Cataulacus muticus

Cataulacus muticus live in hollow internodes of plants and exhibit two interesting behaviors that help them ward off occasional flooding threats. When heavy rains produce conditions where water can infiltrate their nests, workers will use their phragmotic heads to block their nest entrances and stem water flowing into their nest chambers. A second behavior, and one that is so far unique within ants, is to practice what has been coined communal peeing. Many workers imbibe water within the nest, leave the nest, excrete water droplets and deposit these on the outer stem of the plant. (Maschwitz and Moog 2000 and Moog 2005)

Identification
A member of the granulatus group. A medium-sized species, definitely of the granulatus-group and seemingly closely related to Cataulacus granulatus itself, and yet distinguished by the presence of blunt propodeal tubercles instead of spines, the node of the petiole which is distinctly longer than broad, and the relatively smooth sides of the propodeum. The head, alitrunk and pedicel are relatively coarsely sculptured.

Regional Cataulacus Key

Distribution based on Regional Taxon Lists
Indo-Australian Region: Malaysia. Oriental Region: India, Myanmar.

Biology
In west Malaysia this species lives inside the internodes of two plants, Gigantochloa scortechinii and Dendrocalamus asper. They form large monogynous, polydomous colonies that can contain more than 2,000 workers and spread to the internodes of several neighboring culms. (Maschwitz and Moog 2000)

Genetics
Polymorphic microsatellites have been identified for this species. (Debout et al. 2002)

Nomenclature

 *  muticus. Cataulacus muticus Emery, 1889b: 507, pl. 10, fig. 17 (w.) MYANMAR.

Worker
Bolton (1974) - TL 5.5 - ca 6.0. Head as in granulatus but proportionately larger and with the denticles of the sides of the head behind the eyes larger and more produced. Sides of pronotum and mesonotum strongly denticulate, but the sides of the propodeum with only one or two denticles and converging posteriorly. Propodeum with a pair of obtuse and blunt tubercles (referred to in Bingham as 'slightly produced rounded projecting laminae'). Petiole distinctly longer than broad, rather slender; postpetiole longitudinally oval, truncated in front and behind. Gaster as in granulatus. Head, alitrunk and pedicel very coarsely reticulate-rugose, the pedicel remarkably rugose. Gaster finely punctate and with fine longitudinal rugulae. Pilosity 'rather long', whitish in colour.

Type Material
Bolton (1974) - Holotype worker, BURMA: Tenasserim, Thagata, Mt. Mooleyit (L. Pea) (probably in MCSN, Genoa).