Fall armyworm migration across the Lesser Antilles and the potential for genetic exchanges between North and South American populations

Authors: Nagoshi, Rodney; FLEISCHER, SHELBY - Pennsylvania State University; Meagher, Robert - Rob; HAY-ROE, MIRIAN - University Of Florida; KHAN, AYUB - University Of The West Indies; MURUA, M. - Consejo Nacional De Investigaciones Científicas Y Técnicas(CONICET); SILVIE, PIERRE - Cirad, France; Westbrook, John

Submitted to: PLOS ONE
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/31/2017
Publication Date: 2/6/2017
Citation: Nagoshi, R.N., Fleischer, S., Meagher Jr, R.L., Hay-Roe, M., Khan, A., Murua, M.G., Silvie, P., Westbrook, J.K. 2017. Fall armyworm migration across the Lesser Antilles and the potential for genetic exchanges between North and South American populations. PLoS One. 12(2):e0171743.
DOI: https://doi.org/10.1371/journal.pone.0171743

Interpretive Summary: The introduction of invasive pest species and/or deleterious traits (i.e., pesticide resistance) into domestic pest populations poses a continuing threat to agriculture. Fall armyworm is a major pest of corn and other crops in both North and South America and exhibits long distance migration behavior in North America. Pesticide resistance traits have been identified in both continents and there is concern about how quickly these traits can disperse to the other continent by natural migration. In this study an international collaboration of scientists led by researchers at the USDA, Agricultural Research Service, Center for Medical Agricultural and Veterinary Entomology, Gainesville, Florida, investigated fall armyworm movements across the Lesser Antilles islands in the southern Caribbean. Genetic haplotyping previously developed by the USDA scientists was used to examine fall armyworm populations in the Caribbean islands and was coupled with wind analysis to establish movement patterns. The data indicate population movements of the fall armyworm across the Lesser Antilles are sporadic and limited. This observation suggests that such migration is minor and infrequent, providing few opportunities for genetic exchanges and that the spread of resistance from the Caribbean islands would most likely not be based on wind driven migration.

Technical Abstract: The fall armyworm, Spodoptera frugiperda (J. E. Smith)(Lepidoptera: Noctuidae), is an important agricultural pest of the Western Hemisphere noted for its broad host range, long distance flight capabilities, and a propensity to develop resistance to pesticides that includes a subset of those used in genetically modified corn varieties. These characteristics exacerbate the threat fall armyworm poses to agriculture, with the potential that a resistance trait arising in one geographical location could rapidly disseminate throughout the hemisphere. A region of particular concern is the Caribbean, where a line of islands that extends from Florida to Venezuela provides a potential migratory pathway between populations from North and South America that could allow for consistent and substantial genetic interactions. In this study, surveys of populations from Peru, Bolivia, Paraguay, and Trinidad expand on previous work in South America that indicates a generally homogeneous population with respect to haplotype markers. This population differs from that found in most of the Lesser Antilles where a combination of genetic and meteorological observations is described that indicate fall armyworm migration from Puerto Rico to as far south as Barbados, but does not support significant incursion into Trinidad and South America. Air transport projections demonstrate that the wind patterns in the Caribbean region are not conducive to consistent flight along the north-south orientation of the Lesser Antilles, supporting the conclusion that such migration is minor and sporadic, providing few opportunities for genetic exchanges. The implications of these findings on the dissemination of deleterious traits between the two Western Hemisphere continents are discussed.