DNA Barcoding Applications in Ants (Hymenoptera: Formicidae)

Taxonomy is fundamental to all organismic research. Therefore, the integration of molecular and morphological data is increasingly encouraged for more accurate species identification. However, the emphasis on and application of DNA barcoding methods appear to vary across different taxonomic groups. Ants, among the most prominent invertebrate groups, seem to have their taxonomic research primarily focused on morphological characteristics, with studies incorporating molecular species identification remaining relatively underrepresented. Thus, understanding the application profile of DNA barcoding in ants can provide guidance for future taxonomic research. By downloading and analyzing 350,686 sequences of eight gene fragments from the NCBI and BOLD databases, it was found that COI remains the most prevalent molecular marker, yet sequences vary in length. Only 190,880 sequences (67%) meet or exceed the standard length (658 bp), covering 15 subfamilies, 273 genera, and 3226 species (<23.00%). Among COI sequences, 32,444 sequences (9.60%) are unidentified species, spanning 12 subfamilies and 175 genera; sequences from Europe and America dominate (60%), while those from China are exceptionally scarce (0.35%). DNA barcoding analysis of representative sequences revealed inconsistencies with annotated species for some entries. These findings demonstrate that molecular data for ants are extremely limited, and existing data exhibit significant spatial and taxonomic biases. Moving forward, enhancing systematic taxonomic studies of Chinese ants—particularly accumulating DNA barcoding databases—is essential to uncover greater ant diversity, monitor invasive species, and inform conservation strategies.