Flight phenology of Spodoptera frugiperda (Lepidoptera: Noctuidae) and insights into the moth origin based on hydrogen isotopes

The flight phenology and origins of economically important pests are crucial to design IPM/IRM programs. Migration patterns of Spodoptera frugiperda have been based on COI mitochondrial haplotypes, which have limitations in populations of rice strain and hybrids with corn strain. Using stable hydrogen isotopes in wing tissue, we studied the migratory dynamics and native origins of S. frugiperda in the Florida Panhandle. This region serves as a significant influx region of S. frugiperda populations from the overwintering sites of south Texas and south Florida. However, the impact of tropical storm events potentially influencing population dynamics has never been investigated. In this study, moths were collected year-round in delta traps with sex pheromone lure, from 2018 to 2023, at West Florida Research and Education Center, Jay, FL. Traps were evaluated biweekly, and wings were processed for stable hydrogen isotope analysis. Our results indicate that moths exhibit year-round flight activity, with peak activity observed from August to November following increased activity in July, and subsequently declining in December. Using stable hydrogen isotope analysis, we categorized moths into different regional origins, revealing spatial and temporal variations in their flight patterns and origin. The impact of tropical storms in flight phenology and moth origin will be presented considering the relevance to IPM and IRM programs.