Strumigenys hexamera (Brown, 1958) Brown, 1958

Tang, Kit Lam, Pierce, Mac P. & Guenard, Benoit, 2019, Review of the genus Strumigenys (Hymenoptera, Formicidae, Myrmicinae) in Hong Kong with the description of three new species and the addition of five native and four introduced species records, ZooKeys 831, pp. 1-48 : 15-17

Strumigenys hexamera (Brown, 1958) - new record Fig. 5 A–C

Epitritus hexamerus Brown 1958: 70, figs 1-3 (w.q.) JAPAN. Palearctic.

Pyramica hexamerus (Brown, 1958). Combination in Pyramica : Bolton 1999: 1672.

Strumigenys hexamera (Brown, 1958). Combination in Strumigenys : Baroni Urbani and De Andrade 2007: 122.

Material examined.

HONG KONG: Sha Tin District, Tai Po Kau, 22.42841N, 114.18197E, 22.02.2017, 160 m, R.H. Lee, Winkler, IBBL; Tai Po District, Ping Shan Chai, 22.486N, 114.187E, 25.03.2017, 142 m, C. Barthélémy, Malaise trap, IBBL.

Measurements.

Worker (n = 1): HL 0.47, HW 0.50, MandL 0.18, SL 0.22, EL 0.036, PW 0.27, ML 0.53, PL 0.23, PH 0.12, DPW 0.15, PPL 0.16, CI 106, MI 38, SI 44, OI 7, LPI 51, DPI 63. Queen (n = 1): TL 2.7, HL 0.54, HW 0.60, MandL 0.20, SL 0.25, EL 0.10, PW 0.37, ML 0.71, PL 0.34, PH 0.17, DPW 0.22, PPL 0.18, GL 0.78, CI 111, MI 37, SI 42, OI 17, LPI 48, DPI 65.

Geographic range.

Native: Japan (mainland and Ryukyu Islands), South Korea, Taiwan.

Introduced: Hong Kong, Ogasawara Islands (Japan), United States.

Ecology.

This is a rare species in Hong Kong with only two records, both from secondary forests at elevations of 142 and 160 m (Fig. 2). This species seems to have small monogynous colonies of about 35 individuals ( Terayama et al. 2014).

Comments.

The record of S. hexamera in Hong Kong represents the first record of this species for continental China. This species is known as an introduced species in Southeast USA (Alabama, Florida, Louisiana, and Mississippi), and was reported as introduced within the Ogasawara Islands ( Shindo 1979). Here we tentatively classify this species as introduced to Hong Kong in light of its tramp characteristics, including its known thelytokous reproductive strategy ( Masuko 2013), and the lack of previous collections in Hong Kong or other parts of mainland China. However, for this species, as for many tramp species across Asia, further study is needed to determine their exact origin and the extent of their native range.