Solenopsis papuana

This species was found in Hawaiʻi in 1967 and is now widespread in mesic to wet forest ecosystems across at least several islands (Huddleston and Fluker, 1968; Gillespie and Reimer, 1993; Reimer, 1994). In these ecosystems S. papuana is generally rare on vegetation distant from the ground (Krushelnycky, 2015), but has occasionally been observed foraging up to a height of at least two meters on tree trunks. More commonly, it attains high densities and is most active in the soil and leaf litter (Ogura-Yamada and Krushelnycky, 2016, unpub. data). Krushelnycky et al (2017) performed a field experiment to determine potential effects of these ants on populations of picture wing flies. Suppression of S. papuana in field plots resulted in a 2.4-fold increase, on average, in the rate of successful development from egg to adult in the Hawaiian picture-winged Drosophila fly D. crucigera. Six species of endangered picture-winged Drosophila species occur or were historically collected in the Waiʻanae Mountains of Oʻahu in the same or similar habitats represented by the field sites, and were therefore considered potentially threatened by S. papuana.

Identification
Within the Australian fauna, Heterick (2019) provides the following notes: Solenopsis papuana was identiﬁed using a combination of Emery's original description (Emery 1900) and AntWeb images. Images of both sets of species and their accompanying labels are available on AntWeb (CASENT0872757 for a Solenopsis papuana queen and CASENT087757 for a Solenopsis papuana worker). The Queensland Solenopsis specimens, collected in Centenary Lakes in Cairns, have paraclypeal teeth in addition to the normal clypeal teeth. This feature is lacking from most workers imaged on AntWeb (including syntypes) but can clearly be seen in an identical worker collected on Oahu, Hawaii and identiﬁed by P. Krushelnycky as Solenopsis papuana. Another, similar worker identiﬁed by Krushelnycky as S. papuana and also collected on Oahu appears to lack paraclypeal teeth. Apparently, this feature is variable, as is the colour in this species (Wilson & Taylor 1967).

Distribution based on Regional Taxon Lists
Australasian Region: Australia, New Caledonia. Indo-Australian Region: Fiji, Hawaii, Marshall Islands, Micronesia (Federated States of), New Guinea, Northern Mariana Islands, Palau, Samoa, Solomon Islands, Tonga, Wallis and Futuna Islands. Malagasy Region: Seychelles.

Worker
Workers, queens and males have been described.

Nomenclature

 *  papuana. Solenopsis papuana Emery, 1900c: 330 (w.q.) NEW GUINEA. Senior synonym of cleptis, dahlii, vitiensis: Wilson & Taylor, 1967: 60.
 * dahlii. Solenopsis dahlii Forel, 1901b: 14 (w.q.m.) NEW GUINEA (Bismarck Archipelago). Junior synonym of papuana: Wilson & Taylor, 1967: 60.
 * cleptis. Solenopsis cleptis Mann, 1919: 330 (w.) SOLOMON IS. Junior synonym of papuana: Wilson & Taylor, 1967: 60.
 * vitiensis. Solenopsis cleptis var. vitiensis Mann, 1921: 444 (w.) FIJI IS. Junior synonym of papuana: Wilson & Taylor, 1967: 60.