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.
|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|
|magnetic flux density||1 mT||-||measured||-||-|
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.