ASIAN MYRMECOLOGY Volume 9, e009014, 2017 ISSN 1985-1944 | eISSN: 2462-2362 © Chi-Man Leong, Shiuh-Feng Shiao DOI: 10.20362/am.009014 and Benoit Guénard Ants in the city, a preliminary checklist of Formicidae (Hymenoptera) in Macau, one of the most heavily urbanized regions of the world Chi-Man Leong1, Shiuh-Feng Shiao1 and Benoit Guénard2* 1National Taiwan University, Department of Entomology, No.1, Sec.4, Roosevelt Road, Taipei, Taiwan 2University of Hong Kong, School of Biological Sciences, Kadoorie Biological Sciences Building, Pok Fu Lam Road, Hong Kong SAR, China *Corresponding author: [email protected] ABSTRACT. Macau is a small territory in South East China and one of the most densely populated regions in the world. Previous studies on insect groups have shown that a relatively diverse, yet specific, fauna could still survive in this region. However, to this point, studies on the myrmecofauna of Macau are scarce and to date no species checklist exists. Here, we present the first checklist of Macanese ant species by combining results from recent ant surveys using hand- collections and Winkler extractors with published records. During the surveys, 82 species and morphospecies belonging to 37 genera and 8 subfamilies have been collected, with 37 species representing new records for Macau, including an interesting new record of an undescribed Leptanilla species, the second record of the Leptanillinae subfamily for South East China. To date, Macanese ants comprise 105 species/morphospecies and 8 subspecies, after the removal of dubious records present in the literature (though some misidentifications may remain). While still likely incomplete, these results represent the most comprehensive list of ants for Macau, and a baseline for future research on ant diversity in heavily urbanized environments and for understanding the potential consequences of urbanization on native and non-native diversity in Asia. Keywords: Ants, Checklist, Exotic Species, Macao, Diversity Survey, Urban Ecosystems. INTRODUCTION Located in the subtropical part of China, Macau Special Administrative Region (SAR) Globally, urban development has been constantly (22.2˚N, 113.5˚E) lies on the south west side of expanding; in one analysis, by 2050, 70% of the the Pearl River mouth, and is a small territory of global human population is expected to live with- 30.4 km2, encircled within the Chinese province in cities leading to an increase of urbanized areas of Guangdong. Similar to several cities in South (Seto et al. 2013). In this context, understanding China, Macau has experienced rapid urban de- what role urban habitats can play to maintain a velopment over the past decades and as of 2017 certain level of biodiversity and which species its population density is the highest in the world are present in these environments is key to future with 20,166 inhabitants per km2: 2.5 and 3 times ecology and conservation. higher than Singapore and Hong Kong respec- 2 Chi-Man Leong, Shiuh-Feng Shiao & Benoit Guénard tively (Information Services Department Hong of Macau was provided in the 1920’s in a series Kong Special Administrative Region Govern- of articles by the American myrmecologist Wil- ment 2015; United Nations 2015; Statistics and liam Morton Wheeler, and embedded with other Census Service 2017). Historically, Macau con- records for various parts of China (Wheeler 1921, sisted of a peninsula connected to Guangdong, 1928, 1930). A few other records from Macau and of two islands: Coloane Island (8.07 km2) and were reported or cited in various taxonomic revi- Taipa Island (7.6 km2). Over the past decades, im- sions on Chinese or Asian ants (Xu 2003; Eguchi portant land reclamation over the ocean has led to 2008). Over the past two decades, several records the merging of Coloane and Taipa Islands togeth- of Macau ants were included within Chinese er. Despite this important urbanization and land species checklists, yet with no or little specific changes, a few “natural” areas and parks have sampling efforts for this territory (e.g. Wu 1941; been preserved. For example, Ka Ho and Hac Chapman & Capco 1951; Tang et al. 1995; Zhou Sa Reservoirs on Coloane Island are freshwater- 2001; Fellowes 2006; Hua 2006; Guénard & wetland ecological zones, and areas of these two Dunn 2012; Ran & Zhou 2011, 2012, 2013); and reservoirs are regulated for the conservation pur- existing records of Macanese ants were not in- pose of an endemic moss Fissidens macaoensis cluded in a checklist of ants in Guangdong (Zhao (Zhang & Hong 2011) and an endemic mosquito et al. 2009). Despite these limited efforts and the Toxorhynchites macaensis (Ribeiro 1997). small area that Macau represents, two species and Regarding the Macanese insect fauna, subspecies of ants have been described on the ba- several groups like butterflies and moths (Lepi- sis of specimens collected there, namely Care- doptera) (Easton & Pun 1997a, b), water beetles bara capreola laeviceps (Wheeler, 1928) and (Coleoptera) (Jäch & Easton 1998), stink bugs Crematogaster macaoensis Wu & Wang 1995, (Homoptera) (Easton & Pun 1999), mosquitoes, with this latter recorded from other Chinese prov- sandflies, and blackflies (Diptera) (Ou 2001) or inces as well (Guénard & Dunn 2012; antmaps. again damselflies (Zygoptera) (Wilson & Xu org 2017). The subspecies C. capreola laeviceps 2007) have been previously surveyed in Macau, is endemic to Macau, however as no recent work but other major taxonomic groups that com- has examined the taxonomic validity of this spe- pose the Macanese biodiversity are still poorly cies, the possibility that this species represents known, including ants (Formicidae). Yet, under- a synonym should not be excluded. In addition, standing ant diversity and species composition is most historical records were reported without important. For instance, within an urban matrix specific collecting locations in Macau and with- composed of a diversity of habitats, even small out habitat information, which limits the under- natural patches of natural habitats can still sup- standing of the distribution of these species. As port high species diversity of ants (Menke et al. a result, knowledge on Macanese ants is at this 2011; Guénard et al. 2015), while on the other point limited, and in order to establish a landmark hand non-native or habitat disturbance specialist allowing improved future work on ant diversity species can represent a significant portion of the and conservation on this territory, a first species myrmecofauna within the habitats (Guénard et checklist is currently needed. al. 2015). Moreover, as ants represent a dominant Here, we present the results of a pre- group among arthropods and show sensitivity to liminary ant survey conducted in the main natu- environmental changes in relation to disturbance, ral habitats of Macau. We then establish the first they can represent a good bioindicator across dif- comprehensive species checklist of Macanese ferent habitats and help in monitoring their re- ants based on newly collected materials and spective ecological values (Andersen et al. 2002; published records. This checklist may benefit Del Toro et al. 2012). knowledge of the ants from Macau and South- To the best of our knowledge, no spe- East China, and provide detailed information for cific checklist or sampling has been realized to future studies. In addition, the discussion on ant characterize ant diversity in Macau, and only community of each study site is also presented sporadic records have been reported in the litera- to provide insights on the effects of urbanization ture. To date, the most comprehensive list of ants on ants. Ants in the city, a preliminary checklist of Formicidae (Hymenoptera) in Macau 3 Fig. 1. Map of Macau SAR presenting the sampling locations (modified after Google Map 2017). Pie charts rep- resent the ant composition in native (white), tramp (grey) and exotic species (black) for the sites with the most complete sampling effort. MATERIALS AND METHODS them we surveyed for about five hours using hand collection; in 2016 and 2017, a total of fourteen The main sampling sites were located on Guia field sessions were realized, again for about five Hill on the Macau Peninsula, Tai Tam Hill and hours using hand collection but coupled with the Siu Tam Hill on Taipa Island and Ka Ho and Hac use of a Winkler extractor, this latter being an ef- Sa Reservoirs on Coloane Island (sampling loca- ficient method to collect cryptobiotic ants pres- tions shown on Figure 1). Field work was con- ent in the leaf litter as well as ground dwelling ducted from July to August 2015, July to August ants (Bestelmeyer et al. 2000). In addition, some 2016, January 2017 and July to August 2017. It specimens collected in diverse locations of Ma- should be noted that sampling effort among the cau were generously provided by Mr Martinho G. different sites was not standardized and more Oxalá and Mr Chi-Yui Lei. effort was applied on sites located on Coloane For hand collection, we searched for Island, to deliberately target more natural and ants visually with a specific focus on the ground, mature habitats preserved on this island rather under rocks, in rotten wood (breaking it open), than the urbanized and isolated habitats present and on tree trunks with the help of an insect aspi- on Taipa Island and Macau Peninsula. In 2015, a rator. For Winkler extractor sampling, six litres of total of 23 field sessions were realized; in each of sifted leaf litter (abundantly decomposed organic 4 Chi-Man Leong, Shiuh-Feng Shiao & Benoit Guénard materials) were collected within each site and examining these records. Thus, to identify poten- chosen to maximize the number of micro-habitats tial dubious records, we used information on spe- sampled and thus ant diversity (Ward 2000). Leaf cies’ known distributions available on antmaps. litter was dried in a Winkler extractor for seven org (Janicki et al. 2016; Guénard et al.