Prenolepis subopaca

Peeters and Yong (2017) discovered Prenolepis subopaca nesting in the leaf litter and foraging arboreally (see linked video and further details in the biology section below). Heterick & Kitching (2022) collected this species in a ground malaise trap within a lowland dipterocarp forest in Brunei.

Identification
Williams and LaPolla (2016) - Gracile with elongate legs (HTI > 185), antennae (SI > 185), and mesosoma (BLI > 175); in profile view, the mesosoma is especially slender and has a distinct shape, with the propodeum much taller than the pronotum (Fig 27); no erect macrosetae on the propodeum; petiole is narrow and elongate (PetWI < 55); dorsal surface of pronotum, propodeum, and gaster covered in fine, dense pubescence; scale of petiole is rounded at its apex.

This species is most similar to Prenolepis jerdoni, but can be distinguished by its finely reticulate and dull cuticle and thick patches of pubescence on the dorsal surface of the pronotum, propodeum, and gaster. Prenolepis subopaca has very large compound eyes that are similar to those of Prenolepis naoroji, but P. naoroji has a distinct light blue cuticular iridescence and a shorter petiole than P. subopaca.

Distribution based on Regional Taxon Lists
Indo-Australian Region: Brunei Darussalam, Indonesia, Malaysia, Singapore.

Biology
Very little is known about foraging habits and life history. Just after dusk, Peeters & Yong (2017) observed a large and fairly compact group of P. subopaca walking down a tree (video ), before vanishing in leaf litter on the ground. Swollen gasters indicated that they were retrieving honeydew to their nest. A second colony was found under layers of leaf litter, about 5 to 10 cm deep. An estimated 300 workers were present with numerous brood, one winged queen and one male. After disturbance, the ants scattered and ran deeper into the leaf litter carrying their brood (pupae, larvae and eggs). After some time, clear trails were formed and ants travelled along these. A worker carried an isopod along the trail. Ants in this colony lacked enlarged gasters.

Nomenclature

 *  subopaca. Prenolepis jerdoni var. subopaca Emery, 1900d: 699 (w.) INDONESIA (Sumatra).
 * Status as species: Williams & LaPolla, 2016: 242.

Worker
Williams and LaPolla (2016) - (n=17): CMC: 7–18; EL: 0.24–0.31; EW: 0.18–0.26; HL: 0.71–0.98; HLA: 0.38–0.50; HLP: 0.25–0.33; HW: 0.58–0.85; IOD: 0.42–0.53; LF1: 0.21–0.28; LF2: 0.15–0.20; LHT: 1.17–1.80; MMC: 0–1; MTW: 0.40–0.51; MW: 0.24–0.38; PDH: 0.29–0.43; PMC: 2–4; PrCL: 0.50–0.69; PrCW: 0.24–0.35; PrFL: 0.92–1.35; PrFW: 0.18–0.25; PTH: 0.29–0.43; PTL: 0.44–0.56; PTW: 0.21–0.30; PW: 0.48–0.60; SL: 1.23– 1.67; TL: 2.74–4.29; WF1: 0.06–0.09; WF2: 0.06–0.08; WL: 1.04–1.59; BLI: 176–206; CI: 80–87; EPI: 150–160; FLI: 135–146; HTI: 202–222; PetHI: 95–102; PetWI: 49–53; PrCI: 48–53; PrFI: 17–21; REL: 30–34; REL2: 35–41; REL3: 54–62; SI: 188–214.

Medium to dark brown; entire cuticle finely reticulate and dull; abundant decumbent setae on scapes and legs; very long, erect macrosetae on head, mesosoma, and gaster; no erect macrosetae on propodeum; fine and dense pubescence covering the dorsal surface of the pronotum, propodeum, and gaster; head slightly longer than broad and oval in shape with indistinct posterolateral corners and a convex posterior margin; eyes large and strongly convex, surpassing the lateral margins of the head in full-face view; torulae do not touch the posterior border of the clypeus; clypeus strongly medially convex and without prominent anterolateral lobes; mandibles with 5–7 teeth (usually 6) on the masticatory margin; ectal surface of mandibles smooth and shiny; metatibia relatively elongate (HTI > 185); in profile view, propodeum is much taller than pronotum and domed with a rounded dorsal face; petiole is narrow and elongate (PetWI < 55) with a rounded dorsal apex of the scale.

Type Material
Holotype worker, Indonesia: Sumatra, Si-Rambé, 01.xii.1890 (E. Modigliani) (: CASENT0905792) [examined].