Strumigenys minutula

Nests are found under stones or in the soil of grassland or sugarcane fields in Japan (Japanese Ant Image Database). In Hong Kong, Tang et al. (2019) found this to be a rather uncommon species collected from tree plantation, secondary forest, and Feng Shui woods. The known elevation range of this species in Hong Kong is from 29 to 475 m. A colony including three dealate queens, 47 workers, 97 pupae, and 80 larvae was collected in a log at Tai Po Kau on May 18, 2016. The presence of multiple queens and the high number of pupae and larvae retrieved indicate that functional polygyny and large colony size (300 individuals) as previously reported occur within this species (Terayama et al. 2014). A single alate gyne was collected between June 26 and July 10 in a Malaise trap located within a mangrove area.

In contrast to Hong Kong, where this species has been rarely collected (Tang et al. 2019), S. minutula was frequently found in Macao since its first collection in 2017 (Leong et al. 2017). Individuals were commonly found within leaf litter samples, and a full colony was also retrieved within one of the ground nests deployed (see Fig. 11). At the time of collection on (29 August 2019), the colony consisted of 135 workers, two dealate queens, eight larvae, and 12 pupae (eggs were not counted). This represents a similar colony size as described previously from Japan, where a polygynous colony of 300 individuals was recorded (Terayama et al. 2014). Note that, on the left foreleg of the queen imaged (Fig. 10E), a mite is attached. It remains to be investigated which mite species it is, and if this represent a case of parasitism, phoresis or myrmecophily in S. minutula.

In contrast to Hong Kong, where this species has been rarely collected (Tang et al. 2019), S. minutula was frequently found in Macao since its first collection in 2017 (Leong et al. 2017). Individuals were commonly found within leaf litter samples, and a full colony was also retrieved within one of the ground nests deployed. At the time of collection on (29 August 2019), the colony consisted of 135 workers, two dealate queens, eight larvae, and 12 pupae (eggs were not counted). This represents a similar colony size as described previously from Japan, where a polygynous colony of 300 individuals was recorded (Terayama et al. 2014). Note that, on the left foreleg of the queen imaged, a mite is attached. It remains to be investigated which mite species it is, and if this represent a case of parasitism, phoresis or myrmecophily in S. minutula. (Brassard et al., 2020)

Identification
Bolton (2000) - A member of the godeffroyi complex in the Strumigenys godeffroyi-group. See notes under Strumigenys nanzanensis.

Distribution based on Regional Taxon Lists
Oriental Region: Taiwan. Palaearctic Region: China, Japan.

Biology
Chien and Lin (2015) analyzed the chemical constituents of the venom of five Taiwanese Strumigenys species: Strumigenys chuchihensis, Strumigenys formosensis, Strumigenys liukueiensis, Strumigenys minutula and Strumigenys solifontis for a chemotaxonomy study. The venom was collected from extruded stings and was thought likely to contain a mixture of poison (venom) and Dufour gland secretions. GC/MS profiles showed that three of the five species were clearly differentiated by the chemical composition of their sting secretions. Two remaining two species, S. chuchihensis and S. liukueiensis, showed chemical signatures that were not significantly different from one another.

Nomenclature

 *  minutula. Strumigenys minutula Terayama & Kubota, 1989: 782, figs. 13-17 (w.q.) TAIWAN. See also: Bolton, 2000: 795.

Worker
Bolton (2000) - TL 2.0, HL 0.52-0.54, HW 0.37-0.30, CI 69-74, ML 0.18-0.20, MI 35-38, SL 0.28-0.30, SI 74-77, PW 0.22-0.23, AL 0.54-0.56 (4 measured). Characters of godeffroyi-complex. Cephalic dorsum with pair of erect hairs closest to midline on occipital margin fine, basal portion of hair erect and apical third or more abruptly angled or hooked anteriorly, or looped. With head in full-face view the dorsolateral margin posterior to the flagellate apicoscrobal hair without 3-4 stiffly projecting hairs; either without such hairs at all or at most with a single stiff hair immediately posterior to the flagellate hair. When a single such hair occurs it contrasts strongly with the marginal hairs anterior to the flagellate hair, being more cylindrical (i.e. not spatulate), more elevated and less strongly curved anteriorly. Ground-pilosity on pronotal dorsum short and sparse, not forming a dense pelt. Dorsum of pronotum reticulate-punctate and with a pair of erect flagellate hairs in addition to the humeral pair. Pleurae and side of propodeum mostly to entirely smooth, any reticulate-punctate sculpture present is confined to periphery. Propodeal declivity with a broad and very conspicuous spongiform lamella, the propodeal teeth only weakly expressed (may be vestigial) and entirely buried in the lamella. Dorsal surface of propodeal tooth in profile surmounted by a convex crest or ridge of spongiform tissue. In dorsal view petiole node un sculptured; lateral margins of node converge anteriorly and terminate in an anteromedian blunt point so that shape of dorsum of node is roughly triangular; lateral spongiform lobes extend anteriorly to, or almost to, the apex of the anteromedian point. Disc of postpetiole unsculptured. Basigastral costulae conspicuous but not extending half the length of the tergite.

