Myrmica pulchella

An endemic Taiwanese species.

Identification
A member of the ritae complex of the ritae species group. It has extremely coarse rugosity on the head dorsum (only four sinuous rugae between the frontal carinae level with the eyes), a feature shared with Myrmica margaritae, Myrmica sinensis and Myrmica emeryi. It well differs from M. margaritae by the presence of numerous standing hairs on the head margins and alitrunk dorsum and from M. emeryi - by the more abundant standing pilosity on the head margins ( > 20 long hairs vs. < 10). The absence of reticulation on the head dorsum distinguishes M. pulchella from both M. emeryi and M. sinensis. (Radchenko and Elmes 2010)

Distribution based on Regional Taxon Lists
Oriental Region: Taiwan.

Biology
Radchenko and Elmes (2010) - We found three nests on a bank by the side of a small road near Sun-moon lake, Chiayi Hsien, adjacent to a bamboo forest (quite large variety 4-5 m tall) at about 1600 m. The ants were found living in an intermodal cavity in semi-decayed pieces of cut bamboo (1-2 cm diameter), each contained> 100 workers and two contained a single queen. This was the first time we have seen any Myrmica species living in unstructured cavities in the field, although most species will happily colonise such spaces in laboratory conditions, provided the space can maintain a high relative humidity (at least 90%). Some North American species can live in hollow acorns, and in boreal conditions some species (e.g. Myrmica lobicornis) build small nests in rotten twigs, though in this case they usually hollow out the nest chambers themselves. We also observed a few foraging workers (mid morning) nearby that appeared to emerge from holes in the soil, but we could find no nest. Based on a sample of three nests one cannot say more than small colonies of this species adopt a cavity-living life-style. We have no way of knowing whether the colony size is typical for this species or whether they were relatively young colonies. Perhaps if they had grown larger they might have migrated to larger cavities in large pieces of bamboo. We did not search far into the bamboo forest because it was too dense to penetrate.

Castes
Males are unknown.

Nomenclature

 * formosae. Myrmica margaritae var. formosae Wheeler, W.M. 1929g: 37 (w.) TAIWAN. [Myrmica margaritae var. formosae Wheeler, W.M. 1928c: 9. Nomen nudum.] [Junior primary homonym of formosa Smith, F. 1858b: 128, above.] Subspecies of ritae: Weber, 1950b: 220. Raised to species: Radchenko, 1994a: 44. Senior synonym of pulchella: Radchenko & Elmes, 1998: 7; hence pulchella first available replacement name for this taxon: Radchenko & Elmes, 2010: 221.
 *  pulchella. Myrmica margaritae var. pulchella Santschi, 1937h: 368 (w.) TAIWAN. Radchenko & Elmes, 2010: 222 (q.). Junior synonym of formosae Wheeler, W.M. 1929g: 37 (junior primary homonym of formosa Smith, F. 1858b: 128): Radchenko & Elmes, 1998: 7; hence pulchella first available replacement name for formosae Wheeler, W.M.: Radchenko & Elmes, 2010: 221.

Worker
Wheeler (1929) for margaritae formosae - Length 4.5-6 mm.

Differing from the typical form of the species from Burma and the var. serica Wheeler from China in coloration. Head, thorax, pedicel and posterior 3/5 of the first gastric segment reddish piceous: pedicel somewhat darker; mandibles and antennae pale brown; checks, anterior portion of gula, legs and anterior 2/5 of gaster ivory yellow.

Queen
Radchenko and Elmes (2010) - they are distinctly larger than the workers and as in most Myrmica species there is some allometry in several body proportions. They have the same coarse sculpture of the body seen on the workers, the main difference is the shape of the propodeal spines that distinctly curve downwards (seen in profile) rather than straight.

Etymology
Radchenko and Elmes (2010) - from the Latin word pulchella = pretty, perhaps to describe the nice appearance of this species but more probably Santschi just translated “Formosa” to Latin.