Seeing Through the Mimicry of Papilio bootes by Combining Computer-Aided and Human Eyesight Morphological Comparisons

The Tailed Redbreast Papilio bootes exhibits a tendency for specific mimicry of sympatric Byasa species across its distribution range, but this phenomenon has not yet been quantitatively analysed. To address this intriguing example of Batesian mimicry, the present study focused on three provinces (Yunnan, Sichuan, and Shaanxi) in West China, which have high taxonomic diversity of both P. bootes and Byasa. We combined computer-aided and human eyesight morphological comparisons to reveal the visual similarity between five subspecies of P. bootes and 13 species of Byasa. Our findings demonstrate that the subspecies mindoni and parcesquamata of P. bootes in the western part of its range primarily mimic Byasa species with four hindwing white spots (B. latreillei, B. polla and B. genestieri), while the black subspecies nigricauda and dealbatus in the northeastern part of the range specifically mimic Byasa species without hindwing white spots (B. impediens, B. plutonius and black B. polyeuctes). Between these two extremes, the subspecies rubicundus and the spotted nigricauda mimic several different Byasa species, with the variable B. polyeuctes acting as the morphological bridge between them. Considering the phylogenetic history of Byasa and P. bootes, the authors propose that the four-spotted trait in P. bootes could be ancestral, while the spotless trait may have resulted from subsequent selection. The widespread and morphologically variable B. polyeuctes may enhance its own fitness by potential Müllerian mimicry and also serve as a bridge to mingle P. bootes and various Byasa species through Batesian mimicry in the transition area between four-spotted and spotless Byasa species.