Review of ants from the genus Polyrhachis Smith (Hymenoptera: Formicidae: Formicinae) in Hong Kong and Macau, with notes on their natural history

Abstract

Polyrhachis is one of the most taxonomically and ecologically diverse ant genera in the world. Limited knowledge is, however, available on the species encountered within continental South East Asia, contrasting with the extensive studies conducted on African and Indo-Australian species. Here a contribution of Polyrhachis species from Hong Kong and Macau based on specimens collected in the past 30 years, with addition of material from other southeast Chinese provinces is provided. Additionally, new nest collections of P. dives Smith allowed a better understanding of its natural history and nest composition. A total of 17 Polyrhachis species were identified within Hong Kong and Macau, completed by the descriptions or redescriptions of their worker, males and queen castes, including the novel description of the queen caste of P. demangei Santschi. Four new species are discovered and seven species are newly recorded in the regions studied: P. confusa sp. nov., P. fellowesi sp. nov., P. hunggeuk sp. nov., P. moesta Emery, 1887, P. peetersi sp. nov., P. punctillata Roger, 1863, P. rastellata Latreille, 1802, and P. rufipes Smith, 1858, in Hong Kong; P. latona Wheeler, 1909, P. confusa sp. nov. and P. tyrannica Smith, 1858, in Macau; P. demangei in Zhejiang, P. rufipes in Hainan and P. fellowesi sp. nov. in Guangdong, Guangxi and Zhejiang. A dichotomous key based on the worker caste for the 17 species encountered in Hong Kong and Macau is provided, as well as additional data about their distribution and natural history. Altogether these results highlight the lack of ecological and distribution knowledge on this conspicuous genus of ants and the need for future fieldwork in southeast China.