Dolichoderus

The genus Dolichoderus has been historically treated in up to seven subgenera ^[3] or genera ^[4][5]. The ants of the former Neotropical genus Monacis were revised in 1959 by Kempf^[6]. However, Brown in 1973 and G. C. Wheeler and J. Wheeler in 1973 and 1976 considered both Monacis and Hypoclinea to be junior synonyms of Dolichoderus.^[7]. Subsequently, the genera Hypoclinea, Monacis, and Monoceratoclinea were revived by Hölldobler and Wilson^[8]. Most recently, Shattuck^[5] again synonymized all previous genera and subgenera under the single name Dolichoderus, which remains the current valid circumscription^[9].

The type species is Dolichoderus attelaboides (Fabricius, 1775). Worker ants in this genus have a body length that is typically about four millimetres and can be recognised by their thick, inflexible and strongly sculptured integument. There is a flange on the underside of the head near the base of the mandibles which is tooth-like in some species. The longitudinal suture in the central plate of the metathorax is deeply impressed. The propodeum or first abdominal segment has the posterior face distinctly concave when viewed from the side. The gaster and mesosoma are separated by a single segment, the petiole. The orifice of the cloaca is a horizontal slit rather than a circular opening^[5]. It may be surrounded by a few rather stiff erect bristles.^[10]

Members of this genus are found worldwide, except for the continent of Africa; North America west of the Rocky Mountains, and the Southern Cone of Australia^[5][11].

Colonies are of varying sizes and are constructed in the soil, in curled leaves, in the hollow stems of plants and in cartons which are formed by the ants chewing wood and mixing the product with secretions in a similar way to that used by wasps to build their nests. Some species are very versatile, with Dolichoderus pustulatus nesting underground in northern parts of the United States while living wholly in trees in the south.^[10] The workers seek out and tend sap-sucking insects such as aphids and scale insects that excrete honeydew and they also feed on small arthropods. Members of the Dolichoderus cuspidatus species group are unique among ants in being nomadic herbivores (i.e., not building permanent nests) which are obligate mutualists with coevolved pseudococcid mealybugs^[12]. Some species emit a pungent smelling fluid like other members of the subfamily. Several species are polygynous with several queens in one nest^[12][13]. It is also possible that D. taschenbergi may be a temporary social parasite with D. plagiatus as host.^[14]