Geographic distribution of the egg parasitoid Telenomus remus (Hymenoptera: Scelionidae) in Florida and cytochrome c oxidase subunit I based insights into the species population genetic structure.

Telenomus remus Nixon is an important egg parasitoid of the fall armyworm (Spodoptera frugiperda (J.E. Smith)), a major agricultural pest. Originally described in Malaysia in the 1920s, T. remus has since spread across the globe. Although it was released in Florida in the 1970s and 1980s, subsequent surveys suggested it had failed to establish in the state. However, its unexpected detection parasitizing fall armyworm egg masses in Florida in 2009 and 2013 suggested a reassessment of this species within the state was warranted. In this study, we set out fall armyworm sentinel egg masses across 10 counties in Florida to evaluate the current distribution of this parasitoid across the state. We compared cytochrome c oxidase subunit I gene barcodes from our survey to publicly available sequences representing T. remus populations from 24 countries spanning 4 continents and conducted phylogenetic analyses to examine the relationship of T. remus haplotypes with other Telenomus species. Our findings indicate that T. remus is now widely distributed across Florida, though it remains absent in the southeastern region of the state. We also identified 2 T. remus mitochondrial haplogroups, one that is globally distributed in Asia, South America, Africa, and Florida, and a second that was confined to the Eastern Mediterranean region (Israel, Egypt, and Lebanon) and East Africa (Kenya and Tanzania). Our phylogenetic analysis suggests these are 2 mitochondrial variants or strains of the same species, though additional studies are needed to further characterize the genetic variation between these 2 strains, as well as any important biological or ecological differences.