title: Spodoptera frugiperda (Lepidoptera: Noctuidae) host-plant variants: two host strains or two distinct species?
abstract: The moth Spodoptera frugiperda is a well-known pest of crops throughout the Americas, which consists of two strains adapted to different host-plants: the first feeds preferentially on corn, cotton and sorghum whereas the second is more associated with rice and several pasture grasses. Though morphologically indistinguishable, they exhibit differences in their mating behavior, pheromone compositions, and show development variability according to the host-plant. Though the latter suggest that both strains are different species, this issue is still highly controversial because hybrids naturally occur in the wild, not to mention the discrepancies among published results concerning mating success between the two strains. In order to clarify the status of the two host-plant strains of S. frugiperda, we analyze features that possibly reflect the level of post-zygotic isolation: (1) first generation (F1) hybrid lethality and sterility; (2) patterns of meiotic segregation of hybrids in reciprocal second generation (F2), as compared to the meiosis of the two parental strains. We found a significant reduction of mating success in F1 in one direction of the cross and a high level of microsatellite markers showing transmission ratio distortion in the F2 progeny. Our results support the existence of post-zygotic reproductive isolation between the two laboratory strains and are in accordance with the marked level of genetic differentiation that was recovered between individuals of the two strains collected from the field. Altogether these results provide additional evidence in favor of a sibling species status for the two strains.
authors.affiliation: UM - UMR 1333 DGIMI, Université Montpellier, Place Eugène Bataillon, 34095, Montpellier, France, pascalinedumas@gmail.com.
authors.forename: Pascaline
authors.initials: P
authors.lastname: Dumas
authors.forename: Fabrice
authors.initials: F
authors.lastname: Legeai
authors.forename: Claire
authors.initials: C
authors.lastname: Lemaitre
authors.forename: Erwan
authors.initials: E
authors.lastname: Scaon
authors.forename: Marion
authors.initials: M
authors.lastname: Orsucci
authors.forename: Karine
authors.initials: K
authors.lastname: Labadie
authors.forename: Sylvie
authors.initials: S
authors.lastname: Gimenez
authors.forename: Anne-Laure
authors.initials: AL
authors.lastname: Clamens
authors.forename: Hélène
authors.initials: H
authors.lastname: Henri
authors.forename: Fabrice
authors.initials: F
authors.lastname: Vavre
authors.forename: Jean-Marc
authors.initials: JM
authors.lastname: Aury
authors.forename: Philippe
authors.initials: P
authors.lastname: Fournier
authors.forename: Gael J
authors.initials: GJ
authors.lastname: Kergoat
authors.forename: Emmanuelle
authors.initials: E
authors.lastname: d'Alençon
mesh_terms: D000818:Animals; D003433:Crosses, Genetic; D005260:Female; D005298:Fertility / Q000235:genetics; D005819:Genetic Markers; D060005:Genotyping Techniques; D058507:Host Specificity; D006824:Hybridization, Genetic; D008297:Male; D018895:Microsatellite Repeats; D012275:Oryza; D018411:Spodoptera / Q000145:classification* / Q000235:genetics; D003313:Zea mays
chemical_list: D005819:Genetic Markers