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

Abstract. The species of the ant genus Strumigenys Smith, 1860 found in Hong Kong are reviewed based on new sampling efforts performed over the past five years (2014–2018). Prior to this, 12 Strumigenys species had been recorded from Hong Kong, all confirmed here. Moreover, we add to this list three newly described species: S.hirsutasp. n., S.lantauisp. n., and S.nathistorisocsp. n., and describe for the first time the worker caste of S.formosa Terayama, Lin & Wu, 1995. We report new records for nine additional species, bringing the total number of species to 24, including four newly recorded species (S.hexamera Brown, 1958, S.membranifera Emery, 1869, S.nepalensis Baroni Urbani and De Andrade, 1994, and S.rogeri Emery, 1890) which are considered to be introduced to Hong Kong. A global review of the introduced Strumigenys species is presented. The taxonomic validity of S.feae and S.formosensis is discussed in light of new specimen measurements. New ecological information on the swarming periods of 11 species is presented on the basis of year-long sampling of aerial insects. Finally, the importance of our results within Southeast Asia and the need for future sampling efforts in the region is discussed.