Enhancement of the geomagnetic field reduces the phototaxis of rice brown planthopper
            Nilaparvata lugens
            associated with frataxin down‐regulation

Geomagnetic field (GMF) intensity can be used by some animals to determine their position during migration. However, its role, if any, in mediating other migration-related phenotypes remains largely unknown. Here, we simulated variation in GMF intensity between two locations along the migration route of a nocturnal insect migrant, the brown planthopper Nilaparvata lugens , that varied by approximately 5 µT in field intensity. After one generation of exposure, we tested for changes in key morphological, behavioural and physiological traits related to migratory performance, including wing dimorphism, flight capacity and positive phototaxis. Our results showed that all three morphological and behavioural phenotypes responded to a small difference in magnetic field intensity. Consistent magnetic responses in the expression of the phototaxis-related Drosophila-like cryptochrome 1 ( Cry1 ) gene and levels of two primary energy substrates used during flight, triglyceride and trehalose, were also found. Our findings indicate changes in GMF intensity can alter the expression of phenotypes critical for insect migration and highlight the unique role of magnetoreception as a trait that may help migratory insects express potentially beneficial phenotypes in geographically variable environments.

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Geomagnetic field absence reduces adult body weight of a migratory insect by disrupting feeding behavior and appetite regulation

10.1101/737361 ◽

2019 ◽

Author(s):

Guijun Wan ◽

Shoulin Jiang ◽

Ming Zhang ◽

Jingyu Zhao ◽

Yingchao Zhang ◽

...

Keyword(s):

Body Weight ◽

Feeding Behavior ◽

Geomagnetic Field ◽

Expression Patterns ◽

Brown Planthopper ◽

Nilaparvata Lugens ◽

Zero Magnetic Field ◽

Food Aversion ◽

Glucose Levels ◽

Reduced Body

AbstractThe geomagnetic field (GMF) is well documented for its essential role as a cue used in animal orientation or navigation. Recent evidence indicates that the absence of GMF can trigger stress-like responses such as reduced body weight, as we have previously shown in newly emerged adults of the brown planthopper, Nilaparvata lugens. To test the hypothesis that reduced feeding in the absence of the GMF leads to a decrease of N. lugens body weight, we compared magnetic responses in feeding behavior, glucose levels, and expression of magnetoreception- and appetite-related genes in brown planthopper nymphs exposed to either a near-zero magnetic field (NZMF, i.e., GMF absence) or typical GMF conditions. In addition to observing the expected responses in the expression of the potential magnetosensor cryptochromes, the food intake of 5th instar nymphs was significantly reduced in insects reared in the absence of GMF. Insects that exhibited reduced feeding reared in the absence of the GMF also had higher glucose levels which is associated with food aversion. Expression patterns of appetite-related neuropeptide genes were also altered in the absence of GMF in a manner consistent with diminishing appetite. These findings support the hypothesis that strong changes in GMF intensity can affect insect feeding behavior and underlying regulatory processes. Our results provide further evidence that magnetoreception and regulatory responses to GMF changes can affect a wide variety of biological processes.

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Geomagnetic field intensity as a cue for the regulation of insect migration

10.1101/733782 ◽

2019 ◽

Author(s):

Guijun Wan ◽

Ruiying Liu ◽

Chunxu Li ◽

Jinglan He ◽

Weidong Pan ◽

...

Keyword(s):

Field Intensity ◽

Geomagnetic Field ◽

Brown Planthopper ◽

Nilaparvata Lugens ◽

Primary Energy ◽

Migration Route ◽

Variable Environments ◽

Insect Migration ◽

Cryptochrome 1

AbstractGeomagnetic field (GMF) intensity can be used by some animals to determine their direction and position during migration. However, its role, if any, in mediating other migration-related phenotypes remains largely unknown. Here, we simulated variation in GMF intensity between two locations along the migration route of a nocturnal insect migrant, the brown planthopper Nilaparvata lugens, that varied by ∼5 μT (GMF50μT vs. GMF45μT) in field intensity. After one generation of exposure, we tested for changes in key morphological, behavioural and physiological traits related to migratory performance including wing dimorphism, flight capacity and positive phototaxis. Our results showed that all three morphological and behavioural phenotypes responded to a small difference in magnetic field intensity between the simulated northern vs. southern locations in ways expected along the migratory route. Consistent magnetic responses in the expression of the phototaxis-related Drosophila-like cryptochrome 1 (Cry1) gene and levels of two primary energy substrates used during flight, triglyceride and trehalose, were also found. Our findings indicate GMF intensity can be a cue that regulates the expression of phenotypes critical for insect migration and highlight the unique role of magnetoreception as a trait that can help migratory insects express potentially beneficial phenotypes in geographically variable environments.

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Removal or component reversal of local geomagnetic field affects foraging orientation preference in migratory insect brown planthopper Nilaparvata lugens

PeerJ ◽

10.7717/peerj.12351 ◽

2021 ◽

Vol 9 ◽

pp. e12351

Author(s):

Yingchao Zhang ◽

Weidong Pan

Keyword(s):

Geomagnetic Field ◽

Brown Planthopper ◽

Northeast Asia ◽

Nilaparvata Lugens ◽

Zero Magnetic Field ◽

Orientation Preference ◽

Iron Sulfur Cluster ◽

Directional Information ◽

The Relationship

Background Migratory brown planthopper Nilaparvata lugens (N. lugens) annually migrates to Northeast Asia in spring and returns to Southeast Asia in autumn. However, mechanisms for orientation and navigation during their flight remain largely unknown. The geomagnetic field (GMF) is an important source of directional information for animals (including N. lugens), yet the magnetic compass involved has not been fully identified. Methods Here we assessed the influences of GMF on the foraging orientation preference of N. lugens by removing or component reversal of local GMF. At the same time, we examined the role of iron-sulfur cluster assembly1 (IscA1), a putative component of magnetoreceptor, in the foraging orientation preference of N. lugens under the controlled magnetic fields by RNA silencing (RNAi). Results We found that the near-zero magnetic field (NZMF) or vertical reversal of GMF could lead to N. lugens losing the foraging orientation preference, suggesting that a normal level of GMF, in the way of either intensity or inclination, was essential for the foraging orientation of N. lugens. Moreover, the gene knockdown of IscA1, also affected the foraging orientation preference of N. lugens, pointing out a potential role of IscA1 in the insects’ sensing of variation in the GMF. Discussion These results suggested a foraging orientation preference is associated with the GMF and revealed new insights into the relationship between the IscA1 and magnetosensitivity mechanism in N. lugens.

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