Multilocus Genetic Analysis of Host Use, Introgression, and Speciation in Host Strains of Fall Armyworm (Lepidoptera: Noctuidae)
By D. Prowell, M. McMichael, Jean-François Silvain. 2004
252 citations recorded by the source corpus.
Abstract Two genetically differentiated forms of fall armyworm, Spodoptera frugiperda (J. E. Smith), use different graminaceous host plants, coexist sympatrically throughout their ranges, yet seem to hybridize. To address the taxonomic status of the two forms, determine extent and directionality of hybridization, and examine host specificity, we compiled multilocus genotypes consisting of mitochondrial DNA (mtDNA) haplotypes, an esterase locus, and eight amplified fragment-length polymorphism (AFLP) loci in moths collected across a broad geographic range. Multilocus analyses indicated 16% of individuals sampled were potentially hybrids with a minority being F1 in origin. Analysis of host use indicated asymmetries in host specificity with one strain specific to corn, Zea mays L., and the other strain predominating on pasture grasses and rice, but occasionally using corn. Location of hybrids in nature was biased toward cornfields, the habitat used by both strains. To assess genetic divergence of each gene, we calculated their relative strain discriminating ability. Eight AFLP loci collectively had the greatest discriminating power (98%), followed by a single AFLP locus (93%) and mtDNA (91%). Esterase exhibited 89% discrimination. Esterase is X-linked along with an assortative mating trait, suggesting esterase differentiation may be maintained by association with strain-specific fitness genes. Despite strong discrimination of these genes, most of the genome surveyed was not distinct. Cytonuclear comparisons provided evidence for unidirectional matings consistent with mate preference studies. Collectively, these data support introgressive hybridization between recently evolved species that are not completely reproductively isolated. Genetic divergence in the presence of gene flow may be a common phase in the speciation process, especially in taxa whose ranges have been altered dramatically by humans.
Subfields: Genetics, Insect Science, Molecular Biology
View Paper: https://www.semanticscholar.org/paper/1950d5bb2aed1bfcb52b7becc5f4073bfd2ca887
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Citations in the corpus
- The roles and interactions of reproductive isolation mechanisms in fall armyworm (Lepidoptera: Noctuidae) host strains (2010, methodology): “Prowell et al. (2004) estimated that 16% of 162 field-collected individuals were potential hybrids with the majority being second or later generation.”
- Field Efficacy of Insecticides for Management of Invasive Fall Armyworm, Spodoptera frugiperda (J. E. Smith) (Lepidoptera: Noctuidae) on Maize in India (2020, background): “The mortality data were corrected by the Abbott’s formula (Abbott 1925) and subjected to Probit analysis using the statistical program SPSS version 16.0 software (IBM SPSS, Armonk, New York, USA) to obtain the LC50, fiducial limits (95%), slopes, and Chi-square values.”
- Identification and Comparison of Fall Armyworm (Lepidoptera: Noctuidae) Host Strains in Brazil, Texas, and Florida (2007, background): “Allozyme and mitochondrial haplotype analyses of larvae from French Guiana identiÞed the two strains, but there was no evidence of plant host speciÞcity as the R-strain predominated in both corn- and turf-dominated habitats ( Prowell et al. 2004 ).”
- The Fall Armyworm Triose Phosphate Isomerase (Tpi) Gene as a Marker of Strain Identity and Interstrain Mating (2010, background): “The different inheritance patterns exhibited by the Tpi and COI genes made possible an examination of interstrain hybridization behavior in the Þeld that conÞrmed and extended the major Þndings of past multi-locus studies (Nagoshi and Meagher 2003a, Prowell et al. 2004, Nagoshi et al. 2006b).”