A Checklist of Ants (Hymenoptera: Formicidae) of Hainan Province, China

Hainan Province is a tropical island identified as a global biodiversity hotspot, but limited sampling and taxonomic efforts have been conducted to catalog and describe its ant fauna. Here, we compiled valid historical records and new records based on past and recent ant surveys, to present the first checklist of ants specific to Hainan. In total, we identified 10 subfamilies, 67 genera, and 237 species, a 60% increase in the previous species checklist. A total 25 genera and 89 nominal species are newly recorded for the island, and 109 morphospecies are detected. The checklist also includes 15 exotic species, among which Pheidole megacephala (Fabricius, 1793) and Solenopsis invicta Buren, 1972 can be considered as invasive. Despite this update, we provide several lines of evidence to argue that the Hainan ant fauna remains largely understudied. Together, these findings not only highlight the rich biodiversity present but also the importance of increasing the species cataloguing rate and taxonomic work for the island. The use of additional sampling approaches, and new surveys targeting a wider geographic and ecological span might represent an efficient approach to fill this knowledge gap.