3.5 AT-rich Region
The AT-rich region is the longest non-coding region with a relatively high AT content, deemed to be related to the origin of replication and transcription (Boore, 1999; Cameron, 2014), and usually located betweenrrnS and trnM . In this study, this region ranges from 89.3% to 91.9%, with the longest (A.virgata ) being 379 bp the second longest (Halpe nephele ) being 374 bp, and the shortest (O.maga ) being 369 bp in size (Table 3). In this study, a poly-T and poly-A stretches are all present with varying lengths in the AT-rich region. The poly-T length ranges from 16 bp to 22 bp, and the poly-A stretch ranges from 12 bp to 24 bp, often interrupted by the base T (Figure 4). These 2 types of T/A tandem repeats in the AT-rich region have been reported in other determined Hesperiidae mitogenomes (Han, Huang, Tang, Chiba, & Fan, 2018).