Medical/biological study (experimental study)

Reproducibility and Desensitization of the Power Frequency Magnetic Field Effect on Movement of the Common Cutworm Spodoptera Litura med./bio.

By: Ryu JM, Kim NJ, Won R, Lee SD, Chae KS

Published in: Entomol Res 2009; 39 (6): 406-409

Aim of study (acc. to author)

To investigate the effect of exposure to an extremely low frequency magnetic field on the movement of the common cutworm Spodoptera litura.

Background/further details

After an acclimatization period of 24 hours in the petri dishes, the larvae (caterpillar) were submitted to one of four experimental schemes:
1.) 1 h without any treatment ("cage control"),
2.) 1 h sham exposure (n=18) + 1 h sham exposure (n=18),
3.) 1 h sham exposure (n=45) + 1 h magnetic field exposure (n=45) and
4.) 1 h sham exposure (n=18) + 1 h magnetic field exposure (n=18) followed by 1 h sham exposure (n=18) + 1 h magnetic field exposure (n=18) followed again by 1 h sham exposure (n=9) + 1 h magnetic field exposure (n=9) .
The fourth experiment was performed to test whether the observed effects are reproducible with the same larvae. All experiments were repeated two or three times.

Endpoint

cognitive/behavioral endpoints: motor activity

Exposure

- 50/60 Hz
- magnetic field

Exposure	Parameters
Exposure 1: 60 Hz Exposure duration: up to 3 hours (à 1 hour exposures, see background/further details)	magnetic flux density: 1 mT

Exposure 1

Main characteristics

Frequency	60 Hz
Type	magnetic field
Exposure duration	up to 3 hours (à 1 hour exposures, see background/further details)

Exposure setup

Exposure source	Helmholtz coils
Chamber	larvae were exposed in Petri dishes (35 mm diameter)
Setup	rectangular Helmholtz coils, temperature inside the exposure system 25 ± 0.5°C
Sham exposure	A sham exposure was conducted.
Additional info	intensity of the ambient stray magnetic field was less than 0.05 µT

Parameters

Measurand	Value	Type	Method	Mass	Remarks
magnetic flux density	1 mT	-	measured	-	-

Reference articles

Koh EK et al. (2008): A 60-Hz sinusoidal magnetic field induces apoptosis of prostate cancer cells through reactive oxygen species
Chae KS (2008): An extremely low frequency magnetic field increases unconditioned larval movement of the common cutworm, Spodoptera litura: A novel model for a magnetoreceptive neurobehavioral study

Exposed system:

invertebrate
common cutworm larvae (Spodoptera litura)

Methods Endpoint/measurement parameters/methodology

cognitive/behavioral endpoints: motor activity (any movement lasting more than 5 seconds was counted except for eating or excretion movement; recording by a camcorder)

Investigated system:

investigation on living organism

Time of investigation:

during exposure

Main outcome of study (acc. to author)

The magnetic field exposed larvae of the third experiment showed a reduced motor activity in comparison to the sham exposed larvae of the second experiment (not significant). In the fourth experiment, larvae exposed for the first and for the second time showed a significantly decreased motor activity compared to the former sham exposure, respectively. However, larvae exposed for the third time showed no mentionable difference in the motor activity when compared to the former sham exposure.
The authors conclude that exposure to extremely low frequency magnetic fields could affect the motor activity of insect larvae.

Study character:

medical/biological study
experimental study
full/main study
blind study

Study funded by

Kyungpook National University Research Fund, Korea

Zmejkoski D et al. (2017): Different responses of Drosophila subobscura isofemale lines to extremely low frequency magnetic field (50 Hz, 0.5 mT): fitness components and locomotor activity
Valadez-Lira JA et al. (2017): Alterations of Immune Parameters on Trichoplusia ni (Lepidoptera: Noctuidae) Larvae Exposed to Extremely Low-Frequency Electromagnetic Fields
Wyszkowska J et al. (2016): Exposure to extremely low frequency electromagnetic fields alters the behaviour, physiology and stress protein levels of desert locusts
Dimitrijevic D et al. (2014): Extremely low frequency magnetic field (50 Hz, 0.5 mT) modifies fitness components and locomotor activity of Drosophila subobscura
Dimitrijević D et al. (2013): Temporal pattern of Drosophila subobscura locomotor activity after exposure to extremely low frequency magnetic field (50 Hz, 0.5 mT)
El Kholy SE et al. (2012): Effect of 60 minutes exposure to electromagnetic field on fecundity, learning and memory, speed of movement and whole body protein of the fruit fly Drosophila melanogaster
Chae KS (2008): An extremely low frequency magnetic field increases unconditioned larval movement of the common cutworm, Spodoptera litura: A novel model for a magnetoreceptive neurobehavioral study
Prolic Z et al. (2003): Behavioral differences of the insect Morimus funereus (Coleoptera, Cerambycidae) exposed to an extremely low frequency magnetic field