DNA barcoding and morphology resolve the identity of the Seasonal Hyperacute Panuveitis-associated Gazalina chrysolopha (Lepidoptera; Notodontidae) in Nepal

Moths of the genus Gazalina are implicated in the etiology of Seasonal Hyperacute Panuveitis (SHAPU), an enigmatic eye disease prevalent in Nepal. However, the precise causative species has remained unconfirmed due to a historical reliance on purely morphological identification. To definitively identify the responsible species, we collected Gazalina specimens from Dhorpatan Municipality, one of the epicentres of the SHAPU outbreak in Baglung District, western Nepal. We employed an integrative taxonomic approach, combining morphological evaluation with molecular phylogenetic analysis of a fragment of the cytochrome c oxidase subunit I (COI, 657 bp) gene. Morphological assessment suggested the specimens as Gazalina chrysolopha, based on the presence of a distinctive golden abdominal tuft of setae in females and three medial forewing lines. Maximum likelihood phylogenetic analysis on COI gene sequences corroborated this, revealing that the outbreak specimens form a monophyletic clade with G. chrysolopha from India and Pakistan. Additionally, genetic distance analysis demonstrated a minimal divergence (3.69%) between the Nepalese specimens and the Indian G. chrysolopha population. This study provides the first robust molecular evidence confirming G. chrysolopha as the biological agent associated with SHAPU outbreaks in Nepal. Future research should prioritise fine-scale distributional mapping of G. chrysolopha and investigate the evolutionary history of the genus across the Hindu-Kush Himalayas.