large rotten stump in the park manager’s service area of Acacia Reservation in Cuyahoga County.