Morphology, diversity and phylogenetic analysis of Spodoptera exigua (Lepidoptera: Noctuidae) in North Sulawesi by employing partial mitochondrial cytochrome oxidase 1 gene sequences

Spodoptera exigua (Hübner, 1808) (Lepidoptera: Noctuidae) is a significant agricultural crop pest in Indonesia, causing significant economic losses in recent years. This species' ability to survive on a wide variety of host plants provides an adaptive advantage for survival in the environment, which is facilitated by its high mobility, fecundity, and capability to acquire resistance to a broad spectrum of chemical pesticides. It is well-established that knowledge of diversity and evolutionary origins facilitate the development of pest management strategies. In the present study, we report the morphology, diversity and phylogeny analysis of S. exigua from North Sulawesi, Indonesia. The specimen from Rurukan have a body size and other segments that are longer than in Langowan and Modoinding. Dendrogram analysis shows that the similarity distance based on morphology ranges from 1-25%, which forms four clusters, where the specimen from Rurukan is separated from the rest of the specimens. The phylogeny of S. exigua from North Sulawesi, Indonesia, based on CO1 (Cytochrome c oxidase subunit 1) gene fragment, which is juxtaposed with CO1 data of the allied species from many geographical locations. A total of twenty-five isolates representing Indonesia, Japan, Germany, Thailand, India, UK, USA, Spain and Australia were compared. Nineteen sequences of S. exigua retrieved from GenBank were selected as references based on previous published phylogenic trees. The twenty-four isolates were scattered in two distinct clades indicating S. exigua is polyphyletic, but S. exigua from North Sulawesi, Indonesia is monophyletic.