Population structure of Spodoptera frugiperda (Lepidoptera: Noctuidae) corn- and rice-host forms in South America: Are they host strains?

JUÁREZ, M. L.; SCHÖFL, G.; VERA, M.T.; VILARDI, J. C.; MURÚA, G.; WILLINK, E.; HÄNNIGER, S.; HECKEL, D.G.; GROOT, A.T.

ENTOMOLOGIA EXPERIMENTALIS ET APPLICATA

WILEY-BLACKWELL PUBLISHING, INC

Lugar: Londres; Año: 2014

0013-8703

10-Jun-2014 Dear Dr. Juárez, Your manuscript EEA-2014-0028.R1 entitled "Population structure of Spodoptera frugiperda (Lepidoptera: Noctuidae) corn- and rice-host forms in South America: Are they host strains?" has been accepted for publication in Entomologia Experimentalis et Applicata. Before we send your paper to Production, we will check your files and send you an email about final corrections. As part of the Journal?s continued commitment to its authors, the Editorial Office and Publisher wish to keep you informed about the subsequent steps in the production of your paper. The attached document ?Publisher?s information for authors? contains important information regarding journal publication and services for authors; you may wish to save it for future reference. Yours sincerely, Steph B.J. Menken Editor-in-Chief Entomologia Experimentalis et Applicata s.b.j.menken@uva.nl Determining which factors contribute to the formation and maintenance of genetic divergence to evaluate its relative importance as a cause of biological differentiation are among the major challenges in evolutionary biology. In Spodoptera frugiperda (Smith) (Lepidoptera: Noctuidae) two host strains have been recognized in the 1980s: the corn-strain prefers corn, sorghum and cotton, while the rice-strain prefers rice and wild grasses. However, it is not clear to what extent these so-called ?strains?, which have also been called ?host races? or even ?sibling species?, are really associated with host plants. Due to the indeterminate evolutionary status, we will use the term ?host forms?. Here, we characterized populations collected from corn, rice and grasses from three countries in South America. Using two mtCOI markers and ten polymorphisms in the Triose phosphate isomerase (Tpi) gene, we found different patterns of host-association. 227 nuclear AFLP markers revealed significant genetic differentiation between populations, which was generally correlated to the host from which the larvae were collected. Using a multivariate discriminant analysis and a Bayesian clustering approach, we found that individuals could be grouped into 2-5 genetically distinct clusters, depending on the method. Together, our results indicate that although host-associated differentiation is present in this species, it does not account for all observable genetic variation and other factors must be maintaining genetic differentiation between these forms. Therefore, the term ?host strains? should be abandoned and ?host forms? should be used instead for Spodoptera frugiperda.