title: Behavioral evidence for a magnetic sense in the oriental armyworm,Mythimna separata.
abstract: Progress has been made in understanding the mechanisms underlying directional navigation in migratory insects, yet the magnetic compass involved has not been fully elucidated. Here we developed a flight simulation system to study the flight directionality of the migratory armywormMythimna separatain response to magnetic fields. Armyworm moths were exposed to either a 500 nT extreme weak magnetic field, 1.8 T strong magnetic field, or a deflecting magnetic field and subjected to tethered flight trials indoors in the dark. The moths were disoriented in the extreme weak magnetic field, with flight vectors that were more dispersed (variance=0.60) than in the geomagnetic field (variance=0.32). After exposure to a 1.8 T strong magnetic field, the mean flight vectors were shifted by about 105° in comparison with those in the geomagnetic field. In the deflecting magnetic field, the flight directions varied with the direction of the magnetic field, and also pointed to the same direction of the magnetic field. In the south-north magnetic field and the east-west field, the flight angles were determined to be 98.9° and 166.3°, respectively, and formed the included angles of 12.66° or 6.19° to the corresponding magnetic direction. The armyworm moths responded to the change of the intensity and direction of magnetic fields. Such results provide initial indications of the moth reliance on a magnetic compass. The findings support the hypothesis of a magnetic sense used for flight orientation in the armywormMythimna separata.
authors.affiliation: Beijing Key Laboratory of Bioelectromagnetics, Institute of Electrical Engineering, Chinese Academy of Sciences, Beijing 100190, China.|Department of Electrical Engineering, University of Chinese Academy of Sciences, Beijing 100049, China.
authors.forename: Jingjing
authors.initials: J
authors.lastname: Xu
authors.affiliation: Beijing Key Laboratory of Bioelectromagnetics, Institute of Electrical Engineering, Chinese Academy of Sciences, Beijing 100190, China.|Department of Electrical Engineering, University of Chinese Academy of Sciences, Beijing 100049, China.
authors.forename: Wei
authors.identifier: http://orcid.org/0000-0003-4523-6546
authors.initials: W
authors.lastname: Pan
authors.affiliation: Beijing Key Laboratory of Bioelectromagnetics, Institute of Electrical Engineering, Chinese Academy of Sciences, Beijing 100190, China.|Department of Electrical Engineering, University of Chinese Academy of Sciences, Beijing 100049, China.
authors.forename: Yingchao
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: Beijing Key Laboratory of Bioelectromagnetics, Institute of Electrical Engineering, Chinese Academy of Sciences, Beijing 100190, China.
authors.forename: Yue
authors.initials: Y
authors.lastname: Li
authors.affiliation: Department of Entomology, College of Plant Protection, Nanjing Agricultural University, Nanjing 210095, China.
authors.forename: Guijun
authors.initials: G
authors.lastname: Wan
authors.affiliation: Department of Entomology, College of Plant Protection, Nanjing Agricultural University, Nanjing 210095, China.
authors.forename: Fajun
authors.initials: F
authors.lastname: Chen
authors.affiliation: Department of Entomology, Texas A&M University, College Station, TX 77843, USA.
authors.forename: Gregory A
authors.initials: GA
authors.lastname: Sword
authors.affiliation: Beijing Key Laboratory of Bioelectromagnetics, Institute of Electrical Engineering, Chinese Academy of Sciences, Beijing 100190, China panwd@mail.iee.ac.cn.
authors.forename: Weidong
authors.initials: W
authors.lastname: Pan
keywords: Flight simulation; Magnetic compass; Magnetic sense; Mythimna separata; Orientation