title: Genetic basis of allochronic differentiation in the fall armyworm.
abstract: Very little is known on how changes in circadian rhythms evolve. The noctuid moth Spodoptera frugiperda (Lepidoptera: Noctuidae) consists of two strains that exhibit allochronic differentiation in their mating time, which acts as a premating isolation barrier between the strains. We investigated the genetic basis of the strain-specific timing differences to identify the molecular mechanisms of differentiation in circadian rhythms.
  
  
  
  Through QTL analyses we identified one major Quantitative trait chromosome (QTC) underlying differentiation in circadian timing of mating activity. Using RADtags, we identified this QTC to be homologous to Bombyx mori C27, on which the clock gene vrille is located, which thus became the major candidate gene. In S. frugiperda, vrille showed strain-specific polymorphisms. Also, vrille expression differed significantly between the strains, with the rice-strain showing higher expression levels than the corn-strain. In addition, RT-qPCR experiments with the other main clock genes showed that pdp1, antagonist of vrille in the modulatory feedback loop of the circadian clock, showed higher expression levels in the rice-strain than in the corn-strain.
  
  
  
  Together, our results indicate that the allochronic differentiation in the two strains of S. frugiperda is associated with differential transcription of vrille or a cis-acting gene close to vrille, which contributes to the evolution of prezygotic isolation in S. frugiperda.
authors.affiliation: Max Planck Institute for Chemical Ecology, Entomology, Hans-Knöll-Str. 8, 07745, Jena, Germany. shaenniger@ice.mpg.de.
authors.forename: Sabine
authors.identifier: 0000-0001-8758-3568
authors.initials: S
authors.lastname: Hänniger
authors.affiliation: Institute for Biodiversity and Ecosystem Dynamics, University of Amsterdam, Science Park 904, 1098 XH, Amsterdam, The Netherlands.
authors.forename: Pascaline
authors.initials: P
authors.lastname: Dumas
authors.affiliation: DKMS Life Science Lab, Fiedlerstr, 34, 01307, Dresden, Germany.
authors.forename: Gerhard
authors.initials: G
authors.lastname: Schöfl
authors.affiliation: Max Planck Institute for Chemical Ecology, Entomology, Hans-Knöll-Str. 8, 07745, Jena, Germany.
authors.forename: Steffi
authors.initials: S
authors.lastname: Gebauer-Jung
authors.affiliation: Max Planck Institute for Chemical Ecology, Entomology, Hans-Knöll-Str. 8, 07745, Jena, Germany.
authors.forename: Heiko
authors.initials: H
authors.lastname: Vogel
authors.affiliation: Max Planck Institute for Chemical Ecology, Entomology, Hans-Knöll-Str. 8, 07745, Jena, Germany.
authors.forename: Melanie
authors.initials: M
authors.lastname: Unbehend
authors.affiliation: Max Planck Institute for Chemical Ecology, Entomology, Hans-Knöll-Str. 8, 07745, Jena, Germany.
authors.forename: David G
authors.initials: DG
authors.lastname: Heckel
authors.affiliation: Max Planck Institute for Chemical Ecology, Entomology, Hans-Knöll-Str. 8, 07745, Jena, Germany.|DKMS Life Science Lab, Fiedlerstr, 34, 01307, Dresden, Germany.
authors.forename: Astrid T
authors.initials: AT
authors.lastname: Groot
mesh_terms: D000818:Animals; D002940:Circadian Rhythm; D017344:Genes, Insect; D007814:Larva / Q000235:genetics; D012275:Oryza; D011110:Polymorphism, Genetic; D012098:Reproduction; D012621:Seasons; D018411:Spodoptera / Q000145:classification / Q000235:genetics* / Q000254:growth & development / Q000502:physiology; D003313:Zea mays