Dolichoderus inermis

Identification
Color black; scapes and mesosomal dorsum with abundant delicate erect setae; dorsal and posterior faces of propodeum meeting at rounded angle and not produced as a projecting flange; face and mesosomal dorsum sublucid; pronotum transverse, with spiniform humeri (Jack Longino).

Distribution based on Regional Taxon Lists
Neotropical Region: Costa Rica.

Biology
This species is a moderately abundant element of the fauna in Corcovado National Park, but so far it is known only from Corcovado. Within Corcovado I collected it at Sirena, Los Patos, Los Planes, Cerro Rincon, and Llorona, so it is widely distributed on the Osa Peninsula. Three times I observed clusters of workers on inflorescences, once on Acanthaceae, once on Hamelia axillaris (Rubiaceae), and once on Melastomataceae. In the first two cases, the inflorescences also had abundant Membracidae and Coccoidea (scale insects). At Sirena I observed workers foraging parabiotically with Crematogaster carinata. The workers were together on low vegetation, moving together in columns and forming clumps of stationary workers. Thus D. inermis is probably parabiotic, much like Dolichoderus debilis. The workers move very slowly and seem relatively passive, in contrast to many other species of Dolichoderus that either flee or aggressively attack in response to disturbance. The workers often move with their gasters twisted laterally, a distinctive posture I have also seen in some species of Myrmelachista. (Jack Longino)

Nomenclature

 *  inermis. Dolichoderus inermis Mackay, W.P., 1993b: 63, figs. 9, 10 (w.) COSTA RICA.

References based on Global Ant Biodiversity Informatics

 * Franco W., N. Ladino, J. H. C. Delabie, A. Dejean, J. Orivel, M. Fichaux, S. Groc, M. Leponce, and R. M. Feitosa. 2019. First checklist of the ants (Hymenoptera: Formicidae) of French Guiana. Zootaxa 4674(5): 509-543.
 * Longino J. et al. ADMAC project. Accessed on March 24th 2017 at https://sites.google.com/site/admacsite/
 * Longino, J.T. 2003. The Crematogaster (Hymenoptera, Formicidae, Myrmicinae) of Costa Rica. Zootaxa 151:1-150
 * Mackay, W.P. 1993. A review of the New World ants of the genus Dolichoderus (Hymenoptera: Formicidae). Sociobiology 22(1):1-148
 * Shattuck S. O. 1994. Taxonomic catalog of the ant subfamilies Aneuretinae and Dolichoderinae (Hymenoptera: Formicidae). University of California Publications in Entomology 112: i-xix, 1-241.
 * da Silva de Oliveira A. B., and F. A. Schmidt. 2019. Ant assemblages of Brazil nut trees Bertholletia excelsa in forest and pasture habitats in the Southwestern Brazilian Amazon. Biodiversity and Conservation 28(2): 329-344.