Type Material
Bolton (2000) - Holotype worker, paratype workers and queen, TAIWAN: Nantou Hsien, Puli, 4.viii.1981 (Terayama & Kubota); paratype workers and queens, TAIWAN: Nantou Hsien, Puli, 20.viii.1987 (H. Sakai); JAPAN: Okinawa-bonto I., Naba City, 13.ix.1981 (M. Terayama); Uenobara, 12.vi.1984 (H. Takamine); Nandai, 23.vi.1985 (H. Takamine); Hisadaka, 24.vi.1985 (H. Takamine); Okinawa Pref., Iriomote-jima I., 13.viii.1979 (M. Terayama); Kagosbima Pref., Tokunosbima I., 29.vii.1985 (M. Terayama) [not seen].

References based on Global Ant Biodiversity Informatics

 * Bolton, B. 2000. The Ant Tribe Dacetini. Memoirs of the American Entomological Institute 65
 * Hu C.-H. 2006. Indigenized conservation and biodiversity maintenance on Orchid Island. PhD Thesis, graduate school of the University of Minnesota. 150 pages.
 * Leong C. M., S. F. Shiao, and B. Guenard. 2017. Ants in the city, a preliminary checklist of Formicidae (Hymenoptera) in Macau, one of the most heavily urbanized regions of the world. Asian Myrmecology 9: e009014.
 * Li Z.h. 2006. List of Chinese Insects. Volume 4. Sun Yat-sen University Press
 * Lin C.C., and W.J. Wu. 1996. Revision of the ant genus Strumigenys Fr. Smith (Hymenoptera: Formicidae) of Taiwan. Chinese Journal of Entomology 16:137-152.
 * Tang K.L., Pierce M.P., and B. Guénard. 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: 1-48.
 * Terayama M. 2009. A synopsis of the family Formicidae of Taiwan (Insecta: Hymenoptera). Research Bulletin of Kanto Gakuen University. Liberal Arts 17:81-266.
 * Terayama M., S. Kubota, and K. Eguchi. 2014. Encyclopedia of Japanese ants. Asakura Shoten: Tokyo, 278 pp.
 * Terayama M., and S. Kubota. 1989. The ant tribe Dacetini (Hymenoptera, Formicidae) of Taiwan, with descriptions of three new species. Japanese Journal of Entomology 57: 778-792.
 * Terayama Mamoru. 2009. A synopsis of the family Formicidae of Taiwan (Insecta, Hymenoptera). The Research Bulletin of Kanto Gakuen University 17: 81-266.
 * Terayama, M. 2009. A synopsis of the family Formicidae of Taiwan (Insecta; Hymenoptera). The Research Bulletin of Kanto Gakuen University 17: 81-266.
 * Terayama. M. and Inoue. N. 1988. Ants collected by the members of the Soil Zoological Expedition to Taiwan. ARI Reports of the Myrmecologists Society (Japan) 18: 25-28
 * Yamane S. 2016. How many species of Ants in Amami Islands? (in Japanese). Part 2, chapter 1 in How many species of Ants in Amami Islands? Pp. 92-132.
 * Yamane S., S. Ikudome, and M. Terayama. 1999. Identification guide to the Aculeata of the Nansei Islands, Japan. Sapporo: Hokkaido University Press, xii + 831 pp. pp, 138-317.
 * Yamane S.; Ikudome, S.; Terayama, M. 1999. Identification guide to the Aculeata of the Nansei Islands, Japan. Sapporo: Hokkaido University Press, xii + 831 pp. pp138-317.