Pedesta rubella ( Devyatkin, 1996 )

Li, Meng, Monastyrkii, Alexander L., Kolesnichenko, Kirill A., Liu, Zihao, Xue, Guoxi, Long, Jifeng & Tang, Huaxing, 2020, Morphological and molecular characters reveal the status of Pedesta rubella (Devyatkin, 1996) stat. n. and P. similissima (Devyatkin, 2002) syn. n. (Lepidoptera, Hesperiidae), Zootaxa 4743 (2), pp. 217-231 : 221-223

Pedesta rubella ( Devyatkin, 1996) stat. n.

( Fig. 2, Figs. 3–8)

Thoressa submacula rubella Devyatkin, 1996: 603 , type locality: near Moc-Chau, northern Vietnam; Monastyrskii & Devyatkin 2015: 77.

Thoressa submacula: Devyatkin 2002: 128 , fig. 2 (misidentification); Ikeda et al. 2001: 64, fig. 21 (misidentification).

Diagnosis. Based upon specimens examined and field investigation, the wing pattern variability of Pedesta rubella is recognized as follows: on the forewing, subapical spots in spaces R 4 –R 5 may be wide and strip shaped ( Fig. 3, Fig. 25b), or narrow and dot like ( Figs. 4–7, Fig. 25a); on the dorsal side, the dot in space R 3 may be prominent ( Figs. 3, 7) or nearly vanish ( Figs. 4–6); the lower cell spot is sometimes elongated toward wing base ( Figs. 4, 5), or equally sized with the upper one ( Figs. 3, 7), or even smaller ( Fig. 6); spots in spaces M 3 and CuA 1 are wide ( Fig. 3) or relatively narrower ( Fig. 5). On the ventral side of the hindwing, two basal spots in space Sc+R 1 are well separated ( Figs. 4, 6, 7, Fig. 25a) or connected ( Figs. 3, 5, Fig. 25b); between the basal and submarginal spots in spaces M 1 –M 2 there is sometimes a pair of white spots which form the postdiscal series with those in spaces Rs, M 3 and CuA 1 ( Figs. 6, 7, Fig. 25b). This variability can be observed among individuals of the same group ( Fig. 25), and does not represent seasonal forms. Wing patterns of P. submacula fall into this variability ( Figs. 9–17), so the two species can hardly be distinguished without an examination of genitalia.

The differences in male genitalia of Pedesta submacula ( Fig. 18) and P. rubella ( Fig. 19, Fig. 20) are as below:

1. In dorsal view, the uncus of Pedesta submacula is obviously wider (it is narrower in P. rubella ), and the two distal branches are pointed (they are slender and blunt pointed in P. rubella ), between which there is a Ushaped gap (the gap is narrower or V-shaped in P. rubella ).

2. In Pedesta submacula , there is usually a pair of short triangular horns on the dorsal side of the tegumen terminally, and sometimes the horns are rather long and sharply pointed ( Fig. 26, Fig. 27). But in P. rubella they are vestigial or absent.

3. In lateral view, the distal branches of both valva are robust and semi-erect in Pedesta submacula , but they are usually slender, longer, and erect in P. rubella .

Among the specimens of Pedesta rubella , distal branches of valva in some individuals are robust ( Fig. 21).

Nevertheless, the shape of the uncus is always a good character to distinguish the two species.

Note. The holotype of Pedesta submacula is not examined in this study, but the possibility that it belongs to P. rubella can be excluded due to the great distance between the type locality of P. submacula , viz. Changyang (Hubei Province, China) and the range of P. rubella ( Fig. 28).

Although Pedesta rubella is proved to be a separate species, the unique wing pattern and the remarkable bifurcate distal branch of the right valva of the holotype are conspicuously different from those of the specimens from other localities. If more materials bearing the same morphological characters as the holotype can be found in the future, it will be possible to consider the population from other localities as a distinguishable subspecies of P. rubella . But for now, it is more reasonable to treat the holotype as an individual variation of the species.

Description. Females of Pedesta rubella ( Fig. 8) and P. submacula ( Figs. 11, 13, 15, 17) exhibit similar wing patterns. Unlike the corresponding males, in the lower half of space CuA 2 there is a small triangular patch located near vein 2A, and the line connecting the patch and cell spots is perpendicular to the costa. Genitalia are described as follows to distinguish the females of the two species.

Female genitalia of Pedesta rubella ( Fig. 22). Papillae anales flabellate in lateral view, covered with long hairs. Apophyses posteriores three times as long as papillae anales. Lamella postvaginalis and lamella antevaginalis well developed and sclerotized. In ventral view, middle of posterior edge of lamella postvaginalis extended to be a fishtail plate, of which basal half tapered and distal margin shallowly concave. Lamella antevaginalis almost triangular, each side of basal area bear an elongated plate with irregular distal margin; middle of posterior edge protruding, round. Ductus bursae tube-like; bursa copulatrix bursiform, constricted in middle, without signum.

Female genitalia of Pedesta submacula ( Fig. 23). Similar to P. rubella , but extended plate of lamella postvaginalis more developed, shovel-shaped; lamella antevaginalis triangular, top angle blunt, base angle on each side much smaller and sharply pointed.

Bionomics. Most specimens of GX-group were caught in limestone karst habitat in Nonggang NNR ( Fig. 24). In this subtropical area, Pedesta rubella is common from April to October. The adults fly rapidly and prefer to suck mud or liquid on the ground ( Fig. 25). The males also like to occupy the crown of shrubs as a territory and drive out intrusive butterflies. According to our investigations, females of this species appear to be remarkably less numerous than males.