Diacamma scalpratum

Peeters, Heraty & Wiwatwitaya (2015) excavated four complete colonies of D. scalpratum from northern Thailand. Colonies were plentiful and easy to find in a small patch of pine forest. Excavation continued to a depth of 90cm in one colony. These four colonies yielded 151±109 workers (mean number ±SD) and 69±38 cocoons (range 47-101). Only one worker had gemmae in each colony, and dissections confirmed that this was the gamergate (i.e. mated and egg-laying). All workers dissected had 16-20 ovarioles, and this number is diagnostic among closely related species (e.g. another species with large workers from Thailand has 8 ovarioles).

Distribution based on Regional Taxon Lists
Oriental Region: Bangladesh, India.

Biology
Different immature stages and adults of the wasp Schizaspidia diacammae (Chalcidoidea: Eucharitidae) were found inside several ant cocoons ([[Media:Peeters, C., Heraty, J. & Wiwatwitaya, D. 2015. Eucharitid wasp parasitoids in cocoons of the ponerine ant Diacamma scalpratum from Thailand.pdf|Peeters et al. 2015]]). Wasp larvae were feeding on ant pupae, while other host cocoons yielded five wasp pupae as well as both male and female adults. Parasitized cocoons are cut in a distinct manner by the wasps when they exit, and this feature can be used to assess the prevalence of parasitism. Dissection of the ovaries of one recently emerged physogastric wasp female revealed thousands of eggs ready to be laid. Among 9 families of wasps parasitic on ants, only Eucharitidae (56 genera) specialize in attacking the immature stages of ants.

Nomenclature

 *  scalpratum. Ponera scalprata Smith, F. 1858b: 84, pl. 6, figs. 21, 22 (w.) INDIA. Emery, 1889b: 496 (m.); Wheeler, G.C. & Wheeler, J. 1952c: 610 (l.). Combination in Diacamma: Mayr, 1862: 718. Senior synonym of compressum: Dalla Torre, 1893: 29; Emery, 1911d: 65. Current subspecies: nominal plus violaceum.
 * compressum. Diacamma compressum Mayr, 1879: 660 (w.) INDIA. Junior synonym of scalpratum: Dalla Torre, 1893: 29.

Ponera scalprata

Holotype worker in. Labelled “N. Ind. 54/16.” Acc. Reg.: “1854 no. 16. N. India (Sikkim, Him.) From Dr Hooker’s collection. Collected by Dr Hooker during his travels in n. India. A few of the insects were from Khasya Hills.”

A second scalprata specimen is in, but here the usual data label is missing and has been replaced by a white card square with, “Phil. N. India.” The half-written then deleted Phil (= Philippines) raises the possibility that this specimen may not be from the original type-series.