Morphological study. We photographed the adults using a Sony DSC-RX100 v1.00 camera. To study the wing venation, the wings were removed from the thorax and cleaned with a 1:1 mixture of bleaching liquid. A Nikon D750 camera was used to photograph the venation. Abdomens were removed and macerated in hot 10% sodium hydroxide (NaOH) solution for examination of male genitalia, photographs of which were taken under a Keyence VHX-5000 digital microscope. Terminology of adult and genitalia follows Fang (2000).

Molecular phylogenetic analysis. We selected 19 samples representing the species of Olepa as the ingroup and, for the outgroup, we used Trischalis aureoplagiata and Cyclosiella spiralis (two species of the tribe Lithosiini of the subfamily Arctiinae). We sequenced four specimens from China and the remaining sequences were obtained from GenBank and Bold Systems. DNA was extracted from two or three legs of dried adult specimens using a TIANamp Genomic DNA Kit (Tiangen, Guangzhou, China) following the manufacturer’s instructions. We amplified a single mitochondrial gene (a 658-bp fragment of COI) using the general primers 1490-2198 (Folmer et al. 1994). The amplification protocol follows Hou et al. (2021). Sequences were aligned using Clustal W (Thompson 1997) and edited manually using MEGA 7.0 (Kumar et al. 2016). Maximum Likelihood analyses, shown in Fig. 4, were performed using IQ-tree v. 1.6.12 (Trifinopoulos et al. 2016) with the branch support values evaluated by 1000 ultrafast bootstrap (UFBS) replicates (Trifinopoulos et al. 2016) on the web server (http://iqtree.cibiv.univie.ac.at/), the best-fit model used being automatically selected by IQ-TREE (TIM2+F+I chosen according to Bayesian Information Criterion). New sequences have been deposited in GenBank (Table 1).

Figure 1.  

Adult of Olepa ricini (Fabricius, 1775) (♂).

Figure 2.  

Wing venation of Olepa ricini.

Figure 3.  

Male genitalia of Olepa ricini. A. lateral view of genitalia capsule; B. genitalia capsule flattened; C. phallus.

Figure 4.  

Maximum Likelihood (ML) tree for the species of Olepa, based on the COI gene. *OK576935 - OK576938 were collected in China.

The Chinese population of Olepa is morphologically similar to O. schleini and O. ricini. These two species were supposed to be distinguished from each other mainly by the differences in the tip of the valva, i.e. tip rounded in the former and more acute in the latter, together with a great genetic difference in COI sequences (Witt et al. 2005). In addition, another difference was also mentioned in the original description, that is the dark spots on forewing upper side are not surrounded by pale rings in the former, while the pale rings are usually present in the latter. However, based on our examined specimens, we found that the tip of the valva can be quite variable when viewed from different aspects and even flattened, hence we concluded this character cannot be regarded as a stable difference. Moreover, after conducting the BLAST procedure of the COI sequences of O. ricini (GenBank accession numbers AM050280-AM050284) used by Witt et al. (2005) in GenBank, we found that these sequences are actually closer to those of certain species in the family Geometridae rather than other members of Arctiinae of the family Erebidae. It is very likely that these COI sequences of O. ricini are wrong and are not the true ones of this species. This result can also explain why the genetic difference between O. ricini and O. toulgoeti was also as large as 18.2% to 18.5%, but the difference between O. schleini and O. toulgoeti was only 1.6% to 1.8%, despite the fact that O. schleini and O. ricini are morphologically closer. Based on our analysis, the genetic difference between Chinese Olepa sp. and Israeli O. schleini is 0%, the difference between two true Indian O. ricini (GenBank accession numbers KX371816 and KY559102) and Israeli O. schleini varies from 0.3% to 0.9% and the difference between Chinese Olepa sp. and Indian O. ricini also varies from 0.3% to 0.9%. Considering the fact that the genetic difference between the morphologically dissimilar O. ricini and O. toulgoeti is only 1.6% to 1.8% and the difference found between Indian O. ricini and Israeli O. schleini is smaller than 1%, we believe that all the three populations of O. ricini and O. schleini mentioned above should be regarded as conspecific. As for the difference in wing pattern, according to Orhant (1986), the lectotype of O. ricini housed in the Natural History Museum of Denmark is a female without abdomen (plate 1, figs. 4 and 5 in Orhant 1986) and the holotype of O. schleini is a male deposited in Museum Witt Munich, but the adult of this specimen was not specified in the plates in Witt et al. (2005). By comparing the female lectotype of O. ricini and illustrations of males of this species from various publications with males and females of O. schleini figured in Witt et al. (2005), we found no significant difference between these individuals and, interestingly, the pale rings are mostly reduced in the lectotype of O. ricini, similar to the situation in O. schleini. Hence, we concluded that this character is most probably due to individual variation. Thus, we herein present the following synonym: Olepa schleini Witt et al., 2005 syn. n. = Olepa ricini (Fabricius, 1775) and the Chinese Olepa sp. should be also identified as O. ricini.