Morphological and statistical perspectives on genital sexual dimorphism in Eupterotidae Swinhoe, 1892 (Insecta: Lepidoptera)

The family Eupterotidae (Lepidoptera) exhibits pronounced sexual dimorphism, particularly in genital structures, which are critical for species identification and understanding evolutionary relationships. This study investigates sexual dimorphism in the genital morphology of select species within the genera Eupterote, Apona, and Ganisa of the subfamily Eupterotinae. Detailed morphological analyses of male and female genitalia were conducted using specimens collected from Himachal Pradesh and Jammu & Kashmir, India. Key findings reveal distinct differences in the uncus, valva, and aedeagus in males, and the corpus bursae, ductus bursae, and apophyses in females across the studied species. Notably, Eupterote species lack a gnathos, while Apona and Ganisa species possess it, with Ganisa showing a unique demarcation between the uncus and tegumen. Principal component analysis of morphometric data highlights significant variation in genital and wing measurements, supporting taxonomic differentiation. These differences underscore the taxonomic significance of genital structures and their role in reproductive isolation. The results enhance the understanding of sexual dimorphism in Eupterotidae and provide insights into their phylogenetic relationships and ecological adaptations.