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

Authors: TESSNOW, A - University Of Florida; Meagher Jr, Robert; QURESHI, J - University Of Florida; BEUZELIN, J - University Of Florida; SEAL, D - University Of Florida

Submitted to: Environmental Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/4/2026
Publication Date: 5/27/2026
Citation: Tessnow, A.E., Meagher Jr, R.L., Qureshi, J.A., Beuzelin, J.M., Seal, D. 2026. 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. Environmental Entomology. https://doi.org/10.1093/ee/nvag058.
DOI: https://doi.org/10.1093/ee/nvag058

Interpretive Summary: Insect pests have many natural enemies, such as predators and parasites, that can naturally reduce population levels. The small wasp Telenomus remus is an important egg parasite of the fall armyworm, a major agricultural pest across the globe. Although wasps were released for biological control in southeastern Florida in the 1970s and 1980s, subsequent surveys suggested they had failed to establish populations. However, its unexpected detection parasitizing fall armyworm egg masses in north-central Florida in 2009 and 2013 suggested a reassessment of this species within the state was warranted. Scientists from USDA-ARS, Center for Medical, Agricultural and Veterinary Entomology in Gainesville, Florida, along with entomologists from three University of Florida Research and Education Centers, placed fall armyworm sentinel egg masses across 10 counties to attract T. remus and evaluate the current distribution. Our findings indicate that T. remus is now widely distributed across Florida, though it remains absent in the southeastern region of the state where the original releases were made almost 50 years ago. We also genetically compared specimens recovered from our survey to publicly available DNA sequences representing T. remus populations from 24 countries. Specimens found in Florida are genetically similar to a group that is distributed in Asia, South America, and Africa, compared to a second group that is confined to the Eastern Mediterranean region (Israel, Egypt, and Lebanon) and East Africa (Kenya and Tanzania). It still isn't known how the wasps arrived in north-central Florida and why they are not found in southeastern Florida, although fall armyworm is a serious pest of sweet corn in the region.

Technical Abstract: 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 as a biological control agent, 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 COI barcodes from our survey to publicly available sequences representing T. remus populations from 24 countries spanning four 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 two 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 two mitochondrial variants or strains of the same species, though additional studies are needed to further characterize the genetic variation between these two strains, as well as any important biological or ecological differences